A 3-week-old male infant presents with projectile non-bilious vomiting, weight loss, and a palpable 'olive-shaped' mass in the right upper quadrant. Ultrasound shows pyloric muscle thickness of 4.2 mm and pyloric canal length of 19 mm. The MOST appropriate immediate pre-operative management is:
- A Proceed directly to Ramstedt pyloromyotomy without delay
- B Start nasogastric feeds and attempt medical management with atropine
- C Correct hyponatraemic hypochloraemic metabolic alkalosis with IV 0.9% saline + potassium chloride before surgery ✓
- D Upper GI contrast study to confirm the diagnosis before any intervention
Explanation
Hypertrophic pyloric stenosis (pyloric muscle thickness ≥4 mm and canal length ≥14 mm on ultrasound are diagnostic) causes persistent vomiting of gastric contents (HCl + K+), producing hypochloraemic, hypokalaemic metabolic alkalosis. This is a surgical emergency in terms of metabolic severity — pyloromyotomy (Ramstedt's operation) is curative but NOT urgent; surgery must be delayed until the fluid and electrolyte derangement is corrected with IV 0.9% saline and KCl. General anaesthesia in uncorrected alkalosis risks apnoea. Atropine may work but is not standard surgical practice. Ultrasound is diagnostic; contrast study is not needed.
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.