Bypass enteropathy. Intestinal and systemic manifestations following small-bowel bypass.

Many manifestations following jejunoileal bypass are due to chronic inflammation of the excluded bowel rather than short bowel malabsorption. Diarrhea, abdominal distention, and gas-fluid levels were common diagnostic features of "bypass enteropathy." Exploration showed the bypassed bowel to be dilated, with serosal inflammation and pneumatosis cystoides intestinalis. The bypassed loops contained a fecal flora and the mucosa demonstrated nonspecific chronic inflammatory changes. Exudative protein losses were noted. Systemic complications of bypass enteropathy were similar to other inflammatory diseases of the bowel. Improvement following treatment with metronidazole or after dismantling of the bypass suggested that bacterial byproducts originating in the excluded bowel were causally related.