Radiograph patterns of pulmonary tuberculosis in relation to CD4 levels in HIV-positive adults at Moi teaching and referral hospital

Abstract

Background: Pulmonary tuberculosis (PTB) is the commonest clinical presentation of tuberculosis. It has been declared a global public health emergency by WHO. It’s the commonest opportunistic infection and cause of death in people infected with HIV. Chest radiography is useful in diagnosis and assessing response to therapy. Chest radiograph features in people with PTB and HIV co infection are atypical and are affected by CD4 levels. Some recent literature suggests that some of the features are changing in different geographic locations. Objective: To determine chest radiograph features in relation to CD4 counts in adult patients with smear positive PTB and HIV co infection at MTRH Study design: A cross sectional study Setting: Chest clinic at MTRH, Kenya Subjects: Newly diagnosed smear positive, HIV positive patients aged 16 years and above Methods: 115 patients (using Fischer’s formula with finite population adjustment) were studied between October 2011 and November 2012. Data on demographics, clinical presentation, physical examination findings, CD4 counts and chest radiograph findings were collected and analysed using STATA version 12. Descriptive statistics were carried out for continuous variables using mean, median, standard deviation and inter-quartile range. Frequency tables were generated for categorical variables. The chi square test and Fishers’ exact test were used to test for any associations. A p-value < 0.05 was considered statistically significant. Results: 55% of those studied were male. The mean age was 36 years. 58% of the patients had CD4 counts below 200cells/mm 3 , 61% of whom were male. The most common radiograph patterns, in order of frequency, were pulmonary infiltrates (60%), cavitations (25.2%), normal (23.5%), interstitial pattern (19.1%), consolidation (13.9%), pleural effusion (13%), scarring (9.6%), miliary pattern (9.6%) and hilar lymphadenopathy (1.7%). Normal radiographs and miliary pattern showed a significant association with CD4 counts below 200cell/mm 3 (p=0.001 and 0.014 respectively). Consolidation, scarring and pleural effusion had a significant association with CD4 counts above 350cells/mm 3 (p=0.001, 0.024 and 0.006 respectively). The other radiograph patterns showed no significant association with CD4 level. Conclusion: Pulmonary infiltrates is the most common radiographic pattern in patients with smear positive PTB/HIV co infection. Normal radiographs and miliary pattern are significantly associated with CD4 counts below 200cells/mm 3 , while consolidation, scarring and pleural effusion have a significant association with CD4 counts above 350cells/mm 3 .