Analysis of 113 hospitalized patients with confirmed 2009 influenza A (H1N1) virus infection

Authors: ESRAGÜL AKINCI, BİRCAN KAYAASLAN, MELTEM ARZU YETKİN, SEVİM YILMAZ, IŞIL DENİZ ALIRAVCI, SÜMEYYE YILDIZ, FATMANUR ÜLGEN, SELİM SIRRI EREN, AYŞE BUT, GÜLRUHSAR YILMAZ, OYA KILCI, NEVZAT MEHMET MUTLU, HATİCE YAĞMURDUR, HURREM BODUR

Abstract: To evaluate the demographic characteristics, clinical and laboratory features, underlying medical conditions, treatment, and outcome of hospitalized patients with laboratory-confirmed infection due to the 2009 influenza A(H1N1) virus. Materials and methods: This prospective study was performed between October and December 2009. The hospitalized patients with laboratory-confirmed diagnosis of 2009 influenza A(H1N1) virus infection were included in the study. The diagnosis was confirmed with detection of the virus in nasal and nasopharyngeal swabs by RT-PCR assay. Demographic and epidemiological characteristics, clinical features, treatment, and outcome of the patients were recorded on the individual forms. A comparison was made between patients with and without pneumonia. Results: From October to December 2009, 113 confirmed patients with 2009 influenza A(H1N1) virus infection were hospitalized in our clinic. The ages of the patients were between 17 and 77 years (mean age 35.7 ± 15.8 years) and 73 (64.6%) were female. Cough (92.9%), fever (85.8%), malaise (85.8%), headache (80.5%), and muscle aches (85.0%) were the most common presenting symptoms. The time from symptom onset to hospital admission was 1-15 days (mean time 3.8 ± 3 days). On physical examination, fever (74.3%), pharyngeal hyperemia (66.4%), rales (43.4%), dyspnea (29.2%), and cyanosis (4.4%) were the presenting clinical findings. Of the patients, 64 (56.6%) had at least 1 underlying medical condition. The most common underlying disease was chronic pulmonary disease (14.5%). A total of 25 patients were pregnant. On admission to hospital, 25 patients (22.1%) had leukopenia, 12 patients (10.6%) had leukocytosis, and 29 patients (25.7%) had thrombocytopenia. Pulmonary infiltrates consistent with pneumonia were detected on chest radiography in 47 (41.6%) patients.Of these patients, 98 (86.7%) received oseltamivir treatment on admission. Six patients (5.3%) were admitted to the ICU because of acute respiratory failure and 4 of them (3.5%) required mechanical ventilation. Among these patients, 3 (2.7%) died. A comparison between the patients with and without pneumonia was performed statistically. Age older than 40 years old, time from onset of symptoms to admission longer than 3 days, leukocytosis, ALT/AST elevation, and hyperglycemia were significantly higher in patients with pneumonia. Conclusion: Although the 2009 influenza A(H1N1) virus causes severe illness including pneumonia and death, the mortality rate is not very high. The characteristics of the disease are similar to those of seasonal influenza. Young adults were the most affected persons and most of the patients had underlying medical conditions.

Keywords: Influenza, H1N1, flu

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