Paediatric Surgery: Neonatal Vomiting and Childhood Emergencies
Paediatric Surgery tests congenital and acquired surgical conditions of neonates and children. The MCQ favours age-specific presentations, fluid and electrolyte correction, and recognition of which vomiting is surgical.
Core rules
- Neonatal bilious vomiting is malrotation with midgut volvulus until excluded. It is a surgical emergency; arrange urgent upper gastrointestinal contrast and proceed to laparotomy.
- Pyloric stenosis: presents at 3 to 6 weeks with non-bilious projectile vomiting, hunger and weight loss. Biochemistry shows hypochloraemic hypokalaemic metabolic alkalosis with paradoxical aciduria. Ultrasound shows pyloric thickness of at least 3 mm and length of at least 15 mm. Correct fluids before Ramstedt pyloromyotomy.
- Intussusception: typically 6 to 36 months, with colicky pain, drawing up of the legs, a sausage-shaped mass and redcurrant jelly stool. Ultrasound shows a target sign. Air or contrast enema reduction is used if the child is stable without peritonitis.
- Hirschsprung disease: delayed meconium, abdominal distension and enterocolitis. Rectal biopsy is the gold standard.
- Congenital diaphragmatic hernia: scaphoid abdomen and respiratory distress; intubate, decompress the stomach with a nasogastric tube, and avoid bag-mask ventilation.
- Inguinal hernia in infants: high risk of incarceration; repair promptly.
- Testicular torsion: acute scrotum, high-riding testis and absent cremasteric reflex; emergency exploration is required.
Worked example
A 6-week-old boy has projectile non-bilious vomiting after feeds, weight loss and visible gastric waves. Biochemistry shows hypochloraemic hypokalaemic metabolic alkalosis. Ultrasound confirms pyloric stenosis.
Reasoning: the vomiting is non-bilious, which fits pyloric stenosis rather than malrotation. The alkalosis is due to loss of gastric acid, and the paradoxical aciduria reflects potassium depletion. Correct with 0.9% saline plus potassium chloride before surgery; Ramstedt pyloromyotomy is then performed.
Traps
- Bilious vomiting is not pyloric stenosis; it suggests malrotation until proven otherwise.
- Do not perform contrast enema reduction if there is perforation or peritonitis.
- Intussusception can recur after reduction; recurrence still requires reassessment.
- In congenital diaphragmatic hernia, avoid prolonged bag-mask ventilation because it worsens bowel distension.