Pediatric Residency Training Program
Tiffany Merrill Becker M.D.
Frederick D. Watanabe M.D.
Lloyd J. Brown M.D.
- General Concepts
- Essential nutrientscannot be synthesized by the body and must be derived from the diet. These include certain vitamins, minerals, amino acids, fatty acids, and a carbohydrate source.
- Nonessential nutrientscan be synthesized from other compounds or may be derived from the diet.
- Macronutrientssupply energy and essential nutrients needed for growth, development, disease prevention, and activity.
- Carbohydratesmake up approximately 50% of a typical diet and are converted by the body to glucose and other monosaccharides.
- Proteinsare converted to peptides and amino acids. Of the 20 amino acids, nine are essential. As compared with adults, infants require more protein in their diet (2.2 g/kg during infancy decreasing to 0.8 g/kg during adulthood).
- Fatsare broken down into fatty acids and glycerol. Essential fatty acids play an important role in infant brain development. Less than 30% of all calories should come from fats.
- Minerals, including sodium, chloride, potassium, calcium, phosphorus, and magnesium, are also required daily.
- Water-soluble vitaminsinclude vitamin C and the B-complex vitamins (thiamine, riboflavin, niacin, pyridoxine, folic acid, cobalamin, biotin, and pantothenic acid).
- Fat-soluble vitaminsinclude vitamins A, D, E, and K.
- Essential trace minerals, such as iron, iodine, fluorine, zinc, chromium, selenium, and copper, play important roles in metabolism and as enzyme cofactors.
- Certain clinical features are associated with vitamin and mineral deficiencies (Table 10-1).
- Marasmusis the most common energy depletion state and is characterized by near starvation from protein and nonprotein deficiencies. The patient is typically very thin from loss of muscle and body fat.
- Kwashiorkoris less common and is seen in the parts of the world in which starches are the main dietary staple. This protein-deficient state is characterized by generalized edema, abdominal distension, changes in skin pigmentation, and thin, sparse hair.
- Most patients suffering from malnutrition have a combination of energy and protein depletion. The term protein-energy malnutritionis used to describe this state.
Table 10-1. Clinical Features of Selected Vitamin and Mineral Deficiencies
- General Concepts
- Definition.Malabsorption is the inadequate absorption of nutrients and is most often characterized by diarrhea, abdominal distension, and impaired growth.
- Normal physiology
- Digestionis an intraluminal event requiring digestive enzymes and bile acids for micelle formation.
- Absorptionrequires an adequate intestinal mucosal surface and villous brush border with intact transport mechanisms.
- Pathophysiology and etiology
- Undigested sugars are osmotically activeand draw water into the intestinal lumen, causing increased stool volume, increased peristaltic activity, and decreased transit time. This results in diminished digestion and absorption of nutrients.
- Unabsorbed sugars are fermented by colonic bacteria, which produce hydrogen gas, carbon dioxide, and acids.
- The resulting stool is watery and acidicand contains unabsorbed sugars detected as reducing substances by a positive Clinitest reaction. A stool pH below 5.6 suggests carbohydrate malabsorption.
- Causesof carbohydrate malabsorption include isolated congenital enzyme deficiency (e.g., lactase deficiency) or mucosal atrophy, which can cause a loss of enzymes or a disruption of transport mechanisms.
- Dietary proteins are broken down into amino acids or oligopeptides by pepsinogen and pancreatic proteases in the proximal small intestine.
- Causesof protein malabsorption
- Congenital enterokinase deficiencyis a rare cause of massive protein and nitrogen loss in the stool. Hypoproteinemia with resultant edema and growth impairmentdevelops.
- Protein-losing enteropathiesresult in hypoproteinemia as a result of transudation of protein from inflamed intestinal mucosa.
- Inflammatory disordersof the intestinal mucosa, such as Crohn's disease (see section IX) and colitis, may also result in protein loss.
- Fecal α1-antitrypsin levelsmay be used to document enteric protein losses.
- Fats are insoluble in water and must be incorporated into bile salt micelles to be absorbed. Pancreatic lipase is a necessary enzyme that hydrolyzes triglycerides for emulsification.
- Decreased lipase activityresults in steatorrhea (fat in stool) and decreased absorption of fat-soluble vitamins (vitamins A, D, E, and K).
- Causesof fat malabsorption
- Exocrine pancreatic insufficiency(e.g., cystic fibrosis, Schwachman-Diamond syndrome, chronic pancreatitis)
- Intestinal mucosal atrophy, bile acid deficiency, and abetalipoproteinemia
- Stool studiesfor fat, carbohydrates, pH, reducing substances, and α1-antitrypsin should be performed.
- A compete blood count (CBC)may be suggestive.
- A macrocytic blood smear suggests folic acid or vitamin B12deficiency.
- Acanthocytosis of erythrocytes is seen in abetalipoproteinemia.
- Neutropenia may suggest Schwachman-Diamond syndrome, an autosomal recessive disorder characterized by pancreatic exocrine insufficiency, failure to thrive (FTT), short stature, neutropenia, and sometimes pancytopenia.
- Low serum albuminmay be seen in protein-losing enteropathies.
- Infection withGiardia lamblia can cause chronic malabsorption and can be diagnosed by stool studies (see Chapter 7, section XV.B.4).
- Small bowel biopsyis used to diagnose celiac disease (see section II.C), abetalipoproteinemia, and some infectious disorders and enzyme deficiencies.
- Protein Intolerance
- Definition.Protein intolerance is characterized by diarrhea, vomiting, and colicky abdominal pain that occur after exposure to dietary protein.
- Epidemiology.Protein intolerance occurs in up to 8% of children. Cow's milk protein causes the majority of these reactions. Other causes include soy and egg proteins.
- Clinical features
- Enteropathy, which is characterized by progressive onset of diarrhea, vomiting, irritability, and abdominal pain. Chronic blood loss in the stool may lead to anemia, and significant stool protein loss may cause edema and FTT.
- Enterocolitis, which typically presents acutely with diarrhea, rectal bleeding, mucus in the stool, abdominal distension, and irritability. As with enteropathy, hypoproteinemia, edema, and FTT may develop.
- Diagnosisis made by resolution of acute symptoms within a few days after complete withdrawal of the suspected antigen. Chronic symptoms usually resolve within 1–2 weeks.
- Managementincludes withdrawal and avoidance of suspected dietary protein. Most protein intolerance is transitory and resolves by 1–2 years of age.
- Celiac Disease (Gluten-Sensitive Enteropathy)
- Definition.This autoimmune disorder of the proximal small intestine is characterized by intolerance to gluten, which results in mucosal damage.
- Celiac disease is most common in regions where wheat is a staple in the diet (e.g., North America, Europe, Australia). In the United States, the incidence is as high as 1 in 250 individuals.
- Celiac disease generally presents between 6 months and 2 years of agewhen gluten, found in wheat, rye, barley, and oats (if the oats are harvested in fields that also contain wheat), is introduced into the diet. The disease may sometimes present in adulthood.
- Individuals who are susceptible to celiac disease may have a genetic predisposition.
- Clinical features
- The primary symptoms are diarrhea, vomiting, bloating, anorexia, and sometimes FTT.Diarrhea may not be present in all patients.
- Irritability is common in infants.
- Abdominal pain and large, foul-smelling stools are also common.
- Small bowel biopsyis the gold standard for diagnosis and demonstrates short, flat villi, deep crypts, and vacuolated epithelium with lymphocytes.
- A clinical responsewith weight gain and resolution of symptoms when gluten is removed from the diet also helps confirm the diagnosis.
- Serum IgA-endomysial and serum tissue transglutaminase antibody testingare extremely sensitive and specific screens for celiac disease, except in individuals with IgA deficiency. Serum antigliadin IgG antibody testing is useful for patients who are IgA deficient.
- A strict gluten-free diet for lifeis necessary and results in complete reversal of intestinal damage. Vitamin and iron supplements may be required.
- Corticosteroids are used for severe diarrhea.
- Dietary changes in children often yield a rapid response, but noncompliance in adolescents is common and may lead to growth failureand delayed sexual maturity.
- Short Bowel Syndrome
- Definition.Patients with a shortened small intestine may have malabsorption resulting in malnutrition and compromised bowel function.
- Congenital lesions of the gut, such as gastroschisis, volvulus, or intestinal atresia, may require surgical resection of the small intestine resulting in an inadequate absorptive surface area.
- Infants who have undergone intestinal surgery for necrotizing enterocolitis may have short bowel syndrome.
- Crohn's disease, tumors, and radiation enteritis may also lead to short bowel syndrome.
- The absorptive capacity of the bowel depends on the length and location of the resected segment and on the condition of the residual gut.
- After gut resection, carbohydrate and fat malabsorptionwith steatorrhea are common.
- Dehydration, hyponatremia, and hypokalemia may all occur if resorptive capacity is limited.
- Distalsmall bowel resection (i.e., ileum) limits vitamin B12 and bile acid absorption.
- Clinical featuresinclude diarrhea, malabsorption, and FTT.
- Short bowel syndrome was formerly a fatal disorder. The development of total parenteral nutrition (TPN)now allows patients to maintain adequate nutrition and significantly improves survival.
- Early enteral feedingsare important to ensure adaptive growth of the remaining small bowel, proper hepatic function, and proper oral motor development.
- With proper management, patients may be able to wean off parenteral nutrition and survive. Adaptation of the intestine depends on the length and quality of the residual small bowel and on the presence of an intact ileocecal valve.
- Small bowel transplantationhas been performed but is reserved for patients with coexisting life-threatening TPN-associated liver disease. Liver transplantation may also be required.
- Complicationsinclude TPN cholestasis with resultant gallstones and cholestatic liver disease, intestinal bacterial overgrowth, nutritional deficiencies, poor bone mineralization and renal stones from hyperoxaluria, and secretory diarrhea as a result of the osmotic load on the remaining intestine.
III. Gastroesophageal Reflux
- Gastroesophageal reflux (GER)is the normal physiologic state in which stomach contents move retrograde into the esophagus.
- Gastroesophageal reflux disease (GERD)is a pathologic state associated with gastrointestinal (GI) or pulmonary symptoms and sequelae. Ten percent of infants with GER have GERD.
- Normal physiology
Normal periodic peristaltic waves of contraction of the esophagus transport ingested food into the stomach. The lower esophageal sphincter (LES) is a contracted circular muscle at the distal end of the esophagus that relaxes in a coordinated fashion with the peristaltic wave to allow esophageal contents to enter the stomach.
