Novel influenza A (H1N1) virus–induced hemophagocytosis: first case reported in Saudi Arabia

H1N1 is a novel subtype of the influenza A virus. Since its reemergence in 2008, it has been reported to cause a variety of illnesses ranging from mild flu-like symptoms to severe multiorgan failure. We report a case of a young immunocompetent man who presented with progressive shortness of breath and rapidly developed multiorgan dysfunction, including pancytopenia from H1N1 infection during the 2010–2011 influenza season. His H1N1 pneumonia caused severe acute respiratory distress syndrome, respiratory failure requiring mechanical ventilation, rhabdomyolysis, myocarditis, hepatitis, encephalitis, and renal failure. During the diagnostic workup, a bone marrow biopsy was performed, showing hemophagocytosis secondary to the H1N1 infection. Unfortunately the patient died despite aggressive measures. Published reports contain only a few records of H1N1-induced hemophagocytosis. This is the first case report from Saudi Arabia with H1N1-induced secondary hemophagocytosis. It also highlights the fact that the virus is still very virulent and will pose a major annual health risk along with the seasonal influenza for at least the next few years.