H1N1 viral pneumonia: Spectrum of chest HRCT findings

Abstract

Influenza viruses are common and important pathogens affecting human. Seasonal epidemics and unpredictable pandemics associated with influenza A (“swine” influenza or H1N1) virus had been declared by the World Health Organization (WHO), last one on June 11, 2009.Clinically, wide range of illness was described ranging from asymptomatic infection to acute respiratory distress syndrome (ARDS) complicated by multi-organ failure. Vulnerable groups showed high risk for morbidity and mortality.Radiologically, also wide range of chest HRCT findings were described including sub-centimeter air-space nodules, patchy ground-glass opacities and air-space consolidations. Diffuse alveolar damage (DAD) and ARDS were considered to be the end result.Aim of study was to evaluate different patterns and imaging findings associated with H1N1 lung infection using MSCT of the chest. Aim of the workThe aim of study was to evaluate different patterns and imaging findings associated with H1N1 lung infection using MSCT of the chest. MethodsThis study was conducted on 50 patients from September 2013 till February 2016. All patients were examined by multi-detector computed tomography (MDCT). ResultsHRCT findings associated with H1N1 chest infection can overlap and range from mild cases with patchy ground glass opacities (with or without crazy paving pattern) up to air space consolidations, alveolar hemorrhage, diffuse alveolar damage (DAD) and ARDS. Manifestation of bronchiolitis obliterans was also detected including mucous plugging, mosaic attenuation with mixed air trapping and ground glass opacities (head cheese pattern) and bronchiectasis. ConclusionMDCT picture of H1N1 chest infection is highly variable with a spectrum of HRCT findings ranging from focal patchy ground glass attenuation to diffuse alveolar damage (DAD) or adult respiratory distress syndrome (ARDS). Still, constellation of clinical data and HRCT findings especially in endemic areas can raise the suspicion of H1N1.