- Inappropriate transient lower esophageal sphincter relaxation (TLESR) is the predominant cause of GERD during childhood.Inappropriate TLESR allows excessive gastric refluxate to enter the esophagus and even the oropharynx. With time, prolonged contact of esophageal mucosa with gastric contents results in inflammation.
- Gastric emptying delaymay also play a role in GERD by increasing the quantity of gastric refluxate and by increasing gastric distension, which induces more TLESR.
- Clinical features of physiologic reflux (GER)
- Infants are termed “happy spitters”because they are without other
reflux-associated symptoms. Up to 60% of all infants have episodes of spitting up or vomiting not related to overfeeding or gastrointestinal disease.
- Emesis is benign, but often dramatic and traumatic for parents.
- Efforts at parental education and reassurance are vital. Avoidance of aimless formula changes, inappropriate early weaning, medications, homeopathic remedies, or costly seats, straps, and slings is the goal.
- Emesis generally resolves by 6–12 months of age.
- Clinical features of pathologic reflux (GERD)
- Infantsmay present with the following:
- Emesisis the most common presentation.
- Emesis may not always be present, or it may be so severe that it results in suboptimal calorie retention and FTT.
- Sandifer syndromeis a characteristic torticollis with arching of the back caused by painful esophagitis.
- Feeding refusalwith irritability or constant hunger may indicate esophagitis. The irritated esophagus may be painful, negatively reinforcing feeding, or the child may desire the buffering action of milk to reduce acid irritation.
- Older childrenusually present with the following:
- Symptoms of esophagitis, including midepigastric pain(“heartburn”) that is temporarily relieved with food or antacids and is exacerbated by fatty foods, caffeine, and the supine position.
- Associated symptoms include nausea (especially on awakening), hoarseness, halitosis, and wheezing.
- Sequelae of GERD
- Upper and lower airway diseasemay be induced or worsened by GERD. Acidic refluxate induces bronchopulmonary constriction and can also lead to frank aspiration or microaspiration. Common signs and symptoms include chronic laryngitis, hoarseness, wheezing, vocal cord nodules, and subglottic stenosis.
- Gastrointestinal sequelaeinclude FTT, esophageal strictures, and Barrett's esophagus (conversion of the normal stratified squamous epithelium of the esophagus into columnar epithelium; this condition may be associated with esophageal adenocarcinoma).
- Infants who remain symptomatic past 1 year of age and older children are unlikely to have spontaneous resolution of GERD and usually require long-term medical management or surgery.
Diagnostic evaluation focuses on ensuring normal anatomy and confirming any abnormalities.
- Barium upper gastrointestinal (UGI) studyexamines the anatomy of the esophagus, stomach, and duodenum. The UGI is a poor test for diagnosis of GERD, even if the refluxate is seen rising up to the oropharynx. Because TLESR is induced during administration of barium through a nasogastric tube, the sensitivity for GERD is high (85–90%) but the specificity is low (50%). Only frank aspiration of barium can be interpreted as GERD.
- Scintigraphyuses a radioactive marker (e.g., technetium 99m) mixed into age-appropriate foods to measure the rate of gastric emptying. When slow-decay markers are used, radioactive tracer detected in the lungs confirms aspiration.
- pH probe measurementis the gold standard for diagnosis.
- The pH of the esophagus is continuously monitored for at least 18 hours.
- Diagnosis of GERD is based on the number of acidification episodes, the total duration of esophageal acidification, and the time required for the pH to normalize in the presence of symptoms.
- To interpret the pH probe correctly, results should be correlated with the clinical presentation.
- Endoscopy with biopsyto detect inflammation may be indicated when the diagnosis is uncertain.
- Bronchoscopy with alveolar lavageis performed when aspiration is strongly suspected.
- Management Treatment
includes attempts at reducing entry of stomach contents into the esophagus and relieving symptoms.
- Conservative management
- Positioningin an upright or sitting position or raising the head of the bed after feedings or when asleep
- Dietaryrecommendations include frequent small meals and thickening of feeds using infant cereal or a commercial thickener, which attempts to hinder GERD by making the stomach contents more viscous. Acid inhibition with antacids, histamine H2-blockers, and proton pump inhibitors is effective in reducing the irritation caused by the refluxate.
- Motility agentsincrease the LES tone or increase gastric emptying. The most commonly used agent is metoclopramide, although side effects occur in up to one third of patients (e.g., drowsiness, restlessness, dystonic reactions).
- Surgerymay be required for patients who fail medical and conservative management.
- The Nissen fundoplicationwraps the fundus of the stomach around the distal 3.5 cm of esophagus, resulting in reduction of TLESR in as many as 90% of children.
- Gastric antroplasty may be performed to improve gastric emptying.
- In infants, placement of a gastrostomy tubeoften accompanies a Nissen fundoplication. Reduction in stomach volume by the Nissen procedure requires a period of adaptation and expansion of the stomach best assisted with tube feedings.
- Intestinal Anatomic Obstructions That Result in Vomiting
- Hypertrophic Pyloric Stenosis
- Definition.Thickening of the circular pylorus muscle results in gastric outlet obstruction with projectile vomiting.
- Incidence is 1 in 250 live births.
- Caucasiansand first-born male children are affected more commonly. The male-to-female ratio is 4:1.
- The etiology is unknown.Abnormal muscle innervation, breastfeeding, early administration of oral erythromycin, and decreased production of nitric oxide synthase have all been implicated.
- Associated conditions include duodenal atresia, tracheoesophageal fistula, trisomy 18, and Cornelia de Lange syndrome.
- Clinical features
- Vomiting of nonbilious, milky fluid starts during the second or third week of life.
- Vomiting becomes more forceful, is often described as projectile, and typically occurs immediately after feeding.
- Affected infants may be irritable but hungry.
- Jaundice occurs in 5% of patients, and it is associated with low levels of glucuronyl transferase enzyme.
- Dehydration from vomiting may occur.
- Physical examination
- The hypertrophied pylorus muscle may be palpable just above and to the right of the umbilicus. It is often referred to as the “olive.”
- Abdominal peristaltic waves may be visible after feeding.
- Prolonged vomiting of gastric contents classically results in hypochloremic, hypokalemic, metabolic alkalosis.
- Diagnostic studies
- Ultrasoundis able to measure the pylorus muscle length and thickness and is the diagnostic method of choice.
- UGImay demonstrate an elongated, narrow pyloric channel (“string sign”).
- Electrolyte abnormalities and dehydrationshould be corrected before surgery.
- Surgical correction is with a partial pyloromyotomy, in which the circular pylorus muscle fibers are transected.
- Malrotation and Midgut Volvulus
- Definition.Malrotation is an anatomic abnormality of intestinal rotation that allows the midgut to twist around the superior mesenteric vessels (i.e., volvulus). This may obstruct and infarct the bowel.
- Incidence of malrotation is 1 in 500 live births, with a 2:1 male predominance.
- Malrotation is common in patients with heterotaxy and may be associated with small bowel atresia, Hirschsprung's disease, and intussusception.
- Pathogenesis.The intestines normally return to the abdomen through the umbilical cord during the 10th week of gestation and undergo counterclockwise rotation about the axis of the superior mesenteric artery. The intestines are then fixed to the abdominal wall. Malrotation occurs when normal bowel rotation is interrupted.
- Lack of fixation of the small bowel results in peritoneal bands (Ladd's bands) that can compress the duodenum, causing mechanical obstruction.
- The narrow pedicle, which suspends the small bowel and the base of the superior mesenteric vessels, can easily twist, leading to ischemia and midgut volvulus.
- Clinical features
- Bilious vomitingand sudden onset of abdominal pain in an otherwise healthy infant are the classic presentation. Older children may have intermittent, crampy abdominal pain and vomiting.
- Anorexia, distension, and blood-tinged stools are common.
- Physical examination may be initially normal with peritonitis occurring later. Shock and cardiovascular collapse may occur as bowel ischemia progresses.
- Abdominal radiographsmay show gastric or proximal intestinal distension and obstruction, often with little or no distal bowel gas.
- Upper intestinal contrast imagingis the diagnostic tool of choice and shows abnormal position of the ligament of Treitz to the right of midline, partial or complete duodenal obstruction, and the jejunum to the right of midline.
- Lower intestinal contrast studiesmay reveal the cecum in the left abdomen or right upper quadrant.
- Volvulus is a surgical emergencyrequiring immediate exploration, untwisting of the gut, resection of any nonviable segments of intestine, and fixation of the gut to prevent recurrence.
- Fluid resuscitation, nasogastric suctioning, and broad-spectrum parenteral antibiotics should be administered.
- TPN may be required if a large segment of bowel is resected.
- Duodenal atresia and stenosis
- Definition.Duodenal atresia is a congenital obstruction of the duodenum caused by failure of the lumen to recanalize at 8–10 weeks gestation.
- Intestinal atresia is the most common cause of obstructionin the neonatal period.
- Incidence is approximately 1 in 10, 000 live births, with a male predominance.
- One fourth of cases occur in patients with Down syndrome.
- Clinical features
- Diagnosis may be suspected if prenatal ultrasound demonstrates gastric dilation with polyhydramnios.
- At birth, physical examination of patients with duodenal atresia may reveal a scaphoid abdomen with epigastric distension.Infants have feeding intolerance and vomiting.
- Duodenal stenosis may present with emesis, weight loss, and FTT.
- Other congenital defects (e.g., malrotation, esophageal atresia, congenital heart disease, renal anomalies) may also be present.
- Abdominal radiographyshows air in the stomach and proximal duodenum, creating a “double bubble” sign.
- Intestinal contrast studiesare very effective at diagnosing atresia and stenosis.
- Nasogastric decompression, hydration, and correction of electrolyte abnormalities (typically hypochloremic metabolic alkalosis) are necessary.
- Atresia is surgically corrected by duodenoduodenostomy.
- Exploration for malrotation and other luminal obstructions is also performed at the time of surgical correction.
- Jejunoileal atresia
- Definition.This congenital obstruction of the jejunum or ileum is caused by a mesenteric vascular accident during fetal life.
- Epidemiology.The incidence is approximately 1 in 3, 000 live births. It is not usually associated with other anomalies.
- Clinical features.Bilious emesis and abdominal distension occur within the first few days of life.
- Evaluation.Abdominal radiographs reveal air-fluid levels, and contrast studies reveal the atresia.
- Management.Patients should receive nasogastric suctioning and fluid resuscitation before surgical resection and anastomosis of the atretic segment of small bowel.
- Definition.Intussusception is the telescoping or invagination of a more proximal portion of intestine into a more distal portion.
