Principles of surgery

PART II
Specific Considerations

CHAPTER 39
Pediatric Surgery

BASIC SCIENCE QUESTIONS

1. Total body water in a full-term infant is approximately

A. 60 mL/kg

B. 80 mL/kg

C. 100 mL/kg

D. 120 mL/kg

Answer: B

At 12 weeks’ gestation, the total body water of a fetus is approximately 94 mL/kg. By the time the fetus reaches full term, the total body water has decreased to approximately 80 mL/kg. Total body water drops an additional 5% within the first week of life, and by 1 year of life, total body water approaches adult levels, 60 to 65 mL/kg. (See Schwartz 9th ed., p 1412.)

2. Approximately how many calories per day are required to support growth in a newborn infant?

A. 110 kcal/kg/day

B. 90 kcal/kg/day

C. 70 kcal/kg/day

D. 55 kcal/kg/day

Answer: A

The protein and caloric requirements for the surgical neonate are shown in Table 39-1. (See Schwartz 9th ed., p 1413.)

TABLE 39-1 Nutritional requirements for the pediatric surgical patient

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3. Mutation in which of the following genes has been associated with Hirschsprung’s disease?

A. Glial cell line-derived neurotrophic factor (GDNF)

B. “Rearranged during transfection” (RET)

C. GDNF family receptor alphañ1 (Gfra-1)

D. All of the above

Answer: D

Recent studies have shed light on the molecular basis for Hirschsprung’s disease. Patients with Hirschsprung’s disease have an increased frequency of mutations in several genes, including GDNF, its receptor Ret, and its coreceptor Gfra-1. Moreover, mutations in these genes also lead to aganglionic megacolon in mice, which provides the opportunity to study the function of the encoded proteins. Initial investigations indicate that GDNF promotes the survival, proliferation, and migration of mixed populations of neural crest cells in culture. Other studies have revealed that GDNF is expressed in the gut in advance of migrating neural crest cells and is chemoattractive for neural crest cells in culture. These findings raise the possibility that mutations in the GDNF or Ret genes could lead to impaired neural crest migration in utero and the development of Hirschsprung’s disease. (See Schwartz 9th ed., p 1436.)

4. The glomerular filtration rate of a newborn is approximately

A. 30% less than a normal adult

B. 60% less than a normal adult

C. 30% more than a normal adult

D. 60% more than a normal adult

Answer: B

Precise management of a neonate’s fluid status requires an understanding of changes in the glomerular filtration rate (GFR) and tubular function of the kidney. The full-term newborn’s GFR is approximately 21 mL/min per square meter compared with 70 mL/min per square meter in an adult. Within the first year GFR increases steadily to the point that it essentially reaches adult levels by the end of the first year of life. The capacity to concentrate urine is very limited in preterm and term infants. In comparison with an adult who can concentrate urine to 1200 mOsm/kg, infants can concentrate urine at best to 600 mOsm/kg. Although infants are capable of secreting antidiuretic hormone, the aquaporin water channelñmediated osmotic water permeability of the infant’s collecting tubules is severely limited compared with that of an adult, which leads to insensitivity to antidiuretic hormone. (See Schwartz 9th ed., p 1412.)

5. Third branchial cleft anomalies are located

A. Anterior to the carotid artery

B. Posterior to the carotid artery

C. Lateral to the carotid artery

D. Between the branches of the external and internal carotid arteries

Answer: B

Paired branchial clefts and arches develop early in the fourth gestational week. The first cleft and the first, second, third, and fourth pouches give rise to adult organs. The embryologic communication between the pharynx and the external surface may persist as a fistula. A fistula is seen most commonly with the second branchial cleft, which normally disappears, and extends from the anterior border of the sternocleidomastoid muscle superiorly, passes inward through the bifurcation of the carotid artery, and enters the posterolateral pharynx just below the tonsillar fossa. In contrast, a third branchial cleft fistula passes posterior to the carotid bifurcation. (See Schwartz 9th ed., p 1414.)

6. The blood volume of a 3-kg newborn infant is approximately

A. 150 mL

B. 240 mL

C. 300 mL

D. 450 mL

Answer: B

A useful guideline for estimating blood volume for the newborn infant is approximately 80 mL/kg of body weight. (See Schwartz 9th ed., p 1412.)

