Lung infections in HIV-infected children: imaging pattern recognition and its correlation with CD4 counts

Children with human immunodeficiency virus (HIV) infection frequently present with opportunistic infections of the lung that may be associated with high mortality rate. There is no study, to the best of our knowledge, correlating specific radiographic patterns of chest infections with CD4 levels of immunity in HIV-infected children of Indian subcontinent (where prevalence of respiratory tuberculosis is very high). To study the radiological patterns of chest infections in HIV-infected children, and to correlate these radiological findings with CD4 cell count and final diagnosis. Forty-five HIV-infected children (1–18 years of age) with suspected chest infections were included in the study. The baseline and the most recent CD4 counts were recorded for each patient. Chest X-ray (CXR) was obtained in all the patients, and multi-detector computed tomography (MDCT) chest was done in 27 patients having clinical suspicion of infection with normal or equivocal findings on CXR. Chest radiographs and MDCT chest were analyzed for different radiological patterns of chest infections. Imaging findings were correlated with CD4 count range for disease spectrum. The final etiopathological diagnosis was achieved in combination with clinico-radiological findings, laboratory data, cytohistopathology and follow-up imaging. Out of 45 children confirmed to be HIV-infected, 27 (60%) had bacterial infection, 14 (31.11%) had tuberculosis, and four (8.89%) had fungal infection. Consolidation on CXR/CT strongly suggested bacterial etiology (P < 0.05). Mediastinal/hilar lymphadenopathy (with or without necrosis) strongly suggested tubercular etiology (P value < 0.05). Diffuse GGO/haziness on CXR/CT strongly suggested fungal etiology (P value < 0.05). On correlation with CD4 count (cells/mm3), the bacterial infections occurred at early stages of HIV infection when immune status was relatively preserved, and most of the patients with tubercular infection had moderate immunosuppression. On the other hand, all patients of fungal infection showed severe immunosuppression. A wide spectrum of pulmonary disease encountered in HIV-infected children warrants an integrated approach of image interpretation. Familiarity with the imaging patterns, combined with relevant clinical/laboratory details, may greatly help to improve the diagnostic confidence and to reach to a more meaningful differential diagnosis.