- Epidemiology.The incidence is 1.5–4 in 1, 000 live births, with a slight male predominance. Peak incidence occurs at 5–9 months of age. It is the most common cause of bowel obstruction after the neonatal period in infants less than 2 years of age.
- Pathogenesis and etiology
- Intussusception may occur at a variety of sites within the intestine, but ileocolic intussusception is the most common location.
- Etiology is generally unknown, but a lead pointsuch as Meckel's diverticulum, polyp, intestinal duplication, Peyer's patch, or lymphoma may act to draw the proximal intestine inward. However, a lead point is identified in only 5% of cases and is more common in older children.
- Intussusception causes bowel wall edema and hemorrhage and may lead to bowel ischemia and infarction.
- Clinical features
- Previously healthy infants or children may present with sudden onset of crampy or colicky abdominal pain.The pain often occurs in intervals followed by periods of calm. Infants may cry and draw their legs toward the chest.
- Vomiting and lethargy are common.
- Stools may be normal or have a bloody, “currant jelly”appearance because of intestinal ischemia and mucosal sloughing.
- Occasionally, a sausage-shaped massmay be palpated in the abdominal right upper quadrant, representing the intussusception.
- Initial management should include fluid resuscitation.
- Radiographs are of limited usefulness but may reveal dilated loops of bowel, or pneumoperitoneum if perforation has occurred.
- Abdominal ultrasound may be a useful diagnostic tool, but air or contrast enema(barium or Gastrografin) remains the gold standard, both to establish the diagnosis and to reduce the intussusception. (Contrast enema may show the classic “coil spring” sign representing the intussusception.)
- Contrast enemaswith air or hydrostatic pressure successfully reduce the intussusception in 80–90% of cases.
- If the contrast enema fails to reduce the intussusception, or if the child has signs of peritonitis or pneumoperitoneum, operative reductionis indicated.
- The risk of recurrenceis 5% after contrast reduction and 1% after surgical repair.
- Hirschsprung's disease
This disorder may also cause vomiting and is described in Chapter 4, section XII.D.4.
- Acute Abdominal Pain
- General Concepts
- Definition.The term acute abdomen describes the sudden onset of abdominal pain that requires urgent evaluation, diagnosis, and treatment. Although most acute abdominal pain is self-limited, the pain may result from a serious medical or surgical cause and may require prompt surgical evaluation.
- Etiology (Figure 10-1)
- Complete history, specifically including assessment for recent trauma, prior abdominal pain or surgery, infections, and medications. Review of systemsshould focus on associated symptoms of fever,
vomiting, diarrhea, constipation, anorexia, dysuria, or worsening pain with eating. The timing of symptoms may provide key diagnostic information.
Figure 10-1. Etiology of acute abdominal pain during childhood.
- Physical examinationshould include evaluations of the abdomen, chest, back, head and neck, and genitourinary system.
- General assessment.Restlessness may indicate colicky pain. Abdominal rigidity is seen with a peritoneal process. Constant pain suggests strangulation of the gut or torsion.
- Abdominal examination
- Intestinal obstructionmay present with high-pitched bowel sounds, abdominal distension, tenderness, and, at times, visible peristalsis.
- Peritonitispresents with diminished or absent bowel sounds, abdominal wall rigidity, involuntary guarding, and often rebound tenderness.
- Accessory tests
- Imaging studiesmay include abdominal radiography to identify obstruction, mass, or free air; ultrasound for evaluation of viscera and fluid; and CT scan (often with oral, intravenous, and/or rectal contrast) to visualize abdominal anatomy and pathology.
- Laboratory evaluationshould include a CBC, urinalysis, and
metabolic panel. Hepatic function tests, amylase and lipase, and testing for pregnancy and sexually transmitted diseases should be performed, if indicated.
- Specific Causes of Abdominal Pain
- Definition.Appendicitis is obstruction and inflammation of the appendix.
- Epidemiology.Appendectomy is the most common pediatric emergency operation. Peak incidence is 10–12 years of age.
- Pathophysiology.The lumen of the appendix is obstructed by either a fecalith or by lymphoid tissue causing appendiceal distension and ischemia. This distension produces visceral pain referred to the T-10 dermatome or periumbilical region and the release of inflammatory mediators. Without surgical intervention, this process usually leads to perforation within 36 to 48 hours.
- Clinical features
- Symptomsusually begin with periumbilical pain, followed by vomiting. Within hours, the pain usually localizes to the right lower quadrant. Fever and anorexia are usually present.
- Physical examinationclassically demonstrates tenderness to palpation at McBurney's point (an area two thirds of the way from the umbilicus to the anterior superior iliac spine). Voluntary guarding may progress to involuntary guarding and rebound tenderness as peritoneal irritation increases.
- Laboratory findingsinclude leukocytosis with a polymorphonuclear predominance.
- Diagnosismay be difficult in children, which contributes to a high rate of perforation (20–50%). Although abdominal ultrasound or CT often aids in diagnosis, the patient may undergo an appendectomy without having a definitive diagnosis in an attempt to prevent perforation.
- Managementconsists of fluid resuscitation, preioperative antibiotics, and an appendectomy, often by laparoscopy. Perforated appendicitis requires drainage of purulent material, irrigation of the peritoneal cavity, and parenteral antibiotics.
- Acute pancreatitis
- Definition.Pancreatitis is an acute inflammatory process of the pancreas that may involve peripancreatic tissues and other organ systems.
- Epidemiology.Pancreatitis is uncommon in children.
- Pathophysiology.An initial insult, such as ductal obstruction or viral infection, causes premature activation of pancreatic proenzymes and autodigestion of pancreatic cells. Inflammatory mediators and cytokines damage the pancreas and cause interstitial edema and necrosis. Necrosis of blood vessels may lead to parenchymal hemorrhage.
- Etiology. Causesinclude blunt trauma (most common), infections (e.g., mumps, enterovirus, Epstein-Barr virus [EBV], HIV, hepatitis A and B), drugs and toxins, congenital anomalies, and obstruction.
Less commonly, acute pancreatitis may be the result of a systemic illness, such as systemic lupus erythematosus or cystic fibrosis. Idiopathic pancreatitis accounts for up to 25% of cases in children and is the second most common cause of pancreatitis during childhood.
- Clinical features
- Abdominal pain occurs in the periumbilical or epigastric areaand may radiate to the back.
- Fever, anorexia, nausea, and vomiting are common.
- Physical examination reveals epigastric tenderness, abdominal distension, and decreased bowel sounds. Gray-Turner sign(bluish discoloration of the flanks) or Cullen sign(bluish discoloration of the periumbilical area) may be present in severe cases and is caused by blood tracking along fascial planes.
- Hypotension, tachycardia, hypoxia, and capillary leak may be seen in severe, acute hemorrhagic pancreatitis.
- Serum amylaselevels rise within hours of pain onset and remain elevated for 4–5 days. Serum lipase level elevation is more specific for acute pancreatitis and remains elevated longer than serum amylase levels.
- Other laboratory abnormalitiesmay include leukocytosis, hyperglycemia, hypocalcemia, elevated transaminases, and coagulopathy.
- Abdominal ultrasoundis the most common method used for diagnosing and monitoring acute pancreatitis. Abdominal CT is useful in diagnosing complications, such aspseudocyst, abscess, or necrosis.
- Supportive careincludes bed rest, hydration, electrolyte correction, analgesia, and nasogastric suctioning. Oral feedings usually are restricted to minimize pancreatic stimulation.
- TPNis essential to prevent protein catabolism because some patients may not be able to tolerate oral feedings for weeks.
- Antibioticsare indicated for severe, acute necrotizing pancreatitis.
- Surgeryto remove necrotic tissue within and around the pancreas may be indicated. However, surgical intervention for early, acute pancreatitis is controversial.
- Complications.Conditions include respiratory insufficiency and acute respiratory distress syndrome (ARDS), renal failure, shock, and gastrointestinal bleeding. A pseudocyst(collection of fluid rich in pancreatic enzymes that arises from pancreatic tissue) may develop. A small pseudocyst resolves on its own; however, a large, persistent pseudocyst may require surgical drainage.
- Definition.Inflammation of the gallbladder with transmural edema that may be associated with gallstones, or less commonly, without stones (termed acute acalculous cholecystitis).
- Epidemiology.In contrast to adults, acute cholecystitis is uncommon in healthy children. However, it may occur in children with predisposing conditions such as sickle cell disease, cystic fibrosis, or prolonged TPN therapy.
- Pathophysiology and etiology
- Obstruction of the cystic duct causes increased intraluminal pressure and distension, increased secretion of enzymes and prostaglandins, and progressive inflammation. Infection, necrosis, and perforation may all occur.
- Acute acalculous cholecystitis is usually caused by infection (e.g., Salmonella, Shigella, Escherichia coli) but may also be seen after abdominal trauma, burns, or vasculitis.
- Clinical features
- Abdominal pain is initially diffuse but eventually worsens and localizes to the right upper quadrant.
- Fever, anorexia, and vomiting are common.
- Jaundice may be a late finding.
- Physical examination may reveal Murphy's sign(i.e., palpation of the right upper quadrant during inspiration elicits intense pain and causes the patient to stop inspiratory effort). Guarding and peritoneal signs may also be present.
- Diagnosis is confirmed by abdominal ultrasound, which can detect stones and a thickened gallbladder wall.
- Cholescintigraphymay be useful.
- Laboratory findings may include mild elevations of bilirubin and serum transaminases.
- Management.Treatment includes fluid resuscitation, parenteral antibiotics, and analgesia. If the disease progresses or if peritonitis develops, cholecystectomy is indicated. This procedure is often performed laparoscopically and may be done electively after the acute episode resolves.
- Chronic Abdominal Pain
- Definitions Chronic abdominal pain (CAP)
is defined as abdominal pain that occurs each month for at least 3 consecutive months.
- Organic(caused by a disease process or disorder; one third of cases)
- Nonorganic (functional;two thirds of cases). Functional CAP occurs more commonly in females.
CAP occurs in 20–40% of children and adolescents.
- Organic CAP (Table 10-2)
- Nonorganic CAP. Note:It is important to understand that the patient senses real pain, even in the absence of an underlying organic cause.
- Classification is based on clinical features.
- Epigastric pain, associated with belching, bloating, nausea, vomiting, and early satiety, is the childhood equivalent of nonulcer dyspepsiain adults.
Table 10-2. Organic Causes of Chronic Abdominal Pain
- Periumbilical painrepresents classic functional abdominal pain (FAP). FAP is most likely in a child older than 5 years of age.
- The pain may be varied in character, including paroxysmal, dull, sharp, or cramping.
