🔑 Key Learning

  • Common causes of vomiting, constipation, and obstruction in neonates and infants include pyloric stenosis, Hirschsprung’s, and duodenal atresia.
  • Intussusception presents classically with episodic pain and redcurrant jelly stool.
  • Toddler’s diarrhoea is benign and diagnosed clinically (peas and carrot stools)
  • Always consider surgical referral for suspected obstruction or failure to pass meconium.

  

🥣 Infantile Hypertrophic Pyloric Stenosis

🧬 Pathophysiology

  • Hypertrophy of the circular muscle of the pylorus causes gastric outlet obstruction.

👀 Clinical Features

  • Age: 3–8 weeks
  • Projectile, non-bilious vomiting within minutes of feeding
  • Constipation, FTT
  • Palpable ‘olive’ mass in RUQ
  • Visible gastric peristalsis

🧪 Investigations

  • 1st line: Abdominal USS: thickened pyloric muscle
  • Biochemistry: Hypochloraemic, hypokalaemic metabolic alkalosis

💊 Management

  • Ramstedt pyloromyotomy

   

🎯 Intussusception

🧬 Pathophysiology

  • Telescoping of proximal bowel into distal segment → obstruction, ischaemia
  • Majority of cases occur in association with or following viral gastroenteritis/URTI
Olek Remesz (wiki-pl: Orem, commons: Orem), CC BY-SA 3.0 , via Wikimedia Commons

👀 Clinical Features

  • Peak: 3–18 months
  • Colicky episodic pain, drawing up legs
  • Redcurrant jelly stool
  • Palpable sausage-shaped mass (RUQ)
  • Bilious vomiting, distension if progressed

🧪 Investigations

  • USS: Target sign
  • Contrast enema (diagnostic & therapeutic): Coiled spring appearance - gold standard. 

💊 Management

  • 1st Line: Therapeutic enema - air/water/contrast pumped into the colon, in an attempt to reduce the invagination, and restore the bowel to its normal position
  • Surgery if unsuccessful or peritonitic

  

🌊 Duodenal Atresia

👀 Clinical Features

  • Bilious vomiting within 48h of birth, begins following first oral feed
  • Polyhydramnios antenatally

🧪 Investigations

  • AXR: Double bubble sign

💊 Management

  • Surgical: Duodenoduodenostomy

   

🥦 Toddler’s Diarrhoea (Chronic Non-Specific)

👀 Clinical Features

  • A non-specific, chronic diarrhoea which most commonly affects children between 6 months and 5 years of age. 
  • Loose stools with undigested food (e.g. ‘peas and carrot stools’)
  • Colicky pain, increased flatus
  • Otherwise well and thriving with good development/growth. 

💊 Management

  • Reassurance
  • Dietary: Reduce juice/milk, increase fat
  • Loperamide rarely needed

   

🚫 Hirschsprung’s Disease

🧬 Pathophysiology

  • Absence of ganglion cells in bowel (usually rectosigmoid) → functional obstruction

👀 Clinical Features

Neonates:

  • Delayed meconium (>48 hrs), abdominal distension, bilious vomiting
  • Older children:
    • Chronic constipation since birth
    • Poor response to laxatives
    • FTT

🧪 Investigations

  • AXR: Obstruction
  • Rectal biopsy: Absence of ganglia

File:Hirschsprungs.jpg

AXR in Hirschprung's. Public domain.

💊 Management

  • Surgical resection of aganglionic segment

   

📝 Exam Clues & Clinchers

  • Pyloric stenosis: 3–8-week-old with projectile vomiting, palpable olive mass
    • 1st line invx: Ultrasound 
  • Intussusception: Intermittent colicky pain + redcurrant jelly stool
    • Diagnostic/therapeutic enema
  • Duodenal atresia: Bilious vomiting 24-48hrs after birth + double bubble sign on AXR
  • Hirschsprung’s: No meconium in first 48 hrs, chronic constipation
    • Rectal biopsy!
  • Toddler’s diarrhoea: Well child, undigested food in stool, resolves with age