Radiographic presentation of pulmonary tuberculosis in severely immunosuppressed HIV-seropositive patients

Although the presence of typical postprimary or "reactivation" pattern tuberculosis (TB) on chest radiograph (CXR) strongly suggests TB infection in adults, the sensitivity of this finding, particularly in severely immunosuppressed human immunodeficiency virus (HIV) patients, is unclear. To investigate this issue, HIV status, CD4 counts, and CXR findings of all adult patients with culture-proven TB admitted to a tertiary-care hospital over a 2-year period were retrospectively studied. CXRs were classified as typical for postprimary TB if they showed upper lobe opacities with or without cavitation. No attempt was made to correlate the actual clinical phase of TB infection (primary versus postprimary) with CXR patterns, largely because differentiating primary from postprimary TB in HIV patients is difficult due to high anergy rates and inability to skin-test-convert. Of 46 patients who had chest radiographs and medical records documenting HIV status available for review, 23 were HIV-seropositive and 23 were HIV-seronegative. Of 22 HIV-seropositive patients whose CD4 counts were available, 18 (82%) had CD4 counts of < 200 cells/microL. Only 2 of these 18 (11%) had CXRs showing a typical postprimary TB pattern, whereas all 4 (100%) patients with CD4 counts of > 200 cells/microL and 18 of 23 (78%) non-HIV patients had CXRs typical for postprimary TB (P < .005). It was concluded that HIV-seropositive patients with TB and CD4 counts of < 200 cells/microL frequently present with chest radiographs atypical for postprimary TB, including normal CXRs. Typical postprimary TB CXR findings are not sensitive for diagnosing pulmonary TB in this population.