Editing Pediatric Nursing – RN Practice Questions (section)

==Question 7==
A 4-week-old infant is admitted with a 5-day history of forceful vomiting after feedings. Which findings support a diagnosis of hypertrophic pyloric stenosis? '''Select all that apply.'''
# Bile-stained emesis
# Projectile vomiting followed by immediate hunger
# A firm, movable, olive-shaped mass in the right upper quadrant
# Serum chloride 88 mEq/L and serum bicarbonate 32 mEq/L
# Currant jelly stools
# Visible peristaltic waves moving across the upper abdomen

'''Answer:''' 2, 3, 4, and 6.

''Rationale:'' Pyloric stenosis obstructs at the gastric outlet, producing non-bilious projectile vomiting in an infant who remains hungry, a palpable olive-shaped pylorus, and visible left-to-right peristaltic waves. Persistent loss of gastric hydrochloric acid produces a hypochloremic, hypokalemic metabolic alkalosis, consistent with the low chloride and elevated bicarbonate in option 4. Option 1 is wrong because the obstruction is proximal to the ampulla of Vater, so emesis is non-bilious; bilious emesis suggests a distal obstruction such as malrotation with volvulus and is an emergency. Option 5 describes intussusception.