HIV infected patients have an increased risk of developing tuberculosis (TB) due to a loss of cell mediated immunity. along with a quantitative decline in circulating CD4+ lymphocytes, there is also a qualitative change in function. As a result, at a specific CD4+ count, tuberculosis occurs sooner than other opportunistic infections. Our aim was to investigate the relationship between CD4+ counts and manifestations of tuberculosis in HIV patients.
Retrospective chart review was done on patients admitted to the hospital, or referred to our specialty clinic. Data abstracted included patients demographics, medical history, clinical presentation, CD4+ cell counts, sputum for acid-fast bacilli (AFB), tuberculin test (PPD), and radiology findings.
Forty one HIV positive patients infected with tuberculosis were included in the study. The mean was 31, with 73% being 20 - 40 years old. 34 (82%) were male. 27 (66%) were married, with 95% heterosexual transmission. Sputum for AFB was negative in 90%. PPD was negative in 35 (85%) of patients. Chest roentgenograms were reported per radiology and were classified as typical (cavitary lesions or apical infiltrates) or atypical presentations. 26 (63%) had atypical findings. CD4+ cell counts were less than 200 cell/micro liter in 56% of patients. 18 patients were noted to have isolated pulmonary TB. Isolated pulmonary TB was seen at mean CD4+ cell count of 253, with extrapulmonary TB seen at a mean count of 212.CONCLUSIONS: The incidence of TB increases as CD4+ cell counts fall. Clinically evident TB appears at CD4 counts below 500. Maximum incidence occurs when the count is below 200. Isolated pulmonary TB occured at CD4+ counts >300. Dissemination with extra-pulmonary sites of infection occurred when CD4+ counts were <100.
Pulmonary TB in HIV patients is predominantly atypical in its presentation. CD4 cell counts are indicative of dissemination of infection with isolated pulmonary tuberculosis occuring at higher levels and extrapulmonary TB seen usually when the counts are below 100 cells/microliter.
N.I. Gupta, None.