In 1994, 16% of newly reported cases of Mycobacterium tuberculosis involved extrapulmonary sites. Often, these cases represent a diagnostic challenge. Many sites are not easily accessible and require invasive procedures for diagnosis.
A 27 year old Mexican male presented to the ED with progressive shortness of breath, fever, night sweats, and a 10 pound weight loss over 1 month. He also had abdominal and chest pain of 5 months duration. Oral temperature was 103, other vitals were unremarkable. Labs were remarkable for anemia and elevated liver function tests. A chest roentgenogram revealed a small left pleural effusion and mediastinal collection. He was placed in respiratory isolation. Sputa were negative for AFB x 3. A body CT revealed multiple cystic collections along the left pleura from the apex to the diaphragm, anterior mediastinum, abdomen, and pelvis. Empiric treatment was started for echinococcus and bacterial superinfection with albendazole, ciprofloxacin, and metronizadole. Serum echinococcus Ab was negative. A 6cm x 6cm parahepatic cyst was drained by CVIR. The cultures grew Streptococcus intermedius/milleri. Ampicillin-sulbactam was started, but fever persisted. Endocarditis was suspect, but there was no evidence of vegetation on echocardiogram. An exploratory laporoscopy was then required which revealed liver cystic structures, intraabdominal adhesions, and plaques along all peritoneal surfaces. The largest of the cystic structures was excised and sent for frozen section. A necrotizing granuloma was identified. AFB smears were negative. Because of a high index of suspicion, treatment with isoniazid, rifampin, ethambutol, pyrazinamide, and B6 was started. CVIR drained the pleural fluid, also AFB smear negative. Eventually, AFB cultures of the peritoneal biopsy and pleural fluid grew Mycobacterium tuberculosis. An immunocompromised state was suspect. HIV test was negative. After two weeks of treatment, the patient was discharged on antituberculosis treatment and amoxicillin-clavulanate.DISCUSSION: Before the recognition of HIV, more than 80% of all cases of M. tuberculosis were limited to the lungs. Up to 2/3 of HIV infected patients with tuberculosis have both pulmonary and extrapulmonary or extrapulmonary tuberculosis alone. Extrapulmonary tuberculosis presents more of a diagnostic challenge than pulmonary tuberculosis, especially in those that do not carry a diagnosis of HIV. The presenting symptoms and signs are nonspecific: fever, weight loss, night sweats, anorexia, and weakness. Those patients with the highest risk include: HIV infected, foreign born, household contacts of the infected, low income populations, homeless, alcoholics, injection drug users, residents of nursing homes or prisons, and those with medical conditions that predispose to immunosuppression. The patients that offer no medical history may go undiagnosed. In adults, infections may be due to new infection, reactivation of previously latent infection, or very rarely reinfection. Common sites of reactivation are the apices of the lungs, vertebrae, and kidneys. In order of frequency, the extrapulmonary sites commonly involved are the lymph nodes, pleura, bones, joints, meninges, and peritoneum. These sites require invasive procedures for diagnosis. The specimens should be sent for AFB smear, mycobacterial culture, and histology. The main histologic finding is the necrotizing granuloma. M. tuberculosis is slow growing and may require 4 to 8 weeks for growth, as in this case. An intermediate strength PPD test is a helpful adjunct for diagnosing exposure to or infection with M. tuberculosis. However, it may be falsely negative in those with active disease and overwhelming infection. When considering extrapulmonary tuberculosis, clinicians must maintain a high index of suspicion to pursue the diagnosis.
Extrapulmonary findings and persistent fever should prompt a continued search for M. tuberculosis,especially in a patient coming from an area where M.tuberculosis is prevalent.
E.U. Bollenbacher, None.