Faculty Bibliography

OBJECTIVE: To evaluate the sensitivity of acid-fast sputum smears in the diagnosis of pulmonary Mycobacterium tuberculosis (MTB). DESIGN: Retrospective chart and radiographic film review. SETTING: Department of Veterans Affairs Medical Center in New York City. PATIENTS: All patients with positive sputum cultures for MTB during 1989 to 1991, including 100 with HIV, and 76 without HIV infection. PARAMETERS: The likelihood of a positive acid-fast sputum smear, related to chest radiograph findings, CD4 cell counts, drug sensitivity, and the presence of disseminated disease. RESULTS: Overall, 60 percent of patients with HIV had positive acid-fast smears, compared with 57 percent of non-HIV-infected patients. A relative absence of cavitary infiltrates did not substantially reduce the frequency of acid-fast smears in patients with and without HIV. Patients with HIV and CD4 count < 50, 50 to 200, and > 200 had positive acid-fast smear rates of 58 percent, 60 percent, and 56 percent, respectively; HIV-infected patients with drug-resistant organisms had 65 percent positive smears. Smear positivity was 96 percent in patients with HIV infection and disseminated MTB, CONCLUSIONS: Positive acid-fast sputum smears in culture-proven MTB occur with similar frequency in patients with and without HIV. The absence of cavitary disease did not significantly reduce the frequency of positive acid-fast smears. For patients with HIV, the likelihood of a positive smear was also independent of CD4 cell counts and drug resistance. Patients with HIV and disseminated MTB had positive sputum smears in nearly all cases.

Human immunodeficiency virus infection changes the clinical presentation of tuberculosis infection with atypical radiographs and more common extra-pulmonary involvement. We retrospectively studied pleural tuberculosis in HIV-positive patients over a 5-year period. We identified 70 patients with pleural tuberculosis by positive Mycobacterium tuberculosis cultures of pleural fluid and/or pleural tissue, including 43 HIV-positive and 27 HIV-negative patients. The HIV-positive patients were significantly younger (mean age, 38 +/- 1 years in HIV-positive vs 52 +/- 3 years in HIV-negative patients, p < 0.05). There were more intravenous drug abusers in the HIV-positive group (74 vs 30 percent, p < 0.01). The HIV-positive group had significantly fewer positive tuberculin skin tests (41 percent vs 76 percent, p < 0.03). Both groups had similar pleural fluid cellularity and pleural biopsy histologic conditions, but the HIV-positive patients demonstrated significantly more acid-fast bacteria identifiable in pleural tissue (69 percent vs 21 percent, p < 0.01), and a higher incidence of positive M tuberculosis cultures of sputum (53 percent vs 23 percent, p = 0.02). Pleural tuberculosis in HIV-positive patients presented more often as a manifestation of a greater burden of microorganisms and impaired host response

Large volume paracentesis (LVP) is a safe, rapid, and effective treatment of ascites in cirrhotic patients. We investigated the effects of a 5-L aspiration of ascites on pulmonary function parameters in eight hemodynamically stable patients with cirrhosis and tense ascites. None had known lung disease or abnormal chest roentgenograms. At baseline, mean lung volumes, diffusing capacity, and arterial pO2 were all reduced from normal predicted values. Airflow, however, when related to lung volume, was normal. Post-LVP, lung volumes increased significantly; the mean expiratory reserve volume showed the greatest percent increase (105%) and correlated with the increases in the vital capacity, functional residual capacity, and total lung capacity. Airflow, the mean diffusing capacity, and arterial oxygenation were not significantly changed after LVP. We conclude that LVP significantly increases indices of lung volume but does not significantly alter parameters of airflow or gas exchange.

An 81-year-old man being treated with weekly low dose methotrexate (MTX) for psoriasis was admitted with a 2-month history of cough, shortness of breath and 7% eosinophilia in the peripheral blood. Chest roentgenogram revealed bilateral alveolar and interstitial infiltrates. Although the clinical presentation suggested MTX pneumonitis, a transbronchial lung biopsy established a diagnosis of pulmonary cryptococcosis. Pulmonary cryptococcosis should be included in the list of infectious processes that can mimic MTX pneumonitis

Gallium-67 localizes to the cellular fraction of bronchoalveolar lavage (BAL) fluid in patients with sarcoidosis, idiopathic pulmonary fibrosis, as well as normal subjects. To further study 67Ga disposition in BAL fluid, 11 patients with Pneumocystis carinii pneumonia (PCP) and 8 patients with a variety of other lung diseases, underwent BAL 24 hr after 67Ga injection. Compared to the non-PCP patients, PCP patients had high uptake gallium scans at 24 and 72 hr, and showed significantly increased radioactivity in both unfractionated lavage and in the acellular, supernatant fraction of BAL. The mean ratio of total supernatant/cell pellet radioactivity was also higher in patients with PCP (1.23 +/- 0.27 versus 0.24 +/- 0.05, p less than 0.01). Supernatant radioactivity correlated with the presence of neutrophil alveolitis, but not with BAL transferrin concentrations. We conclude that neutrophil alveolitis in PCP promotes 67Ga accumulation in the acellular fraction of BAL fluid. However, the high uptake 67Ga scans observed in PCP patients without neutrophil alveolitis suggest that the mechanism of pulmonary uptake of 67Ga is not fully elucidated by BAL fluid analysis alone

Spontaneous pneumothorax is a known complication of Pneumocystis carinii pneumonia (PCP) in patients with acquired immunodeficiency syndrome. From a series of 61 patients with PCP, we identified two cases, not associated with aerosolized pentamidine, that presented with spontaneous pneumothorax and cystic changes seen on chest radiographs. Bronchoalveolar lavage cell findings were remarkable for very elevated neutrophil counts in both cases, suggesting a possible inflammatory cause for the observed cystic changes.