- The pain confers secondary gain, does not interfere with pleasurable activities or sleep, and has no consistent temporal correlation to activity, meals, or bowel patterns.
- Infraumbilical pain, associated with abdominal cramping, bloating, and alterations in stool, is the childhood equivalent of irritable bowel syndromein adults.
- Etiology.Although the cause in unknown, the following are risk factors that predispose to the development of nonorganic CAP:
- Psychosocial risk factorsinclude personality (e.g., timid, nervous, anxious, overachiever), birth order (e.g., first-born and last-born), life stressors, including change in daily routine (e.g., nanny, change in school), family stressors (e.g., divorce, separation, parental fighting), and methods of discipline that are either too extreme or submissive.
- Risk factors relating to family history include alcoholism, antisocial or conduct disorders, attention deficit hyperactivity disorder, and family members with functional pain syndromes (e.g., headaches, CAP, musculoskeletal pain).
- Risk factors relating to past medical history
- Maternal:pregnancy problems, intrapartum problems (e.g., labor difficulties, cesarean section)
- Child:neonatal problems (e.g., colic), childhood problems (e.g., enuresis, nightmares)
- Some children also have minor GI disturbancesin motility or in their sympathetic or parasympathetic nervous systems that make them susceptible to risk factors for nonorganic CAP.
A detailed history focusing on symptoms and risk factors for nonorganic CAP, and a comprehensive physical examination with special attention to the abdominal and genitourinary systems are necessary to exclude
organic disease. The healthier the child appears, the more likely the pain is functional.
- Laboratory evaluationshould be tempered and based on examination or clinical symptoms.
- Screening laboratoriesinclude CBC, electrolytes, liver function panel, stool for occult blood, stool for parasite screening, and erythrocyte sedimentation rate (ESR) or C-reactive protein.
- Screening for Helicobacter pylorishould be reserved for children with symptoms of dyspepsia because the asymptomatic carriage rate of H. pylori is high during childhood.
- Lactose breath hydrogen testingto rule out lactose intolerance is a reasonable option because lactose intolerance may be present in as many as 10% of otherwise asymptomatic children.
- Radiographic studiesare not routinely indicated unless warranted by the history or physical examination.
- Organic CAPis treated on the basis of the specific diagnosis.
- Goals of therapyinclude normalization of the child's activities, education of parents as to the nature of the disorder, and development of methods to empower the child and family to control the discomfort.
- Family and individual counselingare usually necessary.
- Symptomatic medications, such as antispasmodics, sedatives, or analgesics, are ineffective.
Long-term prognosis of FAP is poor. Only 50% of patients have complete symptom resolution during childhood, and at least 25% of patients have abdominal pain as adults. Poor prognostic factors include male gender, age of onset < 6 years, duration of symptoms > 6 months, maximum parental education less than high school, lower socioeconomic status, a history of abdominal operations, and having unresolved family issues.
VII. Constipation and Encopresis
- Constipationis defined as a reduction in defecation that causes adverse symptoms that may include difficult defecation, painful defecation, abdominal discomfort, and stool retention. Stools are often dry and hard.
- Encopresisis defined as the developmentally inappropriate release of stool, unrelated to an organic etiology. Encopresis is almost always associated with severe constipation:liquid stool leaks around a hard, retained stool mass and is involuntarily released through the distended anorectal canal.
- Constipation is very commonduring childhood.
- Age of onset usually occurs during infancy for organic causes of constipation, and after toilet training for functional constipation.
- Encopresis is seen predominantly in males.
- Normal stool patterns
Normal defecation frequency varies with age with an adult pattern developed by 4 years of age.
- Frequency averages 4×/day during the first week of life, 2×/day by 1 year of age, and 1×/day by 4 years of age.
- Adult defecation ranges from 3×/day to 3×/week.
- Breastfed infants defecate more frequentlyduring the first months of life; however, this decreases rapidly so that there is no difference in stool pattern between breastfed and formula-fed infants by 4 months of age.
Constipation may be functional or organic.
- Functional fecal retention (FFR)is the most common form of constipation during childhood and results from inappropriate constriction of the external anal sphincter.
- Pathophysiology and etiology
- Infants and toddlers may inappropriately retain stool as a result of traumatic events(e.g., hard stool, painful diarrhea, diaper rash, physical abuse) leading to a self-fulfilling cycle of increased fecal mass, fecal hardness, and painful defecation.
- Although behavioralin pathophysiology, some FFR patients also have subclinical disturbances in the defecation process predisposing them to constipation.
- Clinical features.FFR becomes a behavioral pattern of stool withholding that may lead to large amounts of retained feces with secondary anorectal distension, encopresis, fecal halitosis, abdominal distension and pain, anorexia, urinary tract problems (from pelvic displacement), and psychosocial problems.
- Organic causesrepresent fewer than 5% of cases of childhood constipation and are usually present early in infancy.
- Hirschsprung's diseaseis the most common cause of organic constipation in an otherwise healthy child (see Chapter 4, section XII.D.4 for details).
- Table 10-3 lists other organic causes of constipation.
It is necessary to focus on determining whether organic constipation or FFR exists. While FFR is the most likely cause, a thorough history and physical examination (including a complete neurologic examination) must be conducted to identify the presence of an organic etiology.
- Delayed meconium passage (> 48 hours after birth), onset of constipation during infancy, history of pelvic surgery, encopresis before 3 years of age, and inability to toilet train all suggest an organic cause.
- Development of constipation after toilet training, identification of a sentinel event(e.g., diarrhea, change in psychosocial environment, inappropriate toilet training methods, abuse) with continued normal growth and development all suggest FFR.
Table 10-3. Organic Causes of Constipation
- Diagnostic studiesare only necessary when organic disease is suspected, or if the patient with FFR is failing management. Radiographic studies may include a barium enema, rectal biopsy to rule out Hirschsprung's disease, and manometry studies.
Treatment is based on the suspected cause.
- Mild, episodic constipation can usually be addressed by ensuring the diet contains adequate soluble fibersand by increasing the amount of water and sorbitol-containing juices.
- FFR management is based on cleaning out the fecal mass, softening the stool, and educatingthe patient and family.
- Stool evacuationis necessary to begin recovery and is performed using high-dose mineral oil, polyethylene glycol solutions, enemas, or manual disimpaction.
- Maintenance therapymost often includes mineral oil to soften and lubricate the stool.
- Education is the most important intervention.Emphasis is placed on identification and correction of triggers, creation of a regular toilet schedule, removal of negative reinforcements, and creation of a positive environment. Individual and family counseling may be helpful.
(see Chapter 7, section XI)
- Inflammatory Bowel Disease (IBD)
This group of chronic, inflammatory gastrointestinal disorders includes ulcerative colitis (UC) and Crohn's disease (CD) and is characterized by exacerbations and remissions.
- The age of onset is bimodal, with a peak at 15–20 years of age and a second peak after 50 years of age.
- IBD is increasing in frequency in children, with 25–30% of all cases of CD and 20% of UC cases presenting before 20 years of age.
- Four percent of patients present before 5 years of age.
- Males and females appear equally affected by UC, but there is a 2:1 male-to-female ratio in CD.
- Positive family history for IBD is found in approximately 15–20% of patients.
- Clinical Features
- Ulcerative colitis (Table 10-4)
- Inflammation is diffuse, limited to the mucosa, and localized to the colon.UC usually begins in the rectum and extends proximally in a contiguous fashion.
- Disease of the rectum only is called ulcerative proctitis.
- Disease affecting the entire colon is known as pancolitis.
- Mild disease, seen in 60% of cases, presents with rectal bleeding, diarrhea, and abdominal pain.
- Moderate disease, seen in 30% of cases, presents with nocturnal stooling, cramping, and tenesmus. Systemic symptomsof weight loss, anorexia, fever, and anemia also occur.
- Severe disease, seen in 10% of cases, presents with more than six stools per day, fever, anemia, leukocytosis, and hypoalbuminemia.
- Extraintestinal manifestationsare less common during childhood (Table 10-4).
- Complicationsof severe UC
- Toxic megacolon.This severe inflammation of the colon leads to decreased intestinal motility, disruption of the mucosal barrier which allows bacteria to enter, and colonic dilatation. Patients present with fever, abdominal distension, and septic shock, and they are at risk for perforation and hemorrhage.
- Increased risk of colon cancer
- Crohn's disease (Table 10-4)
- CD may involve any segment of the gastrointestinal tract, from the mouth to anus.
- Unlike UC, the inflammation is eccentric and segmentalwith “skip lesions.”
- Inflammation is transmuraland may lead to sinus tracts, fistulas, and crypt abscesses.
- Most children have disease involving the terminal ileum.
- Intestinal symptoms include abdominal pain, postprandial cramping, diarrhea, and anorexia.
- Initial symptoms may be subtle, with abdominal pain or decreased growth the only findings.
- Small bowel disease often leads to malabsorptionwith resultant iron, zinc, folate, and vitamin B12 deficiencies.
- Perianal diseaseoften precedes the development of intestinal disease and presents with skin tags, fissures, fistulas, and abscesses.
Table 10-4. Differentiation of Ulcerative Colitis and Crohn's Disease
- Extraintestinal complications are more commonthan in UC and are noted in Table 10-4.
- Complicationsare caused by the transmural nature of CD and include abscesses, fistulas, strictures, and adhesions.
- CD is a chronicdisorder with high morbidity but low mortality. Patients are prone to frequent exacerbations despite treatment.
In addition to a history and physical examination, the following are generally indicated:
- Laboratory analyses
- CBCoften shows anemia or leukocytosis.
- ESRis usually elevated.
- Serum albuminand serum transaminases to assess nutritional status and liver disease
- Serum antibody testsmay help establish a diagnosis (see Table 10-4).
- Stool studiesshould be performed to rule out infectious enteropathies.
- Abdominal ultrasoundand CT imaging can be used to visualize abscesses and thickened bowel walls. UGI with small bowel follow through can reveal mucosal ulcerations, narrowed lumens, thickened walls, and fistulas.
- Colonoscopy with biopsiesof the colon and terminal ileum confirms the diagnosis.
principles include controlling symptoms, reducing recurrences, and optimizing nutrition.
- Sulfasalazineis effective for mild disease, especially for UC, and can also prevent relapses.
- Corticosteroidsare often given to calm acute exacerbations and induce remission.
- Immunosuppressive agentsare useful in inducing long-term remission.
- Metronidazoleis used in the treatment of CD, especially for perianal involvement.
- UC can be cured with a total proctocolectomy, but this is reserved for intractable colitis.
- Surgical therapy for CD is only considered for persistent bleeding, abscesses, and fistulas that do not respond to medical therapy. Recurrence rate is high after bowel resection.
