STEPHEN LUDWIG BRANDON C. KU
HISTORY OF PRESENT ILLNESS
A 3-month-old female was referred by her pediatrician to the emergency department for failure to thrive (FTT). She has had problems gaining weight since 1-2 months of age and has been followed weekly for weight checks with poor weight gain. She was initially breast fed but had poor latching-on and was changed to Enfamil® with and then without Fe, Lactofree®, Prosobee®, and now is on Similac® with Fe. The family has tried thickening feeds with cereal and bananas with no improvement. She takes 4 ounces per feeding and is burped every 2 ounces. Intake is 28 ounces per day. She spits and vomits, sometimes forcefully, 1-2 oz per feed. The emesis was nonbloody, nonbilious, and occasionally projectile. The emesis has become worse over the last month. There has been no diarrhea. For the last 3 days, she has been less active than usual with glassy-appearing eyes. Urine output has decreased (only two wet diapers today compared to her usual 7-10 per day).
The infant was born to a 16-year-old mother. The mother had prenatal care since the second month of pregnancy. The child was born at term with a weight of 3440 g. There were no postnatal complications and she was discharged at 39 hours of age. Development had been normal. She rolled from front to back at 6 weeks of life. She received no medications. Her immunizations were current. The family history was unremarkable.
T 37°C; HR 129 bpm; RR 18/min; BP 68/41 mmHg; Weight 3.89 kg (50th percentile for a 1-month-old child)
On examination, the child was crying but consolable. She had markedly decreased subcutaneous fat. The anterior fontanel was sunken. The pupils were reactive to light. There was no nasal discharge.
The heart and lungs were normal to auscultation. The abdomen was scaphoid with visible peristaltic waves. The spleen tip was palpable below the left costal margin. The extremities were slightly cool with 2-3 second capillary refill. The neurologic examination was normal.
White blood cells 8.800/mm3 (1% band forms, 59% segmented neutrophils, and 30% lymphocytes, and 10% monocytes).
Hemoglobin, 12.9 mg/dL; platelets 195 000/mm3; sodium, 129 mEq/L; potassium, 4.8 mEq/L; chloride, 65 mEq/L; bicarbonate, 53 mEq/L; blood urea nitrogen, 48 mg/dL; creatinine, 1.4 mg/dL; serum transaminases were normal; other studies included a cholesterol 206 and triglycerides 313.
COURSE OF ILLNESS
In the emergency department the patient received approximately 40 mL/kg of normal saline. She was admitted to the intensive care unit due to rapid but periodic breathing. An abdominal radiograph (Figure 6-4) revealed a markedly distended stomach with a paucity of bowel gas pattern beyond the stomach. Abdominal ultrasound (Figure 6-5) revealed the diagnosis.
FIGURE 6-4. Abdominal radiograph.
FIGURE 6-5. Abdominal ultrasound.
DISCUSSION CASE 6-5
The differential diagnosis in this case included some form of upper bowel obstruction. There was a marked hypochloremic alkalosis to support this kind of loss along with the associated history. Severe gastroesophageal reflux, gastric outlet obstruction, pyloric stenosis, or some kind of duodenal anomaly (e.g., duplication) was possible. The upper gastrointestinal radiograph delineated the lesion of pyloric stenosis. The electrolyte disturbance is characteristic of an upper bowel atresia with loss of sodium, chloride, and hydrogen ion.
The abdominal ultrasound showed a thickened and elongated pylorus, with a maximal muscle length measuring 19 mm (Figure 6-5). The maximal muscle thickness was 5 mm. The gastric antrum was also imaged and there was evidence of significant fluid and debris from prior oral feeding. These findings were consistent with the diagnosis of pyloric stenosis. Once the patient’s metabolic derangement was corrected, she was taken to the operating room for a pyloromyotomy. The postoperative course was uneventful. This case was unusual in terms of the late onset of pyloric stenosis. Most cases are identified in the first 3-6 weeks of life.
INCIDENCE AND EPIDEMIOLOGY OF PYLORIC STENOSIS
Pyloric stenosis occurs in males 1:200 and in females 1:1000. The mode of inheritance is polygenic and modified by sex. The findings are associated with smaller family size and higher socioeconomic status. It is more common in African-Americans and Asians.
The clinical presentation is based on vomiting (often projectile in nature), failure to gain weight, and constipation. There are no other associated symptoms. On examination, the hypertrophied pyloric muscle (“olive”) is occasionally palpated in the right upper quadrant. This examination is best performed after the stomach has been emptied by means of a nasogastric tube. However, diagnosis rarely relies on clinical examination alone.
The palpation of the pyloric olive is often difficult and examiner dependent.
Serum electrolytes. Electrolytes reveal a hypochloremic metabolic alkalosis.
Abdominal ultrasound. Ultrasound typically reveals thickening of the pyloric muscle wall. When a broader differential diagnosis is being considered an upper gastrointestinal barium study should be considered. With the widespread availability of abdominal ultrasound, metabolic derangements at presentation are less common than in the past.
The treatment is a simple pyloromyotomy, which opens the pyloric channel and allows the passage of food into the small bowel. This is a surgery that may be performed with laparoscopic technique. The symptoms resolve within a few days postoperatively. There are no long-term complications and patients may be discharged postoperatively when they are able to tolerate feeding.
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