Radiological Findings in Patients with H1N1: A Report from the Referral Center of Northwest of Iran

Background: Influenza viruses are classified into three types of A, B, and C, with H1N1 being a member of the influenza A subtype. The majority of people infected with influenza, namely H1N1, exhibit self-limited, uncomplicated, and acute febrile respiratory symptoms, or are asymptomatic. However, severe disease and complications due to infection, including hospitalization and death may occur. One of the most prominent features of influenza infections are radiologic findings in chest X-rays, computed tomographic scan, and angiographies. Methods: In a descriptive-analytical study, all patients who were diagnosed with H1N1 at the Sina Educational-Medical Center of Tabriz University of Medical Sciences (Tabriz, Iran) from September 2015 to September 2016 were analyzed based on age, clinical presentation, and radiological findings. Results: A total of 53 cases, 30 females (57%) and 23 males (43%), were included in the study. The mean age was 48.45 ± 1.7. The most common clinical presentation was myalgia (92.5%). Chest X-ray (CXR) was done in all patients, 35 cases (66%) were found with bilateral abnormality, 11 cases (20.8%) without abnormality, and seven cases (13.2%) with unilateral abnormality. Chest computerized tomography (CT) scan was also done on all patients, 33 cases (62.2%) were found with bilateral abnormality, 17 cases (32%) without abnormality, and three cases (5.6%) with unilateral abnormality. CT angiography was done in eight patients; none of the patients showed any signs of pulmonary embolism. It was observed that CXR and CT-scan were both precise in studying radiological findings in H1N1. Conclusions: The majority of patients had revealed bilateral abnormality in radiographic findings, and unilateral involvement was less common; in addition, involvement in the superior lobes of the lungs were more common than the basal lobes. CXR and CT scans had no significant difference in diagnosing the disease.