- Nutrition.Total parenteral nutrition may be necessary during flare-ups to ensure adequate growth and healing.
- Gastrointestinal Bleeding
Blood loss from the GI tract may occur in several ways, and the presentation may help determine origin of the bleeding.
- Hematemesisis the vomiting of fresh or old blood, which may have a “coffee ground” appearance from the denaturing of hemoglobin.
- Hematocheziais bright red blood passed per rectum, usually indicating a lower GI source or a significant rapid bleed from an upper lesion.
- Melenais dark, tarry stools and often indicates an upper GI bleed proximal to the ligament of Treitz.
- Laboratory confirmation of GI bleeding
Occult bleeding from the GI tract is confirmed by positive guaiac testing of stool. Guaiac is a colorless dye that changes color from the peroxidase activity of hemoglobin in the presence of hydrogen peroxide developer.
- False-positiveresults may occur because of ingested iron, rare red meats, beets, and foods with a high peroxidase content, such as cantaloupe, broccoli, and cauliflower.
- False-negativeresults may occur as a result of large ingested doses of vitamin C.
- Upper GI Bleeding
- Newborns may swallow maternal bloodduring delivery or while nursing from a bleeding nipple. Older children may swallow blood during an episode of epistaxis and can present with emesis that mimics a GI bleed.
- Gastritis or ulcersmay occur as a result of severe stress of illness, surgery or burns, or from medications. Ulcers may also develop in children with H. pylori infection.
- Mechanical injury to the mucosa from vomiting (i.e., Mallory-Weiss tear) or from foreign body or caustic ingestion may cause upper GI bleeding.
- Varicesas a result of portal hypertension or vascular malformations are less common causes.
- Initial assessment must include a detailed history and physical examination.
- Particular attention must be given to the patient's hemodynamic status.
- Ongoing bleeding is assessed by obtaining a nasogastric tube aspiratefor fresh blood.
- Nose and oropharynxshould be inspected for non-GI sources of bleeding.
- Laboratory studiesshould include hemoglobin and platelet counts, coagulation studies, serum transaminases, and a blood urea nitrogen (BUN) level (suggests GI bleed if elevated). Patients with active bleeding or hemodynamic changes should have blood sent for type and crossmatch.
- Plain film radiographyhas a limited role in diagnosis but may be useful if a foreign body or perforation is suspected.
- Upper intestinal endoscopyfor diagnosis and management is indicated for active bleeding with hemodynamic changes.
- Initial stabilizationof hypovolemia and anemia is essential. Intravenous access with two large-bore peripheral lines should be established, and a rapid fluid bolus of 20 mL/kg of normal saline solution should be given as needed. (See Chapter 20, section II.D for a discussion of the management of shock.)
- Medical therapyto control UGI bleeding may be useful. Octreotide (vasopressin) can be used to vasoconstrict varices. Ulcers associated with H. pylori should be treated with appropriate antibiotic therapy. Gastritis, esophagitis, and ulcers should also be treated with methods to decrease acid production, such as H2-blockers or proton pump inhibitors.
- Endoscopic therapy(e.g., photocoagulation, banding, vessel ligation, injection with sclerosing agents) is indicated for active bleeding or if rebleeding is very likely.
- Arteriographic embolizationmay be used for serious bleeding from vascular malformations.
- Surgical treatmentis usually indicated for duodenal ulcers with active arterial bleeding, perforation, or varices.
- Lower GI Bleeding
- Age is an important factor in determining the cause of lower GI bleeding (Table 10-5).
- Necrotizing enterocolitisshould be considered in any newborn who presents with rectal bleeding, feeding intolerance, or abdominal distension (see Chapter 4, section XII.E).
Table 10-5. Differential Diagnosis of Lower Gastrointestinal Bleeding
- Juvenile polypsare the most common cause of significant lower GI bleeding beyond infancy. Bleeding is painless, intermittent, and often streaky. Colonoscopy with polypectomy is the definitive treatment.
- Hirschsprung's diseasemay present with colitis and abdominal distension.
- Allergic colitisfrom sensitization to protein antigens in cow's milk, soy milk, or breast milk may develop in neonates and infants.
- Infectious enterocolitisfrom bacterial pathogens such as Salmonella, Shigella, Campylobacter, Yersinia, and E. coli can occur at any age (see Chapter 7, Table 7-6).
- Meckel's diverticulumis an outpouching of the bowel in the terminal ileum that occurs in 2% of infants. It is an important cause of lower GI bleeding in infants and children. The diverticulum contains ectopic gastric mucosa that produces acid. This acid damages adjacent intestinal mucosa, causing the classic presentation of painless, acute rectal bleeding in an otherwise healthy child. A nuclear medicine scan identifies the ectopic gastric mucosa, and surgical resection is required.
- Ischemic diseases and vasculitis can also cause lower GI bleeding.
- Hemolytic uremic syndromeis a vasculitis characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Intestinal ulceration and infarction of the bowel cause bleeding (see Chapter 11, section VI).
- Henoch-Schönlein purpurais an IgA-mediated vasculitis that presents with a palpable, purpuric rash on the buttocks and lower extremities, large joint arthralgias, renal involvement, and GI bleeding from complications such as intussusception and bowel perforation (see Chapter 11, section IV.F.3 and Chapter 16, section I).
- Inflammatory bowel diseaseis an important cause of occult and frank GI bleeding.
- Evaluation and management.As with upper GI bleeding, assessment of hemodynamic status, monitoring for ongoing bleeding, and stabilization are essential. Laboratory studies, intravenous access, and fluid resuscitation are indicated as for upper GI bleeding. Specific management is based on the identified cause.
- Liver Abnormalities and Hepatitis
- General Concepts
- Hepatic injury
- Direct hepatocellular damage or damage to the biliary system results in derangements in the liver's synthetic ability, excretory function, or detoxification.
- Cellular damage also leads to the release of intracellular enzymes characteristic of the originating cell.
- Obstruction or damage to the biliary system causes retention of bile enzymes that damage the cells lining the biliary tree and hepatocytes.
- Laboratory assessment of liver injury and function
- Hepatocellular enzymes
- Aspartate aminotransferase (AST)elevation is a sensitive but nonspecific marker of hepatocyte injury. AST is also found in skeletal muscle, red blood cells, and cardiac tissue.
- Alanine aminotransferase (ALT)elevation is a very specific marker of liver disease.
- Lactate dehydrogenase (LDH)elevation is nonspecific for liver disease, although it may serve as a marker for hepatocellular necrosis.
- Biliary enzymes
- Alkaline phosphatasemay be elevated in biliary disease, although it may also be elevated in children because of rapid growth, in bone, kidney, and intestinal disease, and in trauma.
- Gamma glutamyl transpeptidase (GGTP) and 5′-nucleotidase (5NT) are also elevated in biliary disease. 5NT is more specific than GGTP for biliary tract damage.
- Bilirubinis derived from the breakdown of heme.
- Unconjugated (indirect) bilirubinis combined with glucuronide by the enzyme UDP-glucuronyl transferase in the liver to form mono- and di-conjugates (conjugated or direct bilirubin).
- Elevated bilirubinmay be a consequence of increased heme load (e.g., hemolysis, polycythemia, hematoma), decreased capacity for excretion (e.g., hepatitis, liver failure), or obstruction to bile flow (e.g., biliary atresia, choledochal cyst).
- Synthetic functionis assessed by evaluating protein production (e.g., prealbumin, albumin, and prothrombin time), serum chemistries (e.g., glucose, cholesterol), and toxin clearance (e.g., lactate, ammonia).
- Infant Jaundice
(Neonatal jaundice is discussed in Chapter 4, section X.)
- Infant jaundiceis defined as elevated bilirubin after the neonate period and within the first year of life. Bilirubin collects in the skin, conjunctiva, and mucous membranes and becomes evident clinically when the total bilirubin level exceeds 3 mg/dL.
- Cholestatic jaundiceis defined as retention of bile within the liver and occurs clinically when the direct component of bilirubin is > 2 mg/dL or ≥ 15% of the total bilirubin.
- As many as 50% of all neonates or infants experience transient jaundice, the majority of whom have unconjugated (indirect) hyperbilirubinemia.
- Conjugated (direct) hyperbilirubinemiais a marker for cholestasis. Cholestasis occurs in 1 in 10, 000–15, 000 live births, and more
than 50% are caused by neonatal hepatitis or biliary atresia (see section XI.D.2.3).
- Clinical features
- Jaundice typically begins cranially and extends caudallyas bilirubin increases.
- Infants often appear otherwise well.
- Evaluation.It is important to focus on establishing whether cholestasis exists and whether the problem is isolated to the liver.
- Historyshould focus on timing of jaundice onset, associated symptoms (e.g., poor growth, bleeding, dark urine), feeding regimen (e.g., breast or bottle, frequency of feedings), and stool quality and color.
- Past medical historyshould include prenatal history, medications, infections, and family history of liver disease or jaundice.
- Physical examinationshould be comprehensive.
- Laboratory evaluationshould initially include CBC, electrolytes, and assessments of hepatic function. Further testing is directed on the basis of clinical suspicions. It is difficult to predict the level of bilirubin from the extent of jaundice on physical examination. Measurement of direct and total bilirubin is therefore necessary in all patients with suspected jaundice.
- Imagingoften includes abdominal ultrasound with Doppler evaluation of the hepatic vessels. Radionucleotide imaging (e.g., hepatobiliary iminodiacetic acid [HIDA] scan) of the biliary tree is warranted in suspected cholestasis.
- Liver biopsyis invasive and is reserved for confirmation of diagnosis, assessment for hepatic injury, or when the evaluation remains inconclusive.
- Categories of jaundice
- The differential diagnosis of unconjugated hyperbilirubinemiais presented in Chapter 4, section X.C and Figure 4-2. Two additional causes of unconjugated hyperbilirubinemia are worth noting.
- Inspissated bile syndromeis associated with hemolysis (e.g., ABO incompatibility) or with a very large hematoma. In these cases, the biliary system becomes overwhelmed by the increased bilirubin load. Although unconjugated hyperbilirubinemia predominates early, conjugated hyperbilirubinemia eventually develops as hepatocellular function increases to meet demand.
- UDP-glucuronyl transferase deficiencycan present in three distinct states.
- Gilbert's syndrome, in which 50% of enzyme activity is absent. Mildunconjugated bilirubinemia occurs associated with stress or poor nutrition.
- Crigler-Najjar type 1is an autosomal recessive disorder in which almost 100% of enzyme activity is absent. Kernicterus caused by extremely high bilirubin levels occurs almost universally.
