Impact of CD4 Count on sputum smear for AFB in HIV-TB Co infection

Abstract

Background: Human immunodeficiency virus (HIV) infection is a major threat in the world population and in the control of tuberculosis in developing countries. HIV-TB co infected patients with CD4 counts above 200 cells/cu µl, are likely to have typical symptoms and most of the sputum shows positive for acid fast bacilli (AFB). Patient withCD4 count less than 200 are with high risk of getting (Tuberculosis) TB, but diagnosis is difficult as there is more chances of sputum becoming negative, which requires sputum culture for diagnosis of (TB). Although sputum smear negativity is high in most cases of dual infection, particularly in patients with low immunity, it is an essential component in the diagnosis of tuberculosis in countries like India. Methodology: A cross sectional study of 50 HIV-TB patients admitted to tertiary care hospital were studied for correlation between CD4 count and sputum smear results. Results: 50 HIV-TB patients studied for a period of 1 year. Majority were in the age group of 30-40 years 20 (78%). In the study 29 (58%) were males and 21(42%) were females. The common presentations were cough 48 (96%), fever 44 (88%), weight loss 42(84%) and diarrhoea 25(50%). Mean CD4 count being 146.6±88. Most patients had CD4 count < 200 cells/cu µl. Mean CD4 count in sputum positive TB was 254.8±77.3 and in sputum negative TB was 97.2±33.8. Conclusion: Patients with CD4 count > 200cells/cuµl are likely to have sputum positive pulmonary TB and typical presentations. Patients with CD4count < 200cells/cuµl are more of sputum negative pulmonary TB with atypical presentations which poses diagnostic difficulty and needs newer diagnostic tests. Key words: HIV-TB co infected patients, CD4 count, Sputum for AFB