Peritoneal tuberculosis is an uncommon site of extrapulmonary infection caused by Mycobacterium tuberculosis (TB). The risk is increased in patients with cirrhosis, HIV infection, diabetes mellitus, underlying malignancy, following treatment with anti-tumor necrosis factor (TNF) agents, and in patients undergoing continuous ambulatory peritoneal dialysis [1-5].
Infection occurs most commonly following reactivation of latent tuberculous foci in the peritoneum that were established from hematogenous spread from a primary lung focus . It can also occur via hematogenous spread from active pulmonary or miliary TB. Much less frequently, the organisms enter the peritoneal cavity transmurally from an infected small intestine or contiguously from tuberculous salpingitis .
As the disease progresses, the visceral and parietal peritoneum become increasingly studded with tubercles. Ascites develops secondary to "exudation" of proteinaceous fluid from the tubercles, similar to the mechanism leading to ascites in patients with peritoneal carcinomatosis. More than 90 percent of patients with TB peritonitis have ascites at the time of presentation, while the remainder present with a more advanced "dry" phase, representing a fibroadhesive form of the disease [7,8].
Approximately 70 percent of patients have symptoms for more than four months before the diagnosis is established [9,10]. This is due in part to the insidious onset of the disease and because the diagnosis is frequently unsuspected. In patients with renal failure, symptoms and signs typically develop within the first year of beginning continuous ambulatory peritoneal dialysis (CAPD) and are usually indistinguishable from bacterial peritonitis. TB peritonitis should be added to the differential diagnosis of any patient presenting with several weeks of abdominal pain, fever, and weight loss.
One of the largest contemporary series included 60 patients who were identified during a 12-year period at a center in Hong Kong . The mean age at presentation was 55 with an approximately equal gender distribution. Risk factors (in descending order of frequency) included cirrhosis, CAPD, diabetes mellitus, underlying malignancy, use of systemic corticosteroids, and AIDS. However, 20 percent of patients had no risk factor.