- Crigler-Najjar type 2is an autosomal dominant disorder
in which 90% of enzyme activity is absent. Bilirubin levels are more variable with a lower likelihood of kernicterus.
- The differential diagnosis of conjugated hyperbilirubinemiais presented in Chapter 4, section X.D and Figure 4-3.
- Cholestatic Diseases of Infancy
- General concepts
- Cholestasis is characterized by retention of bile within the liver with prolonged elevation of conjugated (direct) bilirubin.
- Infections(e.g., sepsis, hepatitis, viral infections)
- Metabolic derangements(e.g., cystic fibrosis, hypothyroidism, galactosemia)
- Extrahepatic mechanical obstruction(e.g., biliary atresia, bile duct stricture)
- Intrahepatic mechanical obstruction(e.g., paucity of intrahepatic bile ducts, Alagille syndrome)
- Idiopathic(e.g., neonatal hepatitis)
- α1-Antitrypsin deficiency
- TPN-associated disease
- Clinical features of cholestasis
- Acholic or light stools
- Dark urine
- Bleeding(occurs as a result of prolongation of the prothrombin time as a result of diminished hepatic synthetic function)
- Neonatal hepatitis
- Definition.Neonatal hepatitis is idiopathic hepatic inflammation during the neonatal period. It is a diagnosis of exclusion and is the most common cause of cholestasis in the newborn.
- Epidemiology.Incidence is 1 in 5, 000–10, 000 live births, with a male predisposition.
- Clinical features
- Symptoms may rangefrom transient jaundice and acholic stools to liver failure, cirrhosis, and portal hypertension.
- Presenting features in the first week of life include jaundice and hepatomegaly in 50% of patients.FTT and more significant liver disease occur later in infancy in 33% of patients.
- The course of disease is generally self-limited, with full recovery during infancy in as many as 70% of patients.
- Diagnosisis on the basis of clinical presentation, results of liver biopsy, and exclusion of other causes of cholestasis.
- Management is supportive.
- Decreased fat absorption may lead to growth failure and vitamin
deficiencies. Increased nutritional support with concentrated calories, use of medium-chain triglyceride–containing formulas, and provision of fat-soluble vitamins A, D, E, and K are indicated. TPN may be needed if growth remains problematic.
- Ursodeoxycholic acid, a bile acid, is used to enhance bile flow and to reduce bile viscosity. Ursodeoxycholic acid is not used until biliary obstruction has been excluded as a possibility.
- Liver transplantationmay be necessary in cases of severe liver failure.
- Biliary atresia (BA)
- Definition.BA is a progressive fibrosclerotic disease that affects the extrahepatic biliary tree. Fifty percent of all pediatric liver transplants are performed for liver failure caused by BA.
- Epidemiology.Incidence is 1 in 10, 000 live births.
- Etiology is unknown.
- Clinical features
- Two thirds of patients present between the ages of 4 and 6 weekswith jaundice, dark urine, and pale or acholic stools. The remaining one third of patients present earlier, within the first 2 weeks of life, and therefore the presentation can be confused with physiologic jaundice.
- Bilirubin levels are moderately elevated.
- Progression of disease is rapid, with bile duct obliteration and cirrhosis occurring by 4 months of age.
- Other signs and symptoms include hepatosplenomegaly, ascites, poor growth, steatorrhea, peripheral edema, and coagulopathy.
- Some infants have an associated polysplenia syndromewith bilobed lungs, abdominal heterotaxia, and situs ambiguous. These patients present earlier and progress more rapidly.
- Diagnosismust be rapid to affect outcome.
- Abdominal ultrasound, radionucleotide imaging, and liver biopsy are performed in rapid sequence to rule out other causes of cholestasis.
- Intraoperative cholangiogram with laparotomy to examine the biliary tree confirms the diagnosis.
- Managementfocuses on supportive care and reestablishing bile duct continuity.
- Kasai portoenterostomy(Roux-en-Y intestinal loop attached directly to the porta hepatis) is the treatment of choice to establish bile flow; however, its success diminishes rapidly with increasing patient age at presentation. Success is highest if the procedure is performed by 50–70 days of age. Cholangitis is a worrisome complication of the procedure that occurs in as many as 50% of patients, and repeated episodes can stop all bile flow.
- Liver transplantationis indicated for liver failure and late clinical presentations.
- Supportive careincludes nutrition, fat-soluble vitamin supplementation, and, once bile flow is reestablished, ursodeoxycholic acid.
- Alagille syndrome
- Definition.This autosomal dominant disorder is characterized by paucity of intrahepatic bile ducts and multiorgan involvement.
- Epidemiology.Incidence is 1 in 70, 000 live births. Two thirds of patients have an abnormality on chromosome 20 affecting the jagged 1 gene.
- Clinical features
- Features of cholestatic liver diseaseare indistinguishable from neonatal hepatitis and BA. Of note, pruritus in these patients can be debilitating.
- Unusual facial characteristicsinclude a broad forehead, deep-set and wide-spaced eyes, a saddle nose with a bulbous tip, pointed chin, and large ears.
- Cardiac diseaseoften includes pulmonary outflow obstruction alone or as part of tetralogy of Fallot.
- Renal diseaseoccurs in up to one half of patients.
- Eye anomaliesinclude posterior embryotoxon.
- Musculoskeletal anomaliesinclude butterfly vertebrae and broad thumbs.
- Growth failure and short stature
- Pancreatic insufficiency
- Diagnosisis on the basis of clinical features and, sometimes, liver biopsy and radionucleotide imaging to exclude other causes of cholestasis, such as BA.
- Managementis supportive.
- Wilson's disease
may cause acute and chronic hepatitis and liver failure. Hepatic involvement is more common than neuropsychiatric symptoms during childhood. See Chapter 5, section XI.A.
- Viral Hepatitis
- General concepts
- Epidemiology.Incidence varies with the specific virus. The majority of infections in children and adolescents are caused by hepatitis A and B.
- Liver inflammation associated with viral hepatitis is caused by either hepatotropic viruses (hepatitis A, B, C, D, and E [discussed below]) or other viruses that cause liver inflammation as part of a more widespread disease process (e.g., EBV, varicella-zoster virus, HIV, herpes simplex virus).
- Infection results in varying degrees of liver inflammation and
swelling. Although hepatocytes are primarily infected, hepatobiliary obstruction results from local swelling. Damage also occurs as a result of the host immune response.
- Clinical features. Most infections during infancy and childhood are asymptomatic.
- If present, symptomsmay include malaise, anorexia, vomiting, fever, diffuse or right upper quadrant abdominal pain, edema, and bruising or bleeding.
- Signs on examinationmay include jaundice, hepatosplenomegaly, ascites, increased abdominal vascular markings, caput medusae, spider hemangiomas, and clubbing.
- Managementis supportive in the acute phase with specific therapies for chronic disease.
- Preventionof hepatitis A and B is now possible through vaccination. See Chapter 1, sections III.C.1 and III.C.7 for discussions of these vaccinations.
- Hepatitis A infectionis caused by hepatitis A virus (HAV), a picornavirus.
- Transmissionis by the fecal-oral route through contaminated foods and water or by contact with contaminated individuals (e.g., food handlers). It is the most common hepatitis virus causing infection.
- Virus is shed in the stool 2–3 weeks before the onset of symptoms and 1 week after the onset of jaundice.
- Clinical features
- Incubation periodis 2–6 weeks, with mean symptom onset at 28 days.
- Infection is asymptomatic in the majority of children(> 70%). Jaundice occurs very rarely in symptomatic children. Older children and adults are more likely to have symptomatic infection.
- Chronic infection does not occur, although the disease may relapse with return of symptoms in up to 25%.
- Diagnosis is based on serology.Figure 10-2 describes the time course of infection and the presence of detectable antibodies to HAV.
- Elevated IgM anti-HAVis present early and can persist for as long as 6 months after infection.
- Elevated IgG anti-HAValso occurs early in infection and confers lifelong immunity.
- Managementof symptomatic infection is supportive.
- Hepatitis B infectionis caused by hepatitis B virus (HBV), a DNA virus.
- Epidemiology. Transmissionis by perinatal vertical exposure from an infected mother to her fetus, by the parenteral route through exposure to infected blood products, tattooing needles, and intravenous drug use, or by exposure to infected body secretions.
HBV is found in most body fluids, including blood, tears, saliva, semen, vaginal secretions, urine, feces, and breast milk.
- Clinical features
- Incubation period is 45–160 dayswith mean symptom onset of 90 days.
- Acute symptoms of hepatitis(see section XI E.1.d) occur in < 5% of infants, 5–15% of preschool children, and 30–50% of older children and adolescents. Symptoms are extremely variable, ranging from asymptomatic infection to nonspecific systemic illness to clinical hepatitis and fulminant liver failure.
- Chronic HBV infection is most common in young infantswho acquire the virus from perinatal exposure but is less common in older children. Chronic HBV infection may result in chronic liver disease with cirrhosis, hepatic fibrosis, portal hypertension, and increased risk for hepatocellular carcinoma.
- Diagnosisis on the basis of serology (see also Figure 10-3, which describes the time course of infection and the presence of detectable antigens and antibodies to HBV).
- HBV surface antigen (HBsAg) is pathognomonic for active disease.It is the antigen used in the hepatitis B vaccine.
- HBV surface antibody (HBsAb) is protectiveand can result from vaccination or natural infection.
- HBV core antibody (HBcAb)results from natural infection (not vaccination) and persists lifelong.
- HBV e antigen (HBeAg)rises very early in active infection and is therefore useful in diagnosing acute infection.
- HBV e antibody (HBeAb)rises late in infection.
Figure 10-2. Time course of hepatitis A infection and the presence of detectable antibodies to hepatitis A. IgM Anti-HAV = IgM antibody to hepatitis A; IgG Anti-HAV = IgG antibody to hepatitis A; HAV = hepatitis A virus; ALT = alanine aminotransferase.
- HBV polymerase chain reaction (PCR)may be used for both diagnosis and assessing the response to therapy.
Figure 10-3. Time course of acute hepatitis B infection and the presence of detectable antigens and antibodies to hepatitis B.
- Managementincludes supportive care for acute infection and consideration of interferon-α and antivirals for chronic infection.
- Hepatitis C infectionis caused by hepatitis C virus (HCV), an RNA virus in the flavivirus family.
- Transmissionis by perinatal vertical route from mother to fetus, or by parenteral exposure.
- HCV accounts for 90% of transfusion-associated hepatitis and 50% of “non-A, non-B” hepatitis.
