Clinical manifestations and complications of hospitalized patients with severe H1N1 influenza infection during the winter of 2013 -2014
The 2013 - 2014 influenza season showed widespread influenza like activity associated with significant morbidity and mortality. 2009 pH1N1 predominated and accounted for 96% of reported influenza A viruses.
Demographic, clinical, laboratory and outcome data from all adult patients admitted with severe H1N1 influenza were collected during 2013-14 influenza season.
We identified 64 adult patients (44% male). Median age was 55.5 years (70% white). Common comorbidities included COPD (27%), CAD (25%), Obesity (50%) and smoking history (43%) (Figure1). Median time from symptom onset to hospitalization was 5 days. Most common presentation was cough (75%), fever (73%), shortness of breath (72%) and myalgia (70%). In the emergency room, 58% had tachycardia, 16% were hypotensive and 33% had oxygen saturation less than 90% on room air. Among 60 patients that had a positive H1N1 PCR, 54 has a concomitant rapid flu test within 24 hours; only 8 was positive with Sensitivity of 17%. Pathogens commonly co-detected by PCR were: MRSA (17%), Pneumococcus, Hemophilus Influenza and pseudomonas (5%) and RSV in 3%. Chest radiographs were negative in 34% and showed pneumonia in 66%. CT chest was done in 24 patients showing multi-lobar involvement with 33% had Extensive Bilateral Infiltrates. Steroids given in 57% and did not affect outcome. 42 patients admitted to the ICU. 42% needed Mechanical ventilation. Median duration of ICU stay and ventilation was 8 and 6 days respectively. Fatality rate was 23%; 27% had no risk factors for severe influenza infection. Most common complications were adult respiratory distress syndrome (34%) and acute renal failure (34%) (figure 2). Hemodialysis used in 6% of those who developed renal failure. Of 26 patients with known vaccination status, only 5 were vaccinated.
Patients with severe pH1N1 infection were most likely middle age, obese with history of smoking. They presented late in the disease most commonly with respiratory distress. Significant number needed ICU admission, mechanical ventilation and pressers. It was associated with significant complications and high fatality rate. In addition, rapid influenza testing had very low sensitivity, which calls for PCR testing in all hospitalized pa