A clinical account of hospitalized 2009 pandemic influenza A (H1N1) cases

To determine the clinical characteristics in adults with confirmed pandemic influenza A (H1N1) infection 2009. A case series. The study was carried out at the Department of Pulmonology and Critical Care, Military Hospital, Rawalpindi, from 1st December 2009 to 30th May 2010. Thirty six adults with confirmed 2009 pandemic H1N1 infection by reverse transcriptase polymerase chain reaction (RT-PCR) were included in the study. All patients were followed in-hospital and clinical features, laboratory and radiological investigations and management data was collected on a pre-designed patient data collection form. Mean age was 34.24±13.92 years with 61.1% females. Seventeen (47.2%) had at least one risk factor for complications with 2009 H1N1 infection; namely obesity in 19.4%, pregnancy in 8.3%, COPD in 5.6%, cardiac failure in 5.6%, chronic liver disease in 5.6%, Diabetes mellitus in 5.6%, immunosuppression in 2.3%, smoking in 25%. Fever (97.2%), cough (97.2%), rhinnorhea (80.6%), and shortness of breath (58.3%) were the commonest symptoms. Radiographic abnormalities were interstitial/reticular infiltrates (30.6%), patchy consolidations (11.1%) and reticular shadows with areas of consolidation (25%). PaO2/FiO2 ratio was less than 200 in 27.8% cases. Thirty six percent cases had creatinine kinase (CK) levels greater than 400 U/L and lactate dehydrogenase (LDH) levels higher than 1000 U/L. Twenty seven percent cases were managed in ICU and 16.7% cases died during hospital stay. The 2009 pandemic H1N1 virus infection had a wide clinical spectrum with a potential to cause high morbidity and mortality. Early empirical antiviral therapy for hospitalized suspected influenza A (H1N1) is vital to prevent the rapid disease progression.