Tuberculosis (TB) in human immunodeficiency virus (HIV) immunosuppressed patients is characterized by extra-pulmonary disease in as many of 70% of them. If intestinal or lymph node involvement occurs, the differential diagnosis between an acute abdomen and other non surgical condition may be a challenging problem. Double infected patients (TB and acquired immunodeficiency syndrome-AIDS) should be considered when abdominal pain, anemia , fever, weight loss and abdominal lymph node enlargement are present. Bacteriology of body fluids, abdominal ultrasound (US) and computed tomography scans (CT) combined with guided needle aspiration biopsies, barium examination, colonoscopy and laparoscopy, can not only elucidate the diagnosis but also be helpful in assessing an appropriated management. Thus a systematic evaluation often yields an etiology and a correct therapeutic indication reducing the high mortality rate
KEY WORDS: Acquired Immunodeficiency Syndrome, Human Immunodeficiency Virus, Tuberculosis, Surgery, Laparotomy, AIDS, HIV
In Brazil 500.000 of sexually active urban people are thought to be infected with HIV. There is a prevalence of HIV-1 infection although association with a different type retrovirus HTLV-1, has been recently reported.
The World Health Organization estimates that nearly 45% of adults in developing countries are infected with "mycobacterium tuberculosis". The rising incidence of TB in endemic areas is a consequence of profound immune defect produced by the HIV that causes impairment of B cell,citotoxic T cell, natural killer cell and macrophage function. That defect leads to reactivation of a mycobacterial latent focus, generally localized in pulmonary lymph nodal and intestinal sites. Granuloma formation with presence of a solid or semisolid necrotic material referred as caseous, is pathognomonic.
In our experience tuberculosis is more common among white homosexual and bisexual men who did not use drugs. These results were quite similar of those reported in American- born AIDS population from San Francisco. Studies that have linked TB to AIDS have shown high prevalence in persons who are 24 to 54 years old.
The three major routes of intra-abdominal tuberculosis are hematogenous dissemination, swallowed organisms from pulmonary regions, and mycobacterium tuberculosis penetration through the intestinal layers coming from granulomas or lymphoid follicles as Peyer patches. There is an increasing number of extrapulmonary tuberculosis related not only to the degree of the patient's immunosuppression by HIV, but also to the extent of the diagnostic evaluation of extrapulmonary sites. The widespread of intra-abdominal tuberculosis may result in peritonitis. Classically there are two main types of tuberculous peritonitis. An exsudative form with ascites, and a fibrotic type with little or no ascites and predominant intraperitonial adhesions.
Patients who have concurrently extra-pulmonary and pulmonary TB complain of coughing, sputum production and pleuritic chest pain. Clinical features in patients with intra- abdominal tuberculosis and AIDS generally include weight loss, chronic abdominal pain, anemia, fever, and occasionally diarrhea. This last sign may not only be caused by lymphatic ileocecal obstruction that leads to a proximal bacterial overgrowth and to a delay in chylomicron removal , but also by AIDS enteropathy. Despite the lymphadenopathy, a palpable mass is unusual in TB patients when there is no accompanying intestinal tuberculosis especially in the ileocecal region. Loss of body weight (defined herein as at least a 10 per cent decrease form baseline) may result from malabsorption or from a variant stagnant loop syndrome. Anorexia and gastrointestinal opportunistic infections may be cofactors contributing to catabolic weight loss. Presentation at the emergency room is primarily for acute abdominal pain. Rebound tenderness suggests peritoneal irritation. In such instances abdominal muscles rigidity would be apparent. Oral or cutaneous lesions , hepatomegaly and asthenia have also been described in the clinical setting of HIV infection. In addition, hepatomegaly can be associated with diffuse right upper quadrant pain resembling cholecystitis.
Once presumptive diagnosis of intra-abdominal tuberculosis is established in patients with AIDS, laboratory testing provides essential informations. Standard procedures capable of detecting the presence of HIV or serologic response to it, must be done. A positive tuberculin skin test is noteworthy especially in HIV infected patients who have never had close contact with a population in which tuberculous infection is highly prevalent. Preoperative blood cell count shows nearly always low hematocrit values. Most of the times neutrophilia is evident. It has been reported that combination of preoperative hypoalbuminemia and opportunistic infection is correlated with a decrease in the survival rate.
Among HIV immunosuppressed patients classic tuberculous signs on chest radiography are uncommon and findings are often atypical. Abdominal X-ray films findings are usually inconclusive. Therefore free peritoneal air or multiple gas fluid levels with dilataded intestinal loop may confirm a surgical diagnosis. Ultrasound is an useful screening technique, however CT is superior in evaluating retroperitoneal and mesenteric disorders. Guided percutaneous aspiration or biopsies usually provide appropriate samples for establishing the etiologic diagnosis. So if the plain films are normal and acute abdominal pain is present, US and CT should be used as soon as possible. Full colonoscopy with visualization of the terminal ileum and biopsies from small bowel lesions may be associated with barium radiography in order to distinguish an intestinal involvement.
The list of illnesses that could be considered in the differential diagnosis of intestinal tuberculosis in AIDS patients includes Crohn's disease, malignant neoplasm, sarcoidosis, blastomycosis and actinomycosis . Concerning to a retroperitonial mass, not only sarcomas and lymphomas should be suspected, but also lymphadenitis.
Clinical treatment of tuberculosis in HIV infected patients with BK comprehends both antituberculous and antiviral drugs. Several therapeutic regimens are highly effective.
Elective procedures can be performed with minimal risk when properly indicated.
Otherwise emergency abdominal intervention in acutely ill patients with AIDS has been discouraging with morbidity rates approaching 100% and mortality rates of 70%. There are few literature data concerning about comparative reports of surgery results, in AIDS patients with intra-abdominal tuberculosis.There is a significant increased incidence of non-Hodgkin's lymphoma in patients with HIV infection. When intra-abdominal mass is suspected and mesenteric or retroperitoneal lymphadenopathy is diagnosed, it's advisable attempting to establish the etiology. Surgeons must be prepared to recognize this clinical tuberculosis syndrome associated with AIDS, specifically when patients are in stable conditions and without signs of intestinal perforation, obstruction, incontrolable bleeding and intra-abdominal sepsis. Thus a meticulous diagnostic approach must be followed in order to avoid unnecessary laparotomy. There are no simple objective criteria that can reliably select patients who will require laparotomy (emergency or elective) as opposed to those that will present good results to nonoperative treatment. On the bases of this study the authors recommend a general approach aiming an adequate management (Fig. 1).
At laparotomy, an experienced surgeon can raise the suspicion of tuberculosis considering the gross appearance of the gut. Tuberculous lesions of the bowel wall appear like an inflammatory mass. The serosal surface is covered with multiple tubercles. There are wall thickening and mesenteric lymph node enlargement which upon sectioning reveals caseous necrosis. Gastrointestinal massive bleeding is unusual in these patients. The early and most frequent complication after major intestinal operations is anastomotic dehiscence followed by peritonitis and also wound and intra-abdominal abscesses. All of them contribute to sepsis development. Acidosis, hypotension, respiratory failure and coma are clinical consequences contributing to death. Mortality is increased when AIDS is present, rather than just HIV infection.
Once AIDS has been diagnosed, approximately 40% of patients die within four months. In conclusion the goal of laparotomy in these circumstances should be the solution of a specific surgical problem rather than the creation of another one. Thus successful management of intra-abdominal tuberculosis in AIDS patients demands a thorough knowledge of the natural history of this unusual syndrome that simulates an acute abdomen.
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