West Nile virus encephalitis with myositis and orchitis.

This report documents the hospital course and autopsy findings of a 43-year-old man with a renal allograft who died of West Nile virus (WNV) encephalitis. Central nervous system (CNS) findings were those of severe necrotizing and hemorrhagic encephalitis affecting gray matter regions limited to the diencepahlon, rhombencephalon, spinal cord, and limbic system. The bilateral process exhibited preferential involvement of motor neurons. Brain imaging obtained 6 days before death demonstrated an unusual pattern of involvement corresponding with the autopsy findings, confirming that imaging may be a specific diagnostic guide in WNV encephalitis. Extra-CNS findings include myositis with T-lymphocyte infiltration of nerve fibers, suggesting that the virus may reach the CNS via peripheral nerves. Orchitis with dense T-lymphocyte infiltration and syncytial cell formation thought to be due to WNV were also noted.