Intussusception

A 24 month old male child presents with intermittent severe abdominal pain and multiple episodes of vomiting over the past 8 hours. The pain is colicky, lasting a few minutes, resolving spontaneously, and recurring every 15 to 30 minutes. During episodes, the child draws his knees to his chest and cries intensely. His mother reports red, mucus-like stool (currant jelly stool) in the diaper. He had a recent viral illness one week ago. On examination, the child is irritable. The abdomen is soft with mild distension, and a sausage-shaped mass is palpable in the right upper quadrant. Abdominal ultrasonography shows a target sign. Diagnosis?

Diagnosis is Intussusception.

1. Definition

Intussusception is the telescoping of a proximal segment of intestine into a distal segment, leading to bowel obstruction and compromised blood supply.

2. Etiology

1. Idiopathic, most common in children
2. Hypertrophy of Peyer patches following viral infection
3. Pathologic lead points:
• Meckel diverticulum
• Polyps or tumors

3. Pathophysiology

1. Invagination of bowel leads to obstruction
2. Venous congestion causes edema
3. Progression to ischemia
4. Mucosal bleeding occurs
5. Formation of currant jelly stool

4. Clinical Features

4.1 Core Features

1. Intermittent colicky abdominal pain
2. Vomiting, initially non-bilious, later may become bilious
3. Currant jelly stool

Note: The classic triad is present in less than 40 percent of cases

4.2 Associated Features

1. Child draws knees to chest during pain
2. Sausage-shaped abdominal mass, usually in right upper quadrant
3. Lethargy or altered responsiveness
4. Dance sign, empty right lower quadrant, may be present but is not reliable
5. Often preceded by viral illness

5. Diagnosis

5.1 Imaging

1. Ultrasound, first-line investigation
• Target sign or donut sign
2. Abdominal X-ray
• May show bowel obstruction
• Used to assess for perforation

5.2 Key Diagnostic and Therapeutic Tool

1. Air (pneumatic) enema
• Confirms diagnosis
• First-line treatment

6. Management

6.1 Initial Stabilization

1. Intravenous fluids
2. Electrolyte correction
3. Nasogastric decompression if needed

6.2 Definitive Treatment

1. Air enema reduction, first-line
2. Surgical intervention if:
• Enema reduction fails
• Peritonitis
• Perforation
• Hemodynamic instability

7. Complications

1. Bowel ischemia and necrosis
2. Perforation
3. Peritonitis
4. Recurrence, occurs in approximately 5 to 10 percent

8. Key Clinical Insight

Young child, typically between 6 and 18 months, with intermittent colicky abdominal pain, knee-to-chest posture, currant jelly stool, and target sign on ultrasound strongly indicates intussusception

9. Exam Level Pearls

1. Intermittent colicky pain with knee-to-chest posture is classic
2. Currant jelly stool is a late finding
3. Ultrasound target sign confirms diagnosis
4. Air enema is diagnostic and first-line treatment
5. Lethargy can be a key presenting feature