Chest Multi-Detector Computed Tomography Findings among Patients with H1N1 Influenza A Infection: A Retrospective Study

Abstract

Introduction: The first cases of H1N1 Influenza A occurred in Mexico in 2009, thereafter the infection rapidly spread worldwide. Seasonal epidemics and unpredictable pandemics had been declared by the World Health Organisation (WHO), since then. Aim: To describe the Thoracic Multi-Detector Computed Tomography (MDCT) findings in moderate to severely ill, H1N1 patients during epidemic spread. Materials and Methods: A retrospective observational study was done in which evaluation of 155 hospitalised patients confirmed to have H1N1 Influenza A epidemic infection between October 2018-December 2018, through the radiologic and clinical aspects. About 56 moderate to severely ill patients, who failed to improve with through treatment, underwent thoracic cross-sectional MDCT and their scans available on picture archiving and communication system (PACS) were assessed and radiological findings were evaluated with respect to clinical condition. Descriptive statistics were used for representation of data. Results: About 56 moderate to severely ill H1N1 patients who underwent chest MDCT, consisted of 30 males and 26 females ranging in age from 20 to 86 years with median age of 55.19 years. Ground glass opacities was found in 34 (60.71%) patients, Consolidation in 33 (58.93%) patients, combined Ground glass pattern and Consolidation in 18 (32.14%) patients and Acinar nodules in 21 (37.50%) patients. Combined Peripheral & Central distribution of lesions was found in 47 (83.92%) patients and central lesions in 6 (10.71%) patients. The lesions were multifocal in 51 (91.07%) patients and diffuse in 25 (44.64 %) patients. Lesions seen in bilateral all lobes in 25 (44.6%) patients and unilateral in 7 (12.5%) patients. Small mediastinal Lymphnodes were detected in 42 (75%) patients, pleural effusion was associated in 18 (32.14%) patients and pericardial effusion in 4 (7.14%) patients. In nonvulnerable group, 53 (94.6%) patients showed full recovery as in those patients therapy was started earlier while in vulnerable group 3 (5.35%) died immediately after infection. Conclusion: Unilateral or bilateral ground-glass opacities may or may not be linked with focal or multifocal areas of consolidation in the peribronchovascular and subpleural distribution that resembled the appearance of organising pneumonia is the main finding which was observed.

Keywords

• h1n1 pneumonia
• swine flu
• swine-origin influenza