An Unusual Case Presenting with New Onset Epileptic Seizure and Unilateral Temporal Lobe Lesion Diagnosed as Influenza Type A Associated Encephalitis.

Influenza A viruses, known etiological agents of seasonal outbreaks, epidemics, and pandemics, are RNA viruses of the Orthomyxoviridae family. They can manifest with a wide range of neurological complications. Influenza related encephalitis is rarely reported and poorly characterized in adults. Its diagnosis is hampered by significant variation in clinical presentation and difficulties in virus detection in the cerebrospinal fluid. Diffuse brain edema, symmetric involvement of thalamus, brain stem, and cerebellum, or normal findings in the acute phase followed by the appearance of diffuse low attenuation and mild brain atrophy are reported cranial magnetic resonance imaging findings, but