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.