Radiologic manifestations of patients with H1N1 infection

Purpose: Swine flu influenza is a very contagious respiratory infection and WHO has raised the alert level to phase 6 (pandemic). The aim of this study was to evaluate the chest X-ray and CT scan of patients with documented influenza A (H1N1) virus infection Material and methods: 31patients (16 men and 15 women), with H1N1infection confirmed by RT-PCR were included. 31 patients had available chest X-rays and of these 10 had CT scans. The initial radiography obtained from the patients was reviewed regarding pattern (consolidation, ground glass, nodules and reticulation), the distribution (focal, multifocal, and diffuse) and the lung zones involved. CT scans were also reviewed for the same abnormalities. The patient files were studied. LDH and CPK level was available for 22 and 24 patients respectively. Results: The mean age was 37.97±13.9 years. 17 (54.8%) patients had Co-existing condition (8 Respiratory, 5 cardiovascular, 2 Immunodeficiency, 2 Cancer, 4 others). 12 (38.7%) patients required ICU admission. 5 (16.1%) patients died.8 (25.8%) had normal initial radiographs. The most common radiographic abnormality was consolidation (12/31; 38.7%) in the peripheral region (11/31; 35.5%) followed by peribronchovascular (10/31; 32.3%) which was most commonly observed in the lower zone (left 61.3%; right 45.2%). The patients admitted to the ICU were more likely to have two or more lung zones involved (p =0.005). 11 (35.5%) patients had pleural thickening or effusion. Conclusion: In patients with the novel swine flu the most common radiographic abnormality observed in our center was consolidation in the lower lung zones. Patients admitted to ICU were more likely to have two or more lung zones involved.