7. Approximately how many calories are in 1 ounce (30 mL) of breast milk?

A. 20 kcal

B. 30 kcal

C. 42 kcal

D. 50 kcal

Answer: A

There are approximately 0.67 kcal/cc in one mL of breast milk. Therefore, there are about 20 kcals in 1 ounce (30 mL) of breast milk. (See Schwartz 9th ed., p 1413, and Table 39-2.)

TABLE 39-2 Formulas for pediatric surgical neonates

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CLINICAL QUESTIONS

1. Thyroglossal ducts are usually diagnosed at

A. Birth

B. 6-9 months of age

C. 2-4 years of age

D. 5-8 years of age

Answer: C

Thyroglossal duct cysts are most commonly appreciated in the 2- to 4-year-old child when the baby fat disappears and irregularities in the neck become more readily apparent. Usually the cyst is encountered in the midline at or below the level of the hyoid bone and moves up and down with swallowing or with protrusion of the tongue. Occasionally it presents as an intrathyroidal mass. Most thyroglossal duct cysts are asymptomatic. (See Schwartz 9th ed., p 1414.)

2. Malignant tumors are uncommon in children with sacrococcygeal teratomas. When they are present, however, the most common tumor is

A. Rhabdomyosarcoma

B. Neuroblastoma

C. Yolk sac tumor

D. Malignant teratoma

Answer D

Sacrococcygeal teratoma usually presents as a large mass extending from the sacrum in the newborn period. Diagnosis may be established by prenatal ultrasonography. In fetuses with evidence of hydrops and a large sacrococcygeal teratoma, prognosis is poor; thus prenatal intervention has been advocated in such patients. The mass may be as small as a few centimeters in diameter or as massive as the size of the infant (Fig. 39-1). The tumor has been classified based on the location and degree of intrapelvic extension. Lesions that grow predominantly into the presacral space often present later in childhood. The differential diagnosis consists of neural tumors, lipoma, and myelomeningoceles. Most tumors are identified at birth and are benign. Malignant yolk sac tumor histology occurs in a minority of these tumors. (See Schwartz 9th ed., p 1451.)

FIG. 39-1. Sacrococcygeal teratoma in a 2-day-old boy.

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3. In children, hernias are most common

A. In boys, on the left side

B. In boys, on the right side

C. In girls, on the left side

D. In girls, on the right side

Answer: B

Inguinal hernias occur more commonly in males than in females (10:1) and are more common on the right side than the left. (See Schwartz 9th ed., p 1444.)

4. The mortality rate for congenital diaphragmatic hernia is approximately

A. 15%

B. 35%

C. 50%

D. 70%

Answer: C

The vast majority of infants with CDH develop immediate respiratory distress, which is due to the combined effects of three factors. First, the air-filled bowel in the chest compresses the mobile mediastinum, which shifts to the opposite side of the chest, so that air exchange in the contralateral lung is compromised. Second, pulmonary hypertension develops. This phenomenon results in persistent fetal circulation, with resultant decreased pulmonary perfusion, and impaired gas exchange. Finally, the lung on the affected side is often markedly hypoplastic, so that it is essentially nonfunctional. Varying degrees of pulmonary hypoplasia on the opposite side may compound these effects. As a result, neonates with CDH are extremely sick, and the overall mortality in most series is approximately 50%. (See Schwartz 9th ed., p 1416.)

5. A 5-week-old infant presents to the emergency room with bilious vomiting, lethargy, and poor urine output. Following resuscitation, based on the film in Fig. 39-2, the next intervention should be

A. NG decompression and observation

B. Upper GI series

C. Contrast enema

D. Laparotomy

Answer: D

Midgut volvulus can occur at any age, although it is seen most often in the first few weeks of life. Bilious vomiting is usually the first sign of volvulus, and all infants with bilious vomiting must be evaluated rapidly to ensure that they do not have intestinal malrotation with volvulus. This diagnosis should be suspected in a child with irritability and bilious emesis. If the condition is left untreated, vascular compromise of the midgut initially causes bloody stools but eventually results in circulatory collapse. Additional clues to the presence of advanced ischemia of the intestine include erythema and edema of the abdominal wall, which progresses to shock and death. It must be re-emphasized that the index of suspicion for this condition must be high, because abdominal signs are minimal in the early stages. Abdominal films show a paucity of gas throughout the intestine with a few scattered air-fluid levels (Fig. 39-2). When these findings are present, the patient should undergo immediate fluid resuscitation to ensure adequate perfusion and urine output, followed by prompt exploratory laparotomy. (See Schwartz 9th ed., p 1428.)

