1. Usefulness of high resolution computed tomography scan in the detection and characterization of pulmonary infections in patients with febrile neutropenia

Objectives: To assess the usefulness of high resolution computed tomography scan in the detection and characterization of pulmonary infections in patients with febrile neutropenia.Material and Methods: Seventy five (75) patients with febrile neutropenia admitted in different ward of a tertiary care hospital were selected for the study. A detailed history regarding pulmonary symptoms and background illnesses was taken followed by detailed clinical examination and basic investigations like complete haemogram and chest X-ray (PAview). HRCT scan of thorax was done in each patient for detection of any pulmonary lesion and characterization of the lesion, if present. Final diagnosis was reached on the basis of sputum, blood, bronchoalveolar lavage or transbronchial biopsy examinations and/or clinical response to a particular antibiotic /antifungal agent.Results: Mean age of the patients was 14 to 71 years. Commonest symptoms were fever (100%) followed by dyspnoea (32%) and cough (24%). Chest X-ray could detect pulmonary abnormalities in 21(28%) cases and could characterize the lesion in 2(2.7%) cases only. HRCT thorax could detect pulmonary abnormalities in 69(92%) cases and could correctly characterize the lesions in 86% cases. Consolidation, ground glass opacity and nodules are predominant findings on HRCT in febrile neutropenic patients. Though considerable overlap existed, consolidation was commonly found in pyogenic infection, nodules with surrounding ground glass opacity in fungal infection and ground glass opacity in pneumocystis jiroveci infection. The sensitivity of HRCT in diagnosis of pyogenic, fungal, tuberculosis and pneumocystis jiroveci pneumonia was 83.33%, 92.8%, 78% and 88.89%, respectively. The specificity of HRCT in diagnosis of these infections was 88.5%, 86.26%, 94.72% and 81.12% respectively.Conclusion: HRCT can detect almost all types of infections in patients with febrile neutropenia with high sensitivity and specificity. Therapy can be started on the basis of HRCT findings even before the laboratory confirmation of infections in a significant number of cases. HRCT should be done in all febrile neutropenic patients to detect pulmonary focus of infection and to characterize the lesions for specific management.