- Clinical features.Acute infection is rarely symptomatic (especially in children), although chronic infection may result in cirrhosis and hepatic fibrosis. Chronic infection occurs in 80% of infected patients.
- Diagnosisis by serology demonstrating HCV antibody in the blood. HCV PCR is used as a confirmatory test for chronic infection.
- Hepatitis D infectionis caused by hepatitis delta virus (HDV), an RNA virus that requires HBsAg for replication. Transmission is by parenteral exposure and infection can occur with or without active hepatitis B infection. Infection may be inconsequential, may cause progression of hepatitis
B infection, or may precipitate fulminant liver failure. Diagnosis is by serology demonstrating HDV antigen and antibody.
- Hepatitis E infectionis caused by hepatitis E virus (HEV), an RNA virus. Hepatitis E is responsible for 50% of acute hepatitis in young adults in developing countries and is associated with 20% mortality in infected pregnant women. Transmission is by fecal-oral route. Chronic disease does not occur. Diagnosis is by serology demonstrating HEV antibodies.
- Autoimmune Hepatitis
- Definition.This destructive and progressive liver disease is characterized by elevated serum transaminases, hypergammaglobulinemia, and circulating autoantibodies.
- Categories.Two categories of autoimmune hepatitis are based on autoantibody types.
- Type 1 diseaseis characterized by the presence of antinuclear antibody (ANA) or anti-smooth muscle antibody. Type 1 disease is more common than type 2 disease.
- Type 2 diseaseis characterized by anti-liver kidney microsome antibody or anti-liver cytosol type 1 antibody.
- Autoimmune hepatitis occurs predominantly in females with presentation before puberty.
- Other nonhepatic autoimmune diseases(e.g., UC, vasculitis, vitiligo) occur in 20–40% of patients.
- Clinical features
- Fifty percentof patients present with acute hepatitis, mimicking viral hepatitis, and 50% of patients present with chronic liver disease.
- Jaundiceis usually mild to moderate.
- Nonhepatic signs and symptomsinclude fatigue, anorexia, arthritis, rash, nephritis, and vasculitis.
- Diagnosisis on the basis of clinical presentation, typical laboratory findings, and exclusion of other liver diseases. A high degree of suspicion is required in patients with a family history of autoimmune disease, in those with nonhepatic autoimmune disease, and in those with chronic liver disease.
- Laboratory studiesreveal elevated serum transaminases, hypergammaglobulinemia, and circulating autoantibodies.
- Liver biopsyis generally performed to evaluate for cirrhosis, to grade disease activity, and to exclude other diagnoses.
- Managementincludes supportive care, corticosteroids for initial control of hepatic inflammation, and immunosuppressive agents, such as azathioprine or 6-mercaptopurine. Liver transplantation is indicated for severe liver disease.
Review Questions and Answers
- A 2-month-old infant presents with acute onset of crying and bilious vomiting. On examination, her abdomen is tender and distended. Upper intestinal contrast imaging demonstrates intestinal malrotation with midgut volvulus. Which of the following conditions is also associated with malrotation?
(A). Hypertrophic pyloric stenosis
(B). Ulcerative colitis
(C). Renal anomalies
(D). Down syndrome
- A 6-week-old male infant is admitted to the pediatric ward with vomiting and dehydration. The parents note that their child has been vomiting for the past 3 weeks with increasing severity and frequency. Initially, he would spit up a small amount after every other feeding. However, for the past week, he has vomited forcefully after each breastfeeding. To the parents, it seems like he vomits the entire feeding. He has remained hungry, is afebrile, and has no diarrhea. During the past 2 days, he has had only two wet diapers per day. After admission, serum electrolytes are drawn. Based on the most likely diagnosis, which of the following would be the most likely electrolyte pattern?
(A). Hypernatremic, hypokalemic metabolic acidosis
(B). Hypernatremic, hypokalemic metabolic alkalosis
(C). Hypochloremic, hypokalemic metabolic alkalosis
(D). Hyperchloremic, hypokalemic metabolic alkalosis
(E). Hypochloremic, hypokalemic, metabolic acidosis
- You are called to evaluate a newborn in the nursery who has been vomiting after every feeding. The prenatal history is notable for polyhydramnios, and the physical examination is significant for a scaphoid abdomen and paucity of bowel sounds. Which of the following is the most likely diagnosis?
(A). Congenital diaphragmatic hernia
(B). Hypertrophic pyloric stenosis
(C). Intestinal malrotation
(D). Duodenal atresia
(E). Hirschsprung's disease
- An 8-year-old girl is brought to the emergency department with a 3-day history of periumbilical abdominal pain that radiates to the back, as well as nausea, vomiting, and anorexia. The girl's mother denies any recent travel, ill contacts, and trauma to her abdomen. Laboratory assessment reveals an elevated white blood cell count, mild hyperglycemia, and elevated amylase and lipase. The clinical picture appears consistent with pancreatitis. Which of the following is the most likely underlying cause of her disorder?
(C). Viral infection
(D). Drug or toxin exposure
(E). Congenital anomalies of the pancreas
- A previously healthy 9-month-old girl is brought to the emergency department with an 18-hour history of intermittent, inconsolable crying interspersed with periods of lethargy. She has vomited twice and has had one bowel movement that the mother describes as bloody. Based on the clinical presentation, which of the following is the most appropriate diagnostic procedure at this time?
(A). Plain abdominal radiography
(B). Upper gastrointestinal imaging with small bowel follow through study
(C). Barium enema
(D). Surgical exploration
(E). Abdominal ultrasound
- A 3-year-old boy is brought to the office by his parents, who are concerned because he has hard, painful stools. For the past 4 months, their son defecates every 3–4 days and cries during the stooling. The resulting stool is very hard. Physical examination of the child is normal. Which of the following is correct regarding his constipation?
(A). His constipation is unlikely to lead to encopresis.
(B). A barium enema should be ordered to evaluate for Hirschsprung's disease.
(C). His constipation likely resulted from a traumatic triggering event, such as a severe, painful diaper rash or painful diarrhea.
(D). Abdominal radiographs should be ordered to evaluate for an underlying organic cause of his constipation.
(E). The parents should be instructed to encourage their son to drink juice with each meal, and the boy should be reevaluated in 3–4 months.
- A 4-week-old, formula-fed male infant has a history of blood-tinged stools with mucus for the past few days. His mother reports that he has been fussier than usual lately but has had no fever, vomiting, or cold symptoms. Physical examination reveals mild abdominal distension but is otherwise normal. You suspect cow's milk protein allergy. Which of the following is the most appropriate next step to confirm diagnosis?
(A). Abdominal radiographs
(B). Small bowel biopsy
(C). Allergen skin testing
(D). Stool-reducing substances and pH
(E). Change his diet to an alternative protein source
The response options for statements 8 and 9 are the same. You will be required to select one answer for each statement in the set.
For each patient, select the likely diagnosis.
- A 15-year-old girl presents with abdominal cramps and diarrhea for 2 weeks. Examination reveals two perianal skin tags and pubertal delay.
(A). Celiac disease
(B). Crohn's disease
(C). Ulcerative colitis
(D). Irritable bowel syndrome
(E). Lactase deficiency
- A 10-year-old boy presents with bloody diarrhea and abdominal pain. Serologic studies reveal the presence of anti-neutrophil cytoplasmic antibody.
(A). Celiac disease
(B). Crohn's disease
(C). Ulcerative colitis
(D). Irritable bowel syndrome
(E). Lactase deficiency
- A 4-year-old girl is brought to the urgent care center with an acute onset of vomiting blood. Her parents report that her symptoms began abruptly 3 hours ago, and since then she has had four episodes of bloody emesis. Vital signs reveal a heart rate of 152 beats/min and a blood pressure of 110/56 mm Hg. Which of the following is the most appropriate first step in management?
(A). Begin intravenous H2-blockers.
(B). Order urgent upper endoscopy.
(C). Order a complete blood count to assess the patient's hemoglobin.
(D). Place two large-bore peripheral lines and administer a 20 mL/kg normal saline fluid bolus.
(E). Place a nasogastric tube and aspirate to assess for blood.
- A 12-month-old female infant with failure to thrive is brought to the office. Her parents note that she is very fussy and often spits up after feedings. She also has two loose foul-smelling stools each day. Serologic testing reveals elevated serum tissue transglutaminase antibody. Which of the following foods can she eat safely without aggravating or inducing her symptoms?
- A 4-month-old female infant has gastroesophageal reflux disease confirmed by pH probe. She has failed to respond to conservative management that included positioning and thickened feeds. Which of the following is the most appropriate next management step?
(A). Initiation of medical therapy
(B). Changing her diet to a hydrolyzed amino acid formula
(C). Nissen fundoplication
(D). Gastric antroplasty
(E). Gastrostomy tube feedings
- A 5-week-old male infant has been brought to the clinic by his parents, who have concerns about jaundice. He was born at full-term, weighing 8 pounds, 9 ounces, and he had an uncomplicated delivery and neonatal course. Today, his weight is 9 pounds, 1 ounce, and his vital signs are normal. On examination, his liver is enlarged and 4 cm below the right costal margin. Jaundice is present. Laboratory evaluation reveals a total bilirubin of 12.9 mg/dL with a direct component of 5.9 mg/dL. Which of the following is the next most appropriate step in management?
(A). Begin phototherapy to treat the patient's jaundice.
(B). Refer the patient for a liver transplant.
(C). Begin ursodeoxycholic acid to enhance bile flow.
(D). Order an urgent abdominal ultrasound and radionucleotide imaging study of the liver.
(E). Reassure the parents that no treatment is required as he likely has neonatal hepatitis.
- A 5-year-old girl has a 4-day history of nausea, vomiting, diarrhea, and loss of appetite. On physical examination, her conjunctiva are icteric, and the right upper quadrant of her abdomen is tender. You suspect hepatitis A infection. Which of the following is correct regarding this diagnosis?
(A). The presence of jaundice is unusual in a child of her age with hepatitis A infection.
(B). She should also be tested for hepatitis D infection, which may occur in association with hepatitis A.
(C). Chronic infection occurs in 25% of patients.
(D). She is likely to be noninfectious at this point in her illness.
(E). Serologic testing at this point in her illness will reveal elevated IgM antibody to hepatitis A only; IgG antibody to hepatitis A rises late in infection.