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FIG. 39-2

6. Which of the following is NOT part of the VACTERL complex?

A. Vertebral anomalies

B. Imperforate anus

C. Congenital diaphragmatic hernia

D. Renal anomalies

Answer: C

VACTERL syndrome is associated with vertebral anomalies (absent vertebrae or hemivertebrae), anorectal anomalies (imperforate anus), cardiac defects, tracheoesophageal fistula, renal anomalies (renal agenesis, renal anomalies), and radial limb anomalies (most often radial dysplasia). (See Schwartz 9th ed., p 1421.)

7. Intestinal duplications are most commonly located in the

A. Duodenum

B. Jejunum

C. Ileum

D. Colon

Answer: C

Intestinal duplications are mucosa-lined structures that are in continuity with the GI tract. Although they can occur at any level in the GI tract, duplications are found most commonly in the ileum within the leaves of the mesentery. Duplications may be long and tubular, but usually are cystic masses. In all cases, they share a common wall with the intestine. Symptoms associated with enteric duplication cysts include recurrent abdominal pain, emesis from intestinal obstruction, and hematochezia. Such bleeding typically results from ulceration in the duplication or in the adjacent intestine if the duplication contains ectopic gastric mucosa. (See Schwartz 9th ed., p 1435.)

8. A 2-week-old with mild respiratory distress is seen in the emergency room. Based on the chest radiograph obtained (see Fig. 39-3), the most likely diagnosis is

A. Respiratory syncticial virus infection

B. Spontaneous pneumothorax

C. Congenital lobar emphysema

D. Congenital pulmonary airway malformation

Answer: C

Congenital lobar emphysema (CLE) is a condition manifested during the first few months of life as a progressive hyperexpansion of one or more lobes of the lung. It can be life-threatening in the newborn period, but in the older infant it causes less respiratory distress. Air entering during inspiration is trapped in the lobe. On expiration, the lobe cannot deflate and progressively overexpands, which causes atelectasis of the adjacent lobe or lobes. This hyperexpansion eventually shifts the mediastinum to the opposite side and compromises the other lung. CLE usually occurs in the upper lobes of the lung (left more often than right), followed next in frequency by the right middle lobe; however, it can occur in the lower lobes as well. It is caused by intrinsic bronchial obstruction from poor bronchial cartilage development or extrinsic compression.

Congenital pulmonary airway malformation (CPAM) consists of cystic proliferation of the terminal airway, which produces cysts lined by mucus-producing respiratory epithelium and elastic tissue in the cyst walls without cartilage formation. There may be a single cyst with a wall of connective tissue containing smooth muscle. Formerly known as congenital cystic adenomatoid malformation, CPAM may consist of a single large cyst or multiple cysts (type I), may be characterized by smaller and more numerous cysts (type II), or may resemble fetal lung without macroscopic cysts (type III). CPAMs frequently occur in the left lower lobe. However, this lesion can occur in any lobe or may occur in both lungs simultaneously. (See Schwartz 9th ed., p 1418.)

Spontaneous pneumothorax is rare in infants. Loculated airtrapping, like that seen on the chest radiograph in Fig. 39-3, is not usually seen with RSV infection.

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FIG. 39-3

9. The defect in gastroschisis is usually

A. In the midline, superior to the umbilicus

B. In the midline, inferior to the umbilicus

C. To the right of the umbilicus

D. To the left of the umbilicus

Answer: C

Gastroschisis is a congenital anomaly characterized by a defect in the anterior abdominal wall through which the intestinal contents freely protrude. Unlike with omphalocele, there is no overlying sac and the size of the defect is much smaller (4 cm). The abdominal wall defect is located at the junction of the umbilicus and normal skin and is almost always to the right of the umbilicus. (See Schwartz 9thed., p 1443.)

10. The most common type of choledochal cyst is

A. Type I

B. Type II

C. Type III

D. Type IV

Answer: A

Based on the classification system proposed by Alonso-Lej, five types of choledochal cyst are described. Type I cysts are characterized by fusiform dilatation of the bile duct. This type is the most common and is found in 80 to 90% of cases. Type II choledochal cysts appear as an isolated diverticulum protruding from the wall of the common bile duct. The cyst may be joined to the common bile duct by a narrow stalk. Type III choledochal cysts arise from the intraduodenal portion of the common bile duct and are also known as choledochoceles. Type IVA cysts consist of multiple dilatations of the intrahepatic and extrahepatic bile ducts. Type IVB choledochal cysts are multiple dilatations involving only the extrahepatic bile ducts. Type V cysts (Caroli’s disease) consist of multiple dilatations limited to the intrahepatic bile ducts. (See Schwartz 9th ed., p 1440.)

