GIT 1

Omphalocele

  • Definition: A congenital abdominal wall defect where the intestines, liver, and sometimes other organs remain outside the abdomen in a sac made of peritoneum and amnion, through the umbilical ring.

  • Pathophysiology: Failure of the intestines to return to the abdominal cavity during fetal development (10th–12th week of gestation).

  • Types/Classification:

    • Based on size: Small or giant (involving liver).

    • Associated anomalies: Chromosomal abnormalities (e.g., trisomy 13, 18, 21).

  • Treatment:

    • Pharmacological: Antibiotics to prevent infection.

    • Non-Pharmacological: Surgical repair (primary closure or staged repair depending on size).

  • Clinical Features:

    • Translucent membranous sac containing abdominal contents.

    • Umbilical cord attached to the sac.

    • Associated anomalies (e.g., cardiac or chromosomal defects).

  • Complications:

    • Infection or rupture of the sac.

    • Malnutrition.

    • Associated congenital anomalies (cardiac, chromosomal).

2. Gastroschisis

  • Definition: A congenital defect characterized by the protrusion of abdominal organs (usually intestines) through an opening in the abdominal wall, typically to the right of the umbilicus, without a protective sac.

  • Pathophysiology: Disruption in the closure of the lateral body folds during embryogenesis, often due to vascular compromise.

  • Types/Classification: No major classification; focus on severity (simple vs. complex).

  • Treatment:

    • Pharmacological: Antibiotics, fluid resuscitation.

    • Non-Pharmacological: Surgical repair (staged silo closure or primary closure).

  • Clinical Features:

    • Exposed intestines without a sac.

    • Bowel loops thickened and inflamed.

    • No associated chromosomal abnormalities (in contrast to omphalocele).

  • Complications:

    • Bowel ischemia or necrosis.

    • Short bowel syndrome.

    • Sepsis due to exposed intestines.

3. Meckel's Diverticulum

  • Definition: A congenital remnant of the vitelline duct forming a true diverticulum in the ileum, often containing ectopic gastric or pancreatic tissue.

  • Pathophysiology: Incomplete obliteration of the vitelline duct during embryonic development, leading to formation of a pouch.

  • Types/Classification: None, but often described by the “Rule of 2s” (2% prevalence, 2 feet from ileocecal valve, 2 inches in length, symptomatic before 2 years of age).

  • Treatment:

    • Pharmacological: Proton pump inhibitors (if ulceration is present).

    • Non-Pharmacological: Surgical resection (diverticulectomy or segmental resection).

  • Clinical Features:

    • Painless rectal bleeding (melena or hematochezia).

    • Intestinal obstruction (volvulus or intussusception).

    • Abdominal pain mimicking appendicitis.

  • Complications:

    • Obstruction.

    • Diverticulitis.

    • Perforation or ulceration of ectopic gastric mucosa.

4. Pyloric Stenosis

  • Definition: Hypertrophy of the pyloric muscle causing gastric outlet obstruction in infants.

  • Pathophysiology: Hypertrophy and hyperplasia of the circular muscle of the pylorus result in narrowing of the pyloric channel, leading to obstruction of gastric emptying.

  • Types/Classification: No major classification.

  • Treatment:

    • Pharmacological: Electrolyte and fluid correction (e.g., saline, potassium).

    • Non-Pharmacological: Surgical pyloromyotomy (Ramstedt procedure).

  • Clinical Features:

    • Projectile, non-bilious vomiting after feeding.

    • Palpable “olive-shaped” mass in the right upper quadrant.

    • Visible peristaltic waves on the abdomen.

  • Complications:

    • Severe dehydration and electrolyte imbalance (hypochloremic, hypokalemic metabolic alkalosis).

    • Weight loss and failure to thrive.

5. Hirschsprung Disease

  • Definition: A congenital disorder characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the distal colon, leading to functional obstruction.

  • Pathophysiology: Arrest in migration of neural crest cells during embryogenesis, resulting in an aganglionic segment of the colon that cannot relax, causing obstruction.

  • Types/Classification:

    • Based on length: Short-segment (most common) vs. long-segment.

    • Total colonic aganglionosis (rare).

  • Treatment:

    • Pharmacological: Supportive therapy, including hydration and rectal irrigations.

    • Non-Pharmacological: Surgical resection of the aganglionic segment (pull-through procedures such as Soave or Duhamel).

  • Clinical Features:

    • Delayed passage of meconium (>48 hours after birth).

    • Abdominal distension and bilious vomiting.

    • Chronic constipation and failure to thrive in older children.

  • Complications:

    • Enterocolitis (life-threatening).

    • Intestinal perforation.

    • Chronic constipation and fecal incontinence post-surgery.