- A 10-year-old girl is in the office for follow-up of abdominal pain that first occurred 5 months ago. The pain is periumbilical in location and is described vaguely as sometimes sharp, sometimes dull, and sometimes burning. The pain occurs only during the day; she denies waking up at night secondary to pain. She is able to participate in her soccer practice and games after school and on weekends. Fever, vomiting, diarrhea, and dysuria are all absent. Examination is normal, except for very mild abdominal tenderness on palpation of her periumbilical region. She is otherwise a very healthy-appearing girl with normal growth and development. You suspect functional abdominal pain. Which of the following is correct regarding this diagnosis?
(A). Almost all patients have resolution of their symptoms by adulthood.
(B). Most cases of chronic abdominal pain have an organic cause.
(C). Your counseling should include making sure the patient understands that her pain is not real, but imagined.
(D). Even though her pain is functional, she may also have a minor disturbance in her sympathetic or parasympathetic nervous system that has put her at risk for pain.
(E). Given the degree of pain, she should be given permission to miss school when the pain is present.
Answers and Explanations
- The answer is E[IV.B.2]. Malrotation is the result of abnormal rotation and fixation of the intestines in utero. In heterotaxy, the intestines begin their rotation from an already abnormal position and this results in final fixation in a variable position. This variable rotation and final position can lead to twisting of the intestines and volvulus. Pyloric stenosis is a thickening of the pylorus muscle that results in projectile vomiting. Intestinal malrotation is not present in this disorder. Ulcerative colitis is a type of inflammatory bowel disease in which many intestinal manifestations may be present, including rectal bleeding, diarrhea, abdominal pain, and toxic megacolon, but not intestinal malrotation. Patients with Down syndrome may have duodenal atresia but are at no increased risk for malrotation. Renal anomalies are not associated with malrotation.
- The answer is C[IV.A.4, IV.A.5]. The infant's symptoms are the classic presentation of hypertrophic pyloric stenosis. Forceful vomiting of stomach contents develops, and the vomiting persists unless it is corrected surgically. This persistent vomiting causes a progressive loss of hydrogen ions and chloride, resulting in hypochloremia and a metabolic alkalosis. If hydrogen ion loss is severe, hypokalemia often develops as well.
- The answer is D[IV.C.1]. Duodenal atresia is a congenital anomaly that develops because of failure of the intestinal lumen to recanalize early in gestation. As a result, the fetus is unable to swallow significant amounts of amniotic fluid, and this may lead to polyhydramnios. Postnatally, duodenal atresia leads to vomiting, epigastric distension (proximal to the obstruction), and an absence of intestinal bowel gas that causes a scaphoid appearance to the abdomen. Although the abdomen may be scaphoid in appearance with congenital diaphragmatic hernia, polyhydramnios is not associated with this condition, and these infants present with severe respiratory distress at birth. Neither pyloric stenosis, malrotation, nor Hirschsprung's disease is associated with a scaphoid abdomen or polyhydramnios.
- The answer is A[V.B.2.d]. In children, approximately 25% of cases of pancreatitis are idiopathic (without identifiable cause). Idiopathic pancreatitis is second only to blunt abdominal trauma, which is the leading cause of acute pancreatitis during childhood. Sepsis, viral infections, and drug or toxin exposure are other important causes of pancreatitis in children but are less common than trauma or the idiopathic category. Congenital anomalies of the pancreas and biliary tree are also less common causes.
- The answer is C[IV.D.5]. This infant's history is consistent with intussusception, in which the intestine telescopes into itself, causing bowel wall edema, mucosal injury, and eventually necrosis. The child typically presents with colicky abdominal pain, often accompanied by vomiting, lethargy, and bloody stools. The most important diagnostic test is the contrast enema, which demonstrates the involved intestinal segment. In addition, the pressure from the contrast enema will usually reduce the intussusception. The contrast enema is therefore both diagnostic and therapeutic. Although ultrasound may demonstrate the intussusception, it is generally not the initial diagnostic study for a patient with presumed intussusception. Surgical exploration is indicated for intussusception that fails to reduce with contrast enema or if peritonitis is suspected. Plain radiography is not generally sensitive for diagnosis. Upper gastrointestinal imaging with small bowel follow through will not show most cases of intussusception, which most commonly occurs in the ileocolic location.
- The answer is C[VII.D.1]. This patient's constipation is most likely functional or nonorganic (functional fecal retention). Functional constipation results from an inappropriate constriction of the external anal sphincter. Most commonly, toddlers retain stool purposely because of a traumatic event, such as a painful diaper rash, painful diarrhea, or even physical or sexual abuse. Encopresis is almost always associated with severe constipation and could eventually result in this patient. Organic causes of constipation (e.g., Hirschsprung's disease, hypothyroidism, infant botulism) account for less than 5% of constipation seen during childhood. Therefore, radiographic studies are not indicated unless suggested on the basis of history or physical examination. Because this patient's constipation is associated with pain, management should include stool evacuation using mineral oil, enemas, or other modalities. Recommendations for increased dietary fiber, water, and juice are important adjuncts to treatment but alone are insufficient for this patient whose constipation is significant and resulting in very hard stools and crying during defecation.
- The answer is E[II.B.4]. Protein intolerance occurs in up to 8% of all infants and is usually caused by cow's milk protein or soy protein allergy. Protein intolerance may present with vomiting, diarrhea, irritability, rectal bleeding, and weight loss. Diagnosis of protein intolerance is made on resolution of symptoms after a complete withdrawal of the suspected antigen. Symptoms usually resolve within 1–2 weeks of stopping the offending protein. Because this approach to treatment and diagnosis is noninvasive and effective, abdominal radiographs, small bowel biopsy, and allergy testing are not necessary and are overly invasive for this 4-week-old. In addition, radiographs are not diagnostic, and this infant is too young for a response to allergy skin testing. Stool-reducing substances and an abnormal acidic pH are found in carbohydrate, not protein, malabsorption.
8 and 9. The answers are B and C, respectively [IX.C and Table 10-4]. Patients with Crohn's disease, like the girl in question 8, may present with diarrhea, abdominal cramping, and loss of appetite. Perianal skin disease, such as skin tags, fissures, and fistulas, may precede intestinal symptoms. Patients with Crohn's disease may also have poor growth and delayed puberty. Patients with ulcerative colitis, like the boy in question 9, often present with rectal bleeding, diarrhea, and abdominal pain. Eighty percent are positive for antineutrophil cytoplasmic antibody. In contrast, celiac disease presents with bloating, foul-smelling stools, diarrhea, and vomiting. Delayed sexual maturity is unusual, stools are nonbloody, and perianal disease is not usually present. Irritable bowel syndrome is associated with bloating, cramping, and alterations in stool patterns. Lactase deficiency is a disorder of carbohydrate absorption and presents with bloating and diarrhea.
- The answer is D[X.C.3.a]. Before further investigation or definitive therapy, the most important step in any patient who may have hypovolemia or significant or worsening anemia is initial stabilization, including the ABCs (airway, breathing, and circulation). This includes placement of two large-bore intravenous lines for fluid resuscitation. Because the heart rate is elevated, suggesting hypovolemia, a normal saline solution bolus would also be an appropriate initial step in management. After stabilization, placement of a nasogastric tube to confirm upper gastrointestinal bleeding and ordering a complete blood count to assess the patient's hemoglobin are appropriate. Intravenous H2-blockers are used if gastritis, esophagitis, or ulcer disease is suspected. Upper endoscopy would also likely be needed to diagnose the cause of the bleeding, but after the patient has been initially stabilized.
- The answer is A[II.C.2.b, II.C.5]. This patient presents with the classic features of celiac disease (gluten-sensitive enteropathy). Signs and symptoms usually develop between 6 months and 2 years of age when gluten is introduced into the diet. The treatment of celiac disease is restriction of gluten from the diet. Wheat, barley, and rye all contain gluten. Oats also usually contain gluten because most oats are harvested in fields that also contain wheat. Rice is the only food listed that does not contain gluten and can be eaten safely by patients with celiac disease.
- The answer is A[III.G.2]. Gastroesophageal reflux disease results from inappropriate transient lower esophageal sphincter relaxation that allows gastric contents to reflux into the esophagus, and manifests as vomiting, irritability, arching of the back, poor weight gain, and pulmonary symptoms (e.g., wheezing). After a trial of conservative management that includes positioning and thickened feeds, medical management with antacids, H2-blockers, proton pump inhibitors, or motility agents is indicated. Dietary changes would be ineffective at this time. Nissen fundoplication with gastric antroplasty and gastrostomy tube feedings may be required should medical management fail.
- The answer is D[XI.C.1, XI.C.4.e, XI.C.4.f]. This patient has cholestasis, or retention of bile within the liver, manifested by the elevated conjugated (direct) bilirubin. In addition, the findings of hepatomegaly and poor growth (he has only gained 8 ounces since birth) support the diagnosis of cholestasis. The causes of cholestasis are many, and biliary atresia and choledochal cyst must always be considered and rapidly ruled out in any infant who presents with conjugated hyperbilirubinemia. This evaluation includes an abdominal ultrasound, radionucleotide imaging, and liver biopsy in rapid sequence. Should biliary atresia not be identified promptly (by 50–70 days of age), liver transplantation may be the only treatment option. Phototherapy is not indicated for direct hyperbilirubinemia. Neonatal hepatitis is a possible cause of this patient's symptoms, but biliary atresia must first be ruled out. Ursodeoxycholic acid enhances bile flow, but it is recommended only once biliary obstruction has been excluded.
- The answer is A[XI.F.2 and Figure 10-2]. Hepatitis A infection is the most common hepatitis virus infection and usually occurs through fecal-oral contamination. Only 30% of children infected with the hepatitis A virus have symptoms of hepatitis (the majority of hepatitis A infections are asymptomatic during childhood), but even those with hepatitis symptoms very rarely have jaundice. Hepatitis D infection requires the presence of hepatitis B surface antigen (HBsAg) for replication, not hepatitis A virus. Chronic hepatitis A infection does not occur, but up to 25% can have a relapse of symptoms at some point after recovery from the initial infection. Patients shed virus in the stool for 2–3 weeks before the onset of any symptoms and for 1 week after the onset of symptoms. Serologic testing confirms the diagnosis. Both IgM and IgG antibodies to hepatitis A virus rise early in infection.
- The answer is D[VI.C.2]. Nonorganic or functional abdominal pain is much more common than organic abdominal pain in children. Yet, although the pain is nonorganic, some children do have minor disturbances in gastrointestinal motility or in their parasympathetic or sympathetic nervous systems that make them susceptible to the pain. It is important to understand that the pain is real to the patient, and therefore management should focus on empowering the child and family to overcome the discomfort. In addition, the child must resume and normalize all activities, including attending school even when pain is present. Although 50% of patients have resolution of symptoms during childhood, at least 25% still have pain as adults.