11. A premature infant with bloody stools, bilious emesis, and the following KUB (see Fig. 39-4) should be treated with

A. NG decompression and antibiotics

B. Percutaneous abdominal drainage with peritoneal irrigation

C. Exploratory laparotomy, resection of the involved bowel, and primary anastomosis

D. Exploratory laparotomy, resection of the involved bowel, and end ostomies

Answer: A

In all infants suspected of having NEC, feedings are discontinued, a nasogastric tube is placed, and broad-spectrum parenteral antibiotics are given. The infant is resuscitated, and inotropes are administered to maintain perfusion as needed. Intubation and mechanical ventilation may be required to maintain oxygenation. TPN is started. Subsequent treatment may be influenced by the particular stage of NEC that is present. Patients with Bell stage I disease are closely monitored and generally remain on nil per os (NPO) status and are given IV antibiotics for 7 to 10 days before enteral nutrition is resumed. After this time, provided the infant fully recovers, feedings may be reinitiated. Patients with Bell II disease merit close observation. Serial physical examinations are performed to look for the development of diffuse peritonitis, a fixed mass, progressive abdominal wall cellulitis, or systemic sepsis. If the infant fails to improve after several days of treatment, consideration should be given to exploratory laparotomy. (See Schwartz 9th ed., p 1432.)

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FIG. 39-4

12. The most common type of tracheoesophageal anomaly is

A. Pure esophageal atresia (without fistula)

B. Esophageal atresia with distal fistula

C. Esophageal atresia with proximal fistula

D. Tracheoesophageal fistula (without atresia)

Answer: B

The five major varieties of EA and TEF are shown in Fig. 39-5. The most commonly seen variety is EA with distal TEF (type C), which occurs in approximately 85% of the cases in most series. The next most frequent is pure EA (type A), occurring in 8 to 10% of patients, followed by TEF without EA (type E). The latter occurs in 8% of cases and is also referred to as an H-type fistula, based on the anatomic similarity to that letter. EA with fistula between both the proximal and distal ends of the esophagus and trachea (type D) is seen in approximately 2% of cases, and type B, EA with TEF between the proximal esophagus and trachea, is seen in approximately 1% of cases. (See Schwartz 9th ed., p 1421, and Fig. 39-5.)

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FIG. 39-5. The five varieties of esophageal atresia (EA) and tracheoesophageal fistula (TEF). A. Isolated EA. B. EA with TEF between the proximal segment of the esophagus and the trachea. C. EA with TEF between the distal esophagus and the trachea D. EA with fistula between both the proximal and distal ends of the esophagus and the trachea. E. TEF without EA (H-type fistula).

13. The expected survival for a patient with Stage IV Wilms’ tumor is approximately

A. 5%

B. 33%

C. 50%

D. 80%

Answer: D

Wilms’ tumor is the most common primary malignant tumor of the kidney in children. Approximately 500 new cases are seen annually in the United States, and most are diagnosed in children between 1 and 5 years of age with the peak incidence at age 3. Advances in the care of patients with Wilms’ tumor have resulted in an overall cure rate of roughly 90%, even in the presence of metastatic spread.

Essentially, patients who have disease confined to one kidney that is completely excised surgically receive a short course of chemotherapy, and for this group a 97% 4-year survival is expected, with tumor relapse rare after that time. Patients who have more advanced disease or tumors with unfavorable histologic features receive more intensive chemotherapy and radiation therapy. Even in patients with stage IV disease, cure rates of 80% are achieved. (See Schwartz 9th ed., p 1449.)

14. The most common cause of serious head injury in toddlers is

A. Motor vehicle accidents

B. Fall from a height

C. Autopedestrian accident

D. Nonaccidental trauma

Answer: D

The central nervous system (CNS) is the most commonly injured system, and CNS trauma is the leading cause of death among injured children. In the toddler age group, nonaccidental trauma is the most common cause of serious head injury. Findings suggestive of abuse include the presence of retinal hemorrhage on funduscopic evaluation and intracranial hemorrhage without evidence of external trauma (indicative of a shaking injury) as well as fractures at different stages of healing on skeletal survey. (See Schwartz 9th ed., p 1452.)

