Disorders of the Jejunum and Ileum

Disorders of the jejunum and ileum may exist alone or with disorders of other viscera (such as gastroenteritis or Crohn's disease). Many of these disorders are treated medically, but some are also treated surgically and must be considered in the differential diagnosis of the surgical abdomen.

Disorders of the jejunum and ileum may be caused by acquired or iatrogenic factors; inflammatory or toxic agents; malabsorption; motility disorders; or tumors. Meckel's diverticulum, the only congenital lesion common in elderly patients, is nearly always an incidental finding, and symptoms are rare in the elderly.

Acquired Lesions

The most common acquired lesion is diverticulosis, in which sac-like projections of the mucosa protrude through the muscularis of the bowel. These projections are most common in the jejunum of elderly patients. Diverticulosis may be asymptomatic or may be associated with massive bleeding, malabsorption, or inflammation (diverticulitis). In cases of massive bleeding, locating the involved bowel segment is desirable. Selective arteriography, which may be combined with exploratory laparotomy, is the best diagnostic tool. It allows resection of the shortest possible segment of bowel. Perforation is uncommon, but if it occurs, resection and reanastomosis are the procedures of choice.

Iatrogenic Lesions

The most common iatrogenic lesions are excessive enterectomy, radiation enterocolitis, and blind loop syndrome.

Radiation enterocolitis: The small intestine is damaged by 50 Gy; the colon is slightly more resistant. The symptoms of radiation enterocolitis are indistinguishable from those of chronic intestinal obstruction. Radiation enterocolitis produces bleeding and diarrhea. Conservative therapy usually is indicated at the outset, because some acute symptoms may subside with IV alimentation and restriction of oral intake.

Minor colonic ulceration may be treated with a bland diet and psyllium hydrophilic mucilloid. Surgery to resect bowel is often unsuccessful, because radiation diminishes the intestinal blood supply so that anastomoses tend to heal poorly. Furthermore, because dense pelvic adhesions are likely, dissection is arduous; leakage and fistula formation are occasional sequelae. Thus, resection may be difficult or impossible, and palliative enteroenterostomy may be required. However, in severe cases, resection of the involved segment with reanastomosis may be possible; in other cases, a permanent colostomy may have to be combined with resection of the involved rectum or colon.

Blind loop syndrome: This syndrome develops when a surgeon inadvertently creates a bowel loop in which intestinal contents collect and stagnate. Poor drainage leads to secondary infection and occasionally to deficiency syndromes. It typically occurs with a side-to-side anastomosis but may occur after a gastrectomy in which the terminal ileum rather than the jejunum is erroneously anastomosed to the stomach. Long afferent loops after a gastric resection and gastrojejunostomy may lead to major dilation of the afferent loop (afferent loop syndrome). In some cases, side-to-side small-intestine anastomosis is followed by marked dilation of the blind ends of the two segments.

Typical symptoms include indigestion, gas, cramps, and diarrhea. Antibiotic therapy is not useful. Surgical reconstruction may be needed.

Infective Lesions

Diseases that mimic surgical emergencies are common. Acute gastroenteritis with its typical acute onset, nausea, vomiting, and diarrhea can mimic a surgical abdomen. Unusual infections can also mimic a surgical abdomen. These include giardiasis, Yersinia infections, and acute amebiasis. Probably the most common and dangerous of all infections is salmonellosis. Patients treated with antibiotics and those receiving immunosuppressants are at particular risk of developing salmonellosis.

Organisms that produce toxins (eg, staphylococci, Vibrio cholerae, Campylobacter sp, Clostridium perfringens) can cause severe enteritis or colitis. One of the most common diseases that can cause a surgeon to be consulted is pseudomembranous enterocolitis from Clostridium difficile.