Intussusception

1. Definition
   1. Bowel 'telescopes' onto itself
2. Epidemiology
   1. Most common cause Intestinal Obstruction age <6 years
   2. Incidence: 1 to 4 in 1000 newborns
   3. Ages affected
      1. Rare before age 3 months
      2. Most common ages 3 to 12 months (66%)
      3. Less common after age 36 months
   4. Gender predominence: Males > Females by 3:1 ratio
3. Etiology
   1. Idiopathic (90%)
   2. Pathologic lesion at lead point of Intussusception
      1. Enlarged Peyer's Patch (follows recent gastrointestinal illness)
         1. Common cause
      2. Intestinal polyp
         1. Peutz-Jeghers Syndrome
         2. Juvenile Polyposis
         3. Familial Polyposis Coli
      3. Henoch-Schonlein Purpura
      4. Hemangioma
      5. Meckel's Diverticulum
      6. Lymphosarcoma
      7. Abdominal Trauma or foreign body
4. Risk Factors
   1. Cystic Fibrosis
   2. Indwelling gastrointestinal tubes
   3. Recent infection
      1. Upper Respiratory Infection
      2. Acute Gastroenteritis
5. Symptoms
   1. Child often appears well between episodes of pain
   2. Vomiting (delayed onset by 6-12 hours)
   3. Abdominal Pain
      1. Sudden onset
      2. Colicky with paroxysms of pain in 20 minute intervals (may flex knees to Abdomen in pain)
   4. Stool change
      1. Watery stools in first 12 to 24 hours
      2. Red Currant Jelly Stools (bloody mucus) later (occurs in 50% of cases)
6. Signs
   1. Lethargy may be only presenting finding (10% of cases)
   2. Evolution of abdominal examination
      1. Initial: Benign Abdomen
      2. Later: Abdominal distention with peritoneal signs
   3. Right upper quadrant abdominal mass
7. Differential Diagnosis
   1. Incarcerated Hernia
   2. Acute Gastroenteritis
   3. Testicular Torsion
   4. Acute Appendicitis
   5. Meckel diverticulum
   6. Mesenteric lymphadenitis
   7. Small Bowel Obstruction
   8. Abdominal Trauma
   9. Volvulus
8. Imaging
   1. Ultrasound
      1. May be preferred first screening for Intussusception
   2. Contrast Enema
      1. Sensitivity: 95% of Intussusception
      2. Curative in most early cases of Intussusception
      3. Contraindications
         1. Patient unstable
         2. Surgical Abdomen
   3. Abdominal XRay signs of Intussusception (variably present)
      1. Right lower quadrant abdominal mass
      2. Absent bowel gas in right upper quadrant
      3. Target sign or Cresent sign
         1. Air trapped between the bowel lumens
9. Management
   1. Immediate contrast enema if no contraindication
   2. Surgical consultation
   3. Consider prophylactic antibiotics prior to attempted reduction
   4. Admit and observe for recurrence for at least 24 hours
      1. Due to risk of recurrence in 5-10% of cases
10. Course and Prognosis
    1. Mortality
       1. Mortality 1 to 3% with early treatment
       2. Fatal if not treated within 2-5 days
    2. Recurrence in 3 to 11% of cases (most in first day)
11. References
    1. Bisset (1988) Radiology 168(1): 141-5
    2. West (1987) Surgery 102(4): 704-10
    3. Yamamoto (1997) Am J Emerg Med 15(3):293-8