15. Which of the following procedures is the procedure of choice to correct biliary atresia?

A. Choledochojejunostomy

B. Cholecystojejunostomy

C. Hepatoportoenterostomy

D. None of the above

Answer: C

Currently, first-line therapy for the treatment of biliary atresia consists of creation of a hepatoportoenterostomy, as described by Kasai. The purpose of this procedure is to promote bile flow into the intestine. The procedure is based on Kasai’s observation that the fibrous tissue at the porta hepatis invests microscopically patent biliary ductules that, in turn, communicate with the intrahepatic ductal system. Transecting this fibrous tissue at the portal plate, which is invariably encountered cephalad to the bifurcating portal vein, opens these channels and establishes bile flow into a surgically constructed intestinal conduit, usually a Roux-en-Y limb of jejunum (Fig. 39-6). (See Schwartz 9th ed., p 1439.)

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FIG. 39-6. Schematic illustration of the Kasai portoenterostomy for biliary atresia. An isolated limb of jejunum is brought to the porta hepatis and anastomosed to the transected ducts at the liver plate.

16. The diagnosis of Hirschsprung’s is made by

A. The clinical finding of inability to pass meconium

B. The presence of a transition zone on contrast enema

C. Genetic analysis

D. Rectal biopsy

Answer: D

The definitive diagnosis of Hirschsprung’s disease is made by rectal biopsy. Samples of mucosa and submucosa are obtained at 1 cm, 2 cm, and 3 cm from the dentate line. In the neonatal period this biopsy can be performed at the bedside without anesthesia, because samples are taken in bowel that does not have somatic innervation and thus the procedure is not painful to the child. (See Schwartz 9thed., p 1436.)

17. Which of the following is a common site for a cystic hygroma?

A. Anterior mediastinum

B. Retroperitoneum

C. Anterior triangle of the neck

D. Axilla

Answer: D

Cystic hygroma (lymphangioma), occurring as a result of sequestration or obstruction of developing lymph vessels, occurs in approximately 1 in 12,000 births. Although the lesion can occur anywhere, the most common sites are in the posterior triangle of the neck, axilla, groin, and mediastinum. (See Schwartz 9th ed., p 1415.)

18. Which of the following is NOT typically associated with prune-belly syndrome?

A. Lax abdominal wall

B. Respiratory insufficiency

C. Dilated ureters

D. Bilateral undescended testes

Answer: B

Prune-belly syndrome is a disorder that is characterized by a constellation of symptoms including extremely lax lower abdominal musculature, dilated urinary tract including the bladder, and bilateral undescended testes (Fig. 39-7). (See Schwartz 9th ed., p 1443.)

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FIG. 39-7. Prune-belly (Eagle-Barrett) syndrome. Notice the flaccid abdomen.

19. Which of the following approaches is used for the repair of a type E (H-type) tracheoesophageal fistula?

A. Right thoracotomy

B. Left thoracotomy

C. Cervical incision

D. Median sternotomy

Answer: C

Patients with type E TEFs (commonly referred to as H-type) present beyond the newborn period. Presenting symptoms include recurrent chest infections, bronchospasm, and failure to thrive. The diagnosis can be suspected from the results of barium esophagography and confirmed by endoscopic visualization of the fistula. Surgical correction is generally possible through a cervical approach after placement of a balloon catheter across the fistula and requires mobilization and division of the fistula. Outcome is usually excellent. (See Schwartz 9th ed., p 1424.)

20. The most common associated anomaly in a boy with a high imperforate anus is

A. Congenital heart defect

B. Vertebral anomalies

C. Posterior urethral valves

D. Rectourethral fistula

Answer: D

In patients with imperforate anus, the rectum fails to descend through the external sphincter complex. Instead, the rectal pouch ends blindly in the pelvis, above or below the levator ani muscle. In most cases, the blind rectal pouch communicates more distally with the genitourinary system or with the perineum through a fistulous tract. Traditionally, the anatomic description of imperforate anus has characterized it as either ‘high’ or ‘low’ depending on whether the rectum ends above the levator ani muscle complex or partially descends through this muscle. Based on this classification system, in male patients with high imperforate anus the rectum usually ends as a fistula into the membranous urethra. In females, high imperforate anus often occurs in the context of a persistent cloaca. In both males and females, low lesions are associated with a fistula to the perineum. In males, the fistula connects with the median raphe of the scrotum or penis. In females, the fistula may end within the vestibule of the vagina, which is located immediately outside the hymen, or at the perineum. (See Schwartz 9th ed., p 1437.)

Congenital heart disease, vertebral anomalies, and posterior valves can all be seen in infants with imperforate anus and the VACTERL complex but these anomalies are not as common as the rectourethral fistula.

21. A newborn is evaluated for abdominal distention and bilious vomiting. Based on the KUB in Fig. 39-8, the initial intervention for this child should be a

A. Contrast enema

B. Upper gastrointestinal series

C. Rectal biopsy

D. Laparotomy

Answer: D

In cases in which the diagnosis of complete intestinal obstruction is determined based on the clinical picture and the presence of staggered air-fluid levels on plain abdominal films, the child can be brought to the operating room after appropriate resuscitation. In these circumstances, there is little extra information to be gained by performing a barium enema study. In contrast, when diagnostic uncertainty exists, or when distal intestinal obstruction is apparent, a barium enema study is useful to establish whether a microcolon is present and to diagnose the presence of meconium plugs, small left colon syndrome, Hirschsprung’s disease, or meconium ileus. (See Schwartz 9th ed., p 1427.)

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FIG. 39-8

22. The most appropriate intervention for a 3-month-old asymptomatic infant with a 1-cm firm mass in the center of the sternocleidomastoid muscle is

A. Fine-needle aspiration

B. Trucut needle biopsy

C. Surgical excision

D. Physical therapy

Answer: D

The presence of a lateral neck mass in infancy in association with rotation of the head toward the opposite side of the mass indicates the presence of congenital torticollis. This lesion results from fibrosis of the sternocleidomastoid muscle. The mass may be palpated in the affected muscle in approximately two thirds of cases. Histologically, the lesion is characterized by the deposition of collagen and fibroblasts around atrophied muscle cells. In the overwhelming majority of cases, physical therapy based on passive stretching of the affected muscle is of benefit. Rarely, surgical transection of the sternocleidomastoid muscle may be indicated. (See Schwartz 9th ed., p 1416.)

23. Orchidopexy (for an undescended testes)

A. Improves fertility

B. Decreases cancer risk

C. Increases the risk of trauma to the testes

D. Increases the risk of torsion of the testes

Answer: A

It is now established that cryptorchid testes show an increased predisposition to malignant degeneration. In addition, fertility is decreased when the testicle is not in the scrotum. For these reasons, surgical placement of the testicle in the scrotum (orchidopexy) is indicated. This procedure does improve the fertility potential, although it is never normal. Similarly, the testicle is still at risk of malignant change, although its location in the scrotum facilitates potentially earlier detection of a testicular malignancy. Other reasons to consider orchidopexy include the risk of trauma to a testicle located at the pubic tubercle, increased incidence of torsion, and the psychologic impact of an empty scrotum in a developing male. The reason for malignant degeneration has not been established, but the evidence points to an inherent abnormality of the testicle that predisposes it to incomplete descent and malignancy rather than malignancy as a result of an abnormal environment. (See Schwartz 9thed., p 1446.)

24. The initial treatment of an infant with complete bowel obstruction from uncomplicated meconium ileus is

A. NG decompression

B. Contrast enemas

C. Laparotomy and irrigation of the bowel lumen with N-acetylcysteine (purse-string enterotomy)

D. Laparotomy with resection of the distended distal ileum and creation of an ileostomy

Answer: B

The treatment strategy for infants with meconium ileus depends on whether the patient has complicated or uncomplicated meconium ileus. Patients with uncomplicated meconium ileus can be treated nonoperatively. A dilute water-soluble contrast agent is advanced through the colon under fluoroscopic control into the dilated portion of the ileum. The enema may be repeated at 12-hour intervals over several days until all the meconium is evacuated. If surgical intervention is required because of failure of contrast enemas to relieve obstruction, operative irrigation with dilute contrast agent, N-acetylcysteine (Mucomyst), or saline through a purse-string suture may be successful. Alternatively, resection of the distended terminal ileum is performed, and the meconium pellets are flushed from the distal small bowel. At this point, ileostomy and mucus fistula may be created from the proximal and distal ends, respectively. Alternatively, a Bishop-Koop anastomosis or an end-to-end anastomosis may be performed. (See Schwartz 9th ed., p 1429.)

25. What is the approximate success rate for air enema reduction of intussusceptions in children?

A. 10%

B. 25%

C. 50%

D. 75%

Answer: D

In the patient [with an intussusceptions who is] in stable condition, the air enema is both diagnostic and often curative. It constitutes the preferred method of diagnosis and nonoperative treatment of intussusception. Air is introduced with a manometer and the pressure that is administered is carefully monitored. Under most instances, this should not exceed 120 mmHg. Successful reduction is marked by free reflux of air into multiple loops of small bowel and symptomatic improvement as the infant suddenly becomes pain free. Unless both of these indications are observed, it cannot be assumed that the intussusception is reduced. If reduction is unsuccessful and the infant’s condition remains stable, the infant should be brought back to the radiology suite for a repeat attempt at reduction after a few hours. This strategy has improved the success rate of nonoperative reduction in many centers. In addition, hydrostatic reduction with barium may be useful if pneumatic reduction is unsuccessful. The overall success rate of radiographic reduction varies based on the experience of the center but is typically between 60 and 90%. (See Schwartz 9th ed., p 1433.)

26. The most common ovarian neoplasm in children is

A. Teratoma

B. Dysgerminoma

C. Granulosa-theca cell tumors

D. Epithelial tumors

Answer: A

Neoplastic lesions are categorized based on the three primordia that contribute to the ovary: mesenchymal components of the urogenital ridge, germinal epithelium overlying the urogenital ridge, and germ cells migrating from the yolk sac. The most common variety is germ cell tumors. Germ cell tumors are classified based on the degree of differentiation and the cellular components involved. The least differentiated tumors are the dysgerminomas, which share features similar to those of seminomas in males. Although these are malignant tumors, they are extremely sensitive to radiation and chemotherapy. The most common lesions are the teratomas, which may be mature, immature, or malignant. The degree of differentiation of the neural elements of the tumor determines the degree of immaturity. The sex cord stromal tumors arise from the mesenchymal components of the urogenital ridge. These include granulosa-theca cell tumors and Sertoli-Leydig cell tumors. These tumors often produce hormones that result in precocious puberty or hirsutism, respectively. Epithelial tumors, although rare, do occur in children. These include serous and mucinous cystadenomas. (See Schwartz 9thed., p 1446.)

27. The standard surgical procedure for a patient with confirmed Hirschsprung’s disease is

A. Transverse colostomy

B. “Leveling” colostomy

C. Primary pull-through in the newborn period

D. Irrigations with primary pull-through at age 3-6 months

Answer: C

It is now well established that a primary pull-through procedure can be performed safely, even in the newborn period. This approach follows the same treatment principles as a staged procedure and saves the patient from an additional operation. Many surgeons perform the intra-abdominal dissection using the laparoscope. This approach is especially useful in the newborn period, because it provides excellent visualization of the pelvis. (See Schwartz 9th ed., p 1436.)

28. The most common location for a congenital diaphragmatic hernia is

A. Left posterolateral

B. Right posterolateral

C. Left anteromedial

D. Right anteromedial

Answer: A

The most common variant of a congenital diaphragmatic hernia (CDH) is a posterolateral defect, also known as a Bochdalek’s hernia. This anomaly is encountered more commonly on the left (80 to 90% of cases). (See Schwartz 9th ed., p 1416.)

29. Which of the following indicates a poor prognosis in a patient with neuroblastoma?

A. Hyperdiploid DNA

B. Absence of N-myc amplification

C. Age 1 year

D. Age >13 years

Answer: D

A number of biologic variables have been studied in children with neuroblastoma. An open biopsy is often required to provide sufficient tissue for analysis. The presence of hyper-diploid tumor DNA is associated with a favorable prognosis, whereas N-myc amplification is associated with a poor prognosis regardless of patient age. The Shimada classification describes tumors as having either favorable or unfavorable histologic features based on the degree of differentiation, the mitosis-karyorrhexis index, and the presence or absence of schwannian stroma. In general, children of any age with localized neuroblastoma and infants 1 year of age with advanced disease and favorable disease characteristics have a high likelihood of disease free survival. By contrast, older children with advanced disease have a significantly decreased chance for cure even with intensive therapy. For example, aggressive multiagent chemotherapy has resulted in a 2-year survival rate of approximately 20% in older children with stage IV disease. Neuroblastoma in the adolescent has a worse long-term prognosis regardless of stage or site and, in many cases, a more prolonged course. (See Schwartz 9th ed., p 1450.)

30. Appropriate management of a stable child with a grade IV splenic injury is

A. Observation

B. Embolization

C. Splenorrhaphy

D. Splenectomy

Answer: A

The spleen is injured relatively commonly in blunt abdominal trauma in children. The extent of injury to the spleen is graded (Table 39-3), and management is governed by the injury grade. Current treatment involves a nonoperative approach in most cases, even for grade IV injuries, assuming the patient is hemodynamically stable. This approach avoids surgery in most cases. All patients should be placed in a monitored unit, and type-specific blood should be available for transfusion. When nonoperative management is successful, as it is in most cases, an extended period of bedrest is prescribed. This optimizes the chance for healing and minimizes the likelihood of reinjury. A typical guideline is to keep the child on extremely restricted activity for 2 weeks longer than the grade of spleen injury (i.e., a child with a grade IV spleen injury is prescribed 6 weeks of restricted activity). (See Schwartz 9th ed., p 1453, and Table 39-3.)

TABLE 39-3 Grading of splenic injuries

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31. Approximately what percentage of patients who have undergone a Kasai procedure for biliary atresia will be alive with their native liver 10 years after the procedure?

A. 10%

B. 25%

C. 33%

D. 50%

Answer: D

A recent review of the data of the Japanese Biliary Atresia Registry, which includes the results for 1381 patients, showed that the 10-year survival rate was 53% without transplantation and 66.7% with transplantation. (See Schwartz 9th ed., p 1440.)

32. Which of the following is NOT part of Cantrell’s pentalogy?

A. Omphalocele

B. Ectopia cordis

C. Posterolateral diaphragmatic hernia

D. Cardiac anomalies

Answer: C

Omphalocele has an incidence of approximately 1 in 5000 live births and occurs in association with special syndromes such as exstrophy of the cloaca (vesicointestinal fissure), the Beckwith-Wiedemann constellation of anomalies (macroglossia, macrosomia, hypoglycemia, visceromegaly, and omphalocele) and the Cantrell pentalogy (lower thoracic wall malformations such as cleft sternum, ectopia cordis, epigastric omphalocele, anterior midline diaphragmatic hernia, and cardiac anomalies). (See Schwartz 9th ed., p 1442.)

33. The optimal time for reduction and repair of a congenital diaphragmatic hernia is

A. At birth, after initial stabilization of the baby

B. Within the first 24 hours of life

C. Within the first 72 hours of life

D. None of the above

Answer: D

In the past, correction of the hernia was felt to be a surgical emergency, and these patients underwent surgery shortly after birth. It is now accepted that the presence of persistent pulmonary hypertension which results in right-to-left shunting across the open foramen ovale or the ductus arteriosus and pulmonary hypoplasia are the leading causes of cardiorespiratory insufficiency. Current management therefore is directed toward preventing or reversing the pulmonary hypertension and minimizing barotrauma while optimizing oxygen delivery. In patients who are not placed on ECMO, repair should be performed once the hemodynamic status has been optimized. (See Schwartz 9th ed., p 1417.)

34. Which of the following would be expected in a baby with delayed diagnosis of pyloric stenosis?

A. Hyperchloremia, low urine pH

B. Hyperchloremia, high urine pH

C. Hypochloremia, low urine pH

D. Hypochloremia, high urine pH

Answer: C

Infants with HPS develop a hypochloremic, hypokalemic metabolic alkalosis. The urine pH is high initially but eventually drops because hydrogen ions are preferentially exchanged for sodium ions in the distal tubule of the kidney as the hypochloremia becomes severe. (See Schwartz 9th ed., p 1426.)

35. Which of the following is associated with duodenal atresia?

A. Trisomy 13

B. Trisomy 16

C. Trisomy 18

D. Trisomy 21

Answer: D

Approximately one third of newborns with duodenal atresia have associated Down syndrome (trisomy 21). These patients should be evaluated for associated cardiac anomalies. (See Schwartz 9th ed., p 1427.)

36. The blood supply of a pulmonary sequestration is from the

A. Pulmonary artery

B. Bronchial artery

C. Innominate artery

D. Aorta

Answer: D

In pulmonary sequestration, a mass of lung tissue, usually in the left lower chest, lacks the usual connections to the pulmonary artery or tracheobronchial tree and its blood supply is derived directly from the aorta. There are two kinds of sequestration. In extralobar sequestration a small area of nonaerated lung is separated from the main lung mass, has a systemic blood supply, and usually is located immediately above the left diaphragm. It is commonly found in cases of CDH. Intralobar sequestration more commonly occurs within the parenchyma of the left lower lobe but also can occur on the right. (See Schwartz 9th ed., p 1418, and Fig. 39-9.)

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FIG. 39-9. Arteriogram showing large systemic artery supply to an intralobar sequestration of the left lower lobe.