GASTRO INTESTINAL DISORDERS.
Hypertrophic Pyloric Stenosis (HPS)
Definition:
Hypertrophic pyloric stenosis is a thickening of the pyloric muscle, leading to gastric outlet obstruction in infants.
Causes & Risk Factors:
- Firstborn male infants (most common)
- Genetic predisposition
- Macrolide antibiotics (Erythromycin exposure in neonates)
Signs & Symptoms:
- Projectile, non-bilious vomiting after feeding
- Palpable “olive-shaped” mass in RUQ
- Visible peristaltic waves after feeding
- Severe dehydration and metabolic alkalosis
Complications:
- Severe dehydration
- Electrolyte imbalance (Hypokalemic hypochloremic metabolic alkalosis)
Diagnosis:
- Ultrasound – “Target sign” (Thickened pylorus, >4mm muscle thickness)
- Barium swallow – “String sign” (narrow pyloric channel)
Management:
- IV fluid resuscitation (correct dehydration)
- Pyloromyotomy (Ramstedt’s procedure)
Hirschsprung’s Disease
Definition:
A congenital disorder characterized by absence of ganglion cells in the distal colon, leading to intestinal obstruction due to lack of peristalsis.
Causes:
- Mutation in RET proto-oncogene
- More common in males
- Associated with Down syndrome
Signs & Symptoms:
- Failure to pass meconium within 48 hours
- Chronic constipation
- Abdominal distension
- Bilious vomiting
- Ribbon-like stools in older children
Complications:
- Enterocolitis (toxic megacolon)
- Bowel perforation
Diagnosis:
- Rectal biopsy – Absence of ganglion cells (Gold standard)
- Barium enema – “Transition zone”
Management:
- Surgical resection of aganglionic segment (Swenson or Duhamel procedure)
- Temporary colostomy (if needed)
Intussusception
Definition:
A telescoping of one segment of the intestine into another, leading to intestinal obstruction and ischemia.
Causes & Risk Factors:
- Most common in infants 6–12 months
- Recent viral infections (Rotavirus, Adenovirus → lymphoid hyperplasia)
- Lead points: Meckel’s diverticulum, polyps, tumors
Signs & Symptoms:
- Colicky abdominal pain (intermittent crying episodes)
- Sausage-shaped mass in RUQ
- “Currant jelly stools” (bloody mucus stools)
- Bilious vomiting
Complications:
- Bowel necrosis and perforation
- Septic shock
Diagnosis:
- Ultrasound – “Target sign” (concentric layers of bowel)
- Barium or air enema (Diagnostic & therapeutic)
Management:
- Air or barium enema reduction (first-line treatment)
- Surgical reduction (if enema fails or perforation occurs)
Meckel’s Diverticulum
Definition:
A congenital remnant of the vitelline duct, containing ectopic gastric or pancreatic tissue, leading to bleeding or obstruction.
Rule of 2’s:
- 2% prevalence
- 2 feet from the ileocecal valve
- 2 inches in length
- 2 types of ectopic tissue (Gastric, Pancreatic)
- 2 years old (common presentation age)
Signs & Symptoms:
- Painless lower GI bleeding (melena, hematochezia)
- Intestinal obstruction (volvulus, intussusception)
- Periumbilical pain mimicking appendicitis
Complications:
- Perforation
- Iron deficiency anemia
Diagnosis:
- Technetium-99m pertechnetate scan (“Meckel’s scan”)
Management:
- Surgical excision (if symptomatic)
Gastroesophageal Reflux Disease (GERD) in Infants
Definition:
GERD is chronic acid reflux due to lower esophageal sphincter immaturity, causing regurgitation and feeding difficulties.
Causes:
- Prematurity
- Neurological impairment (Cerebral palsy)
- Overfeeding
Signs & Symptoms:
- Frequent post-feeding regurgitation
- Irritability during feeding
- Failure to thrive
- Coughing, wheezing (aspiration pneumonia)
Complications:
- Esophagitis
- Barrett’s esophagus (chronic cases)
Diagnosis:
- Clinical history
- pH probe study (Gold standard)
- Upper GI endoscopy (if complications suspected)
Management:
- Lifestyle modifications (Small frequent feeds, upright positioning after feeds)
- Medications (PPIs – Omeprazole, H2 blockers – Ranitidine)
- Surgical fundoplication (if refractory to treatment)
Necrotizing Enterocolitis (NEC)
Definition:
A life-threatening neonatal intestinal condition involving ischemic necrosis, most commonly seen in preterm infants.
Risk Factors:
- Prematurity (<32 weeks GA)
- Formula feeding (instead of breastfeeding)
- Perinatal hypoxia
Signs & Symptoms:
- Abdominal distension, tenderness
- Bilious vomiting
- Bloody stools (Hematochezia)
- Lethargy, apnea, shock (severe cases)
Complications:
- Intestinal perforation
- Sepsis, DIC
Diagnosis:
- Abdominal X-ray – “Pneumatosis intestinalis” (gas within intestinal wall)
- Blood culture (for sepsis workup)
Management:
- NPO (bowel rest), Total Parenteral Nutrition (TPN)
- IV antibiotics (Ampicillin + Gentamicin + Metronidazole)
- Surgery (if perforation or necrosis is present)
Key Points for Competitive Exams
✔️ Most common cause of intestinal obstruction in infants? – Intussusception
✔️ Projectile non-bilious vomiting in infants? – Pyloric Stenosis
✔️ Failure to pass meconium within 48 hours? – Hirschsprung’s Disease
✔️ Rule of 2’s applies to? – Meckel’s Diverticulum
✔️ Gold standard test for GERD in infants? – pH probe study
✔️ Most common cause of lower GI bleeding in children? – Meckel’s Diverticulum
✔️ Most specific sign of NEC on X-ray? – Pneumatosis intestinalis
✔️ Best initial treatment for intussusception? – Air/Barium enema
Intestinal Obstruction
Definition:
Intestinal obstruction is a blockage in the intestines that prevents the passage of food, fluids, and gas, leading to abdominal distension, vomiting, and constipation.
Types of Intestinal Obstruction:
- Mechanical Obstruction – Physical blockage of the intestines
- Congenital causes: Hirschsprung’s disease, Meconium ileus, Intussusception, Malrotation with volvulus, Congenital atresia (duodenal, jejunal, ileal, colonic)
- Acquired causes: Adhesions (post-surgical), Hernias, Tumors, Foreign body ingestion
- Functional Obstruction (Paralytic Ileus) – Lack of peristalsis
- Causes: Neonatal sepsis, Hypokalemia, Peritonitis, Post-operative state
Signs & Symptoms:
- Abdominal distension
- Bilious vomiting (greenish in proximal obstruction)
- Failure to pass meconium (in neonates)
- Constipation or obstipation (severe cases)
- Visible peristalsis (in mechanical obstruction)
- Hyperactive bowel sounds (early stage) → Absent sounds (late stage)
Complications:
- Bowel ischemia and necrosis
- Perforation leading to peritonitis
- Sepsis and dehydration
Diagnosis:
- X-ray Abdomen – “Air-fluid levels”
- Ultrasound – “Target sign” in intussusception
- Barium enema – To differentiate mechanical obstruction causes
- CT scan – To detect volvulus or tumors
Management:
- NPO (Nil Per Oral) and IV fluids
- Nasogastric decompression (NG tube)
- Antibiotics (if perforation or infection suspected)
- Surgical correction (for congenital obstructions, volvulus, intussusception)
Malabsorption Syndrome
Definition:
Malabsorption syndrome is a disorder in which the intestine cannot properly absorb nutrients, leading to malnutrition, diarrhea, and growth failure.
Types of Malabsorption Syndromes:
- Carbohydrate Malabsorption – Lactose intolerance, Sucrase-isomaltase deficiency
- Fat Malabsorption – Cystic fibrosis, Biliary atresia, Pancreatic insufficiency
- Protein Malabsorption – Celiac disease, Short bowel syndrome
- Vitamin/Mineral Malabsorption – Iron deficiency (Celiac disease), Vitamin B12 deficiency (Pernicious anemia)
Common Causes:
- Celiac Disease (Gluten-sensitive enteropathy) – Autoimmune reaction to gluten
- Cystic Fibrosis (CF) – Pancreatic enzyme deficiency causing fat malabsorption
- Tropical Sprue – Infection-related malabsorption in tropical regions
- Lactose Intolerance – Deficiency of lactase enzyme causing bloating and diarrhea
- Giardiasis (Parasitic Infection) – Leads to fat and vitamin B12 malabsorption
Signs & Symptoms:
- Chronic diarrhea (steatorrhea – foul-smelling, greasy stools)
- Failure to thrive, weight loss
- Abdominal bloating, flatulence
- Vitamin deficiencies:
- Vitamin A deficiency – Night blindness
- Vitamin D deficiency – Rickets
- Vitamin K deficiency – Bleeding tendencies
- Vitamin B12 deficiency – Anemia, Neuropathy
Complications:
- Severe malnutrition and growth failure
- Electrolyte imbalance and dehydration
- Rickets and osteoporosis (due to vitamin D deficiency)
- Neurological deficits (due to vitamin B12 deficiency)
Diagnosis:
- Stool analysis – Sudan stain for fat malabsorption
- D-xylose test – Tests carbohydrate absorption
- Lactose hydrogen breath test – For lactose intolerance
- Anti-TTG IgA (Tissue Transglutaminase Antibody) – Celiac disease
- Small bowel biopsy – Gold standard for Celiac disease
Management:
- Dietary modifications:
- Gluten-free diet (for Celiac disease)
- Lactose-free diet (for lactose intolerance)
- High-protein, high-calorie diet
- Pancreatic enzyme replacement (Cystic Fibrosis)
- Vitamin and mineral supplementation
- Antibiotics for tropical sprue and bacterial overgrowth syndrome
Key Points for Competitive Exams
✔️ Most common cause of intestinal obstruction in neonates? – Hirschsprung’s disease
✔️ Most common cause of intestinal obstruction in children 6–12 months? – Intussusception
✔️ Gold standard test for Celiac disease? – Small bowel biopsy
✔️ First-line test for malabsorption? – Stool fat analysis (Sudan stain)
✔️ Most common parasitic cause of malabsorption? – Giardiasis
✔️ Vitamin deficiency associated with Cystic Fibrosis? – Fat-soluble vitamins (A, D, E, K)
✔️ Best initial management for mechanical intestinal obstruction? – NG tube decompression and IV fluids