Chest Imaging Findings from a Tertiary Teaching Hospital in Andhra Pradesh, India in the Recent Epidemic of H1NI Viral Pneumonia

CHEST IMAGING FINDINGS FROM A TERITARY TEACHING HOSPITAL IN AP IN THE RECENT EPIDEMIC OF H1NI VIRAL PNEUMONIA Background: Influenza viruses are common and important pathogens causing seasonal epidemics and unpredictable pandemics. Mainly associated with influenza A virus (�swine� Flu or H1N1) Death toll due to swine flu during recent epidemic (2018-19) in India is nearly 400, according to the Union Health Ministry, while the number of those infected by it has crossed 12, 000. Still many infected and deaths are unrecorded or under reported. So far, 140 positive cases were reported in the State of Andhra Pradesh. Clinically, wide range of illness ranging from asymptomatic infection to acute respiratory distress syndrome (ARDS) complicated by multi-organ failure were documented. Vulnerable groups showed high risk for morbidity and mortality. Radiologically, also wide range of chest HRCT findings were described including patchy ground-glass opacities and air-space consolidations. Diffuse alveolar damage and ARDS were considered to be the end result. Aim: Aim of our study is to evaluate various patterns and imaging features associated with documented H1N1 infection on CT chest referred to our institute. The initial radiographs and Computed tomography (CT) scans obtained were reviewed regarding pattern, distribution and the lung zones involved. The patient case sheets were studied for any underlying co-morbidities. Methods: This study was conducted on 10 patients, who tested positive for H1NI virus from December 2018 till February 2019 admitted in our institute, GSL Medical College, Rajahmundry, Andhra Pradesh. The chest radiographs& CT findings of these patients were evaluated. Results: HRCT findings associated with H1N1 infection are variable and ranges from mild cases with patchy ground glass opacities (with or without crazy paving pattern) up to air space consolidations, alveolar haemorrhage, pleural effusions& ARDS. Manifestation of bronchiolitis obliterans was also detected including mucous plugging, mosaic attenuation with air trapping and bronchiectasis. Conclusion: CT picture of H1N1 chest infection is highly variable with a spectrum of findings ranging from focal patchy ground glass attenuation to consolidations, or adult respiratory distress syndrome (ARDS). Still, constellation of clinical data and HRCT findings especially in endemic areas can raise the suspicion of H1N1.