Background: Influenza virus is associated each year with an excess of hospitalizations for pneumonia and acute pulmonary conditions in older persons. However, influenza is rarely tested in elderly patients admitted to the emergency department with pneumonia during influenza season.
Case Report: We report a case of a 78-year-old woman admitted to the emergency department in January 2007 for fever and dyspnea. On admission, she had a temperature of 38.8°C and dyspnea. There were wheezing on auscultation. Chest X-ray showed a bilateral interstitial infiltrate. It was concluded to pneumonia. Therapy with amoxicillin-clavulanic acid, oxygen and bronchodilatator aerosols was initiated and the patient was transferred after two days in our acute geriatric ward. On admission, it persisted an important wheezing on auscultation. As the patient had a productive cough, sputum for viral examination was collected, bacteriologic examination wasn’t performed due to antibiotics. Rapid detection test on sputum by direct fluorescent antibody assay (DFA) was positive for influenza A within few hours, confirmed by culture few days later. The patient was placed on respiratory isolation. No antiviral treatment was initiated due to the delay of diagnosis. The evolution was favourable and the patient was discharged from hospital after five weeks.
Conclusions: Influenza pneumonia is an underestimated diagnosis in elderly patients hospitalized with pneumonia during influenza season. Viral detection by immunofluorescent tests in sputum specimens can provide a rapid diagnosis and merits further evaluation. Early diagnosis permits to initiate appropriate infection control measures and antiviral treatment.

Keywords: immunofluorescent test, elderly, Sputum, influenza