Methods for diagnosing tuberculosis among in-patients in eastern Africa whose sputum smears are negative

SETTING

Two University hospitals in Eastern African capital cities where large prospective studies had been carried out on hospitalized patients to determine the cause of their respiratory diseases.

OBJECTIVE

To identify features that differentiated between tuberculosis (TB) and non-tuberculous respiratory disease (non-TB) in hospitalized patients from Bujumbura, Burundi (n = 111) and Dar es Salaam, Tanzania (n = 71) whose sputum smears were negative on microscopic examination for acid-fast bacilli (AFB).

DESIGN

Review of clinical findings, radiologic abnormalities, and laboratory test results from 182 patients, first by univariate and then by multivariate (stepwise logistic regression) analysis to assess the contribution of each factor to the final diagnosis.

RESULTS

Of the 182 patients with two or more negative AFB smears, 41 had TB and 141 had non-TB. Stepwise regression analysis revealed four easily ascertained symptoms were associated with TB: 1) cough > 21 days; 2) chest pain > 15 days; 3) absence of expectoration; and 4) absence of shortness of breath. Any two of the four diagnosed TB with 85% sensitivity and 67% specificity; any three of the four with 49% sensitivity and 86% specificity. Multivariate analysis showed that adding lymphadenopathy and hematocrit < 30% improved discrimination.

CONCLUSION

This methodological approach provides a means for diagnosing TB among all AFB smear-negative hospitalized patients. In this setting, simple clinical symptoms alone are helpful. Similar studies are needed to develop a system for out-patient TB suspects.

Pulmonary complications of HIV infection in Dar es Salaam, Tanzania. Role of bronchoscopy and bronchoalveolar lavage

To determine the pulmonary complications in HIV-1-infected patients in Dar es Salaam, Tanzania, and to evaluate the diagnostic utility of bronchoscopy and bronchoalveolar lavage, we carried out a prospective study of 237 patients with acute respiratory disease who were hospitalized at Muhimbili Medical Center (MMC). Diagnoses were made using well-defined criteria. Of the total, 127 (54%) were HIV-1-seropositive and 110 (46%) were seronegative. Tuberculosis was the most common diagnosis occurring in 95 (75%) HIV-1-seropositive and 87 (79%) seronegative patients. Bacterial pneumonia was the next most common diagnosis occurring in 18 (14%) HIV-1-seropositive and 17 (15%) seronegative patients. Pneumocystis carinii pneumonia was diagnosed in one and Kaposi's sarcoma was seen in only two HIV-1-seropositive patients. Bronchoscopy with bronchoalveolar lavage was the sole source of a diagnosis in nine (8%) seropositive and six (5%) seronegative patients. We conclude that the HIV seroprevalence rate among patients hospitalized for acute respiratory disease at MMC is extremely high. Tuberculosis was the most common cause of pulmonary disease, regardless of HIV serostatus, and other HIV-associated opportunistic pulmonary infections were unusual. Bronchoscopy with bronchoalveolar lavage added little to the diagnosis and thus should not be high-priority procedures for the routine workup in resource-poor areas where tuberculosis is endemic.

Radiographic abnormalities in tuberculosis and risk of coexisting human immunodeficiency virus infection. Results from Dar-es-Salaam, Tanzania, and scoring system

First, we evaluated the age profile and chest radiographic abnormalities in 146 patients from Dar-es-Salaam, Tanzania, with new-onset intrathoracic tuberculosis (pulmonary, pleural, or hilar/mediastinal adenopathy), to identify features that were associated with human immunodeficiency virus (HIV) seropositivity or seronegativity; then, we combined these data with those from a companion investigation in Burundi to develop a simple scoring system to predict HIV serologic status. Using agreed-upon criteria and simplified reporting forms, initial chest radiographs were reviewed by three readers, first independently and then at a consensus conference. Of the 146 patients, 80 (55%) were HIV seropositive and 66 were seronegative. More seropositive than seronegative subjects were 31 to 40 yr old (p = 0.03). Because the radiographic characteristics of the two serologic groups were similar in Tanzania and Burundi, we combined the data for stepwise logistic regression that revealed four highly significant variables: age, small lesions, location, and lymphadenopathy. From these, we obtained an equation to calculate the probability that a given tuberculosis patients was HIV seropositive and then we derived a scoring system that in its simplest form (threshold) predicted serologic status correctly in 68.1% of patients; a graded scale was even more accurate in the high (89.1%) and low (82.6%) ranges. This scoring system should be useful when serologic testing is unavailable or refused.

Oral candidiasis and hairy leukoplakia correlate with HIV infection in Tanzania

We report a detailed study on oral lesions and their association with the WHO revised provisional case definition of AIDS as well as serologic signs of HIV infection among 186 patients in Dar Es Salaam, Tanzania. The patient material consisted of 39 hospitalized suspected AIDS patients, 44 medical nonsuspected patients, 53 dental outpatients, and 50 patients with sexually transmitted diseases. The male:female ratio was 2.1:1 on average. Oral examination was done without knowledge of the HIV status of the patients. Among 39 suspected AIDS patients 97% had WHO AIDS criteria and 90% were seropositive for HIV. Among the 147 patients not suspected of having AIDS 18 (12%) had AIDS criteria and 15% had serologic evidence of HIV infection. The presence of WHO AIDS criteria correlated significantly with the presence of HIV antibodies, but not with HIV antigen. Oral lesions were found in 54% of those with AIDS criteria and 52% of HIV-infected patients, as compared to 3% and 6% of the patients without AIDS criteria and HIV infection, respectively (p less than 0.01). Among patients with AIDS atrophic candidiasis occurred in 21%, pseudomembranous candidiasis in 23%, hairy leukoplakia in 36%, herpetic stomatitis in 2%, Kaposi's sarcoma in 4%, and nonspecific ulcer in 4%. The presence of oral lesions had a high predictive value for presence of AIDS criteria as well as for presence of HIV infection in this hospital setting. All patients should have a thorough oral examination and the presence of the aforementioned oral lesions should lead to testing for HIV infection.