A 4-week-old male infant presents with non-bilious projectile vomiting after every feed. He is eagerly hungry after vomiting. Examination reveals visible peristalsis and a palpable olive-shaped mass in the right upper quadrant. Ultrasound confirms pyloric canal thickness of 4 mm and length of 18 mm. The diagnosis is:
- A Duodenal atresia
- B Pyloric atresia
- C Hypertrophic pyloric stenosis ✓
- D Gastroesophageal reflux
Correct answer: C. Hypertrophic pyloric stenosis
Explanation
Non-bilious projectile vomiting in a 3-6-week-old male infant with a palpable pyloric 'olive' mass and ultrasound criteria (muscle thickness ≥4 mm, canal length ≥17 mm) is diagnostic of hypertrophic pyloric stenosis. The metabolic consequence is a hypokalaemic, hypochloraemic metabolic alkalosis due to loss of HCl. After correction of electrolyte imbalance and dehydration, Ramstedt's pyloromyotomy is the definitive treatment. Duodenal atresia presents in the first 24-48 hours with bilious vomiting and a double-bubble sign on X-ray.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.