An 82-year-old male Bangkokian with hypertension, diabetes mellitus, end-stage renal disease, and
coronary artery disease for many years, was hospitalized due to deterioration of a 3-day influenza-like-illness
with one-day chest oppression and respiratory failure. At the emergency room, oxygen saturation was 79% on
room air. Chest X-ray revealed bilateral diffuse pulmonary infiltrates. He was intubated and hemodialysis was
initiated. Emergency coronary angiography revealed patent coronary artery. Sputum gram stain revealed
numerous leukocytes with no bacteria. On day three of hospitalization, empiric treatment with oseltamivir
and clarithromycin was administered. Seventy-two hours later his clinical condition began to improve and
fever subsided 7 days later. Rapid test of tracheal secretion with immunofluorescence assay was positive for
moderate amount of influenza A virus. Viral isolation yielded influenza A virus subtype H1N1. Review of inpatient
records at this hospital using ICD-10 codes as J10 and J11 during 1995-2005, discovered 32 cases
with claim diagnosis of influenza. However, this is the first case with proven influenza pneumonia that was
given empiric oseltamivir. Rapid deterioration of influenza-like illness due to human influenza virus in the
elderly and pathogenesis of pulmonary in this case are discussed to alert physicians to recognize this dreadful
illness and treat it in timely fashion.

Keywords: Influenza A virus, Influenza pneumonia, Influenza, Oseltamivir