Intussusception - Clinical Features And Management

With intussusception, a portion of the bowel telescopes (invaginates) into an adjacent distal portion. Intussusception may be fatal, especially if treatment is delayed for a strangulated intestine.

Causes
Intussusception is most common in infants and is three times more common in males than in females. It typically occurs between ages 3 months and 3 years, with a peak incidence between ages 6 and 9 months.
Studies suggest that intussusception may be linked to viral infections because seasonal peaks are noted—in late spring and early summer, coinciding with the peak incidence of enteritis, and in midwinter, coinciding with the peak incidence of respiratory tract infections.
The cause of most cases of intussusception in infants is unknown. In older children, polyps, alterations in intestinal motility, hemangioma, lymphosarcoma, lymphoid hyperplasia, or Meckel’s diverticulum may trigger the process. In adults, intussusception usually results from benign or malignant tumors (65% of patients). It may also result from polyps, Meckel’s diverticulum, gastroenterostomy with herniation, or an appendiceal stump. In the elderly, decreased GI elasticity and motility can lead to intussusception.

Pathology

When a bowel segment (the intussusceptum) invaginates, peristalsis propels it along the bowel, pulling more bowel along with it; the receiving segment is the intussuscipiens. This invagination produces edema, hemorrhage from venous engorgement, incarceration, and obstruction. If treatment is delayed for longer than 24 hours, strangulation of the intestine usually occurs, with gangrene, shock, and perforation.

Clinical Features

In an infant or a child, intussusception produces four cardinal signs and symptoms:

1. intermittent attacks of severe colicky abdominal pain, which cause the child to scream, draw up his legs to his abdomen, turn pale and diaphoretic and, possibly, display grunting respirations (Between bouts of colic, the infant is commonly sleepy or lethargic.)
2. initially, vomiting of stomach contents; later, vomiting of bile-stained or fecal material
3. “currant jelly” stools, which contain a mixture of blood and mucus
4. tender, distended abdomen, with a palpable, sausage-shaped right upper quadrant mass; usually, the viscera are absent from the right lower quadrant.

In adults, intussusception produces nonspecific, chronic, and intermittent signs and symptoms, including colicky abdominal pain and tenderness, vomiting, diarrhea (occasionally constipation), bloody stools, and weight loss. Abdominal pain usually localizes in the right lower quadrant, radiates to the back, and increases with eating. Adults with severe intussusception may develop strangulation with excruciating pain, abdominal distention, and tachycardia.

Diagnosis
The following test results confirm intussusception:

• Barium enema confirms colonic intussusception when it shows the characteristic coiled-spring sign; it also delineates the extent of intussusception.
• Upright abdominal X-rays may show a soft-tissue mass and signs of complete or partial obstruction with dilated loops of bowel.
• White blood cell count up to 15,000/µl indicates obstruction; more than 15,000/µl, strangulation; more than 20,000/µl, bowel infarction.

Management
In children, therapy may include hydrostatic reduction or surgery. Surgery is indicated for children with recurrent intussusception, for those who show signs of shock or peritonitis, and for those in whom symptoms have been present longer than 24 hours. In adults, surgery is always the treatment of choice.

Hydrostatic reduction
During hydrostatic reduction, the radiologist drips a barium solution into the rectum from a height of not more than 3? (0.9 m); fluoroscopy traces the barium’s progress. If the procedure is successful, contrast flows freely into the ileum and the mass disappears. Inability to show this suggests incomplete reduction and necessitates surgical exploration.

Surgery
During surgery, manual reduction is attempted first. After compressing the bowel above the intussusception, the surgeon attempts to milk the intussusception back through the bowel. If manual reduction fails or if the bowel is gangrenous or strangulated, the surgeon performs a resection of the affectedbowel segment. An incidental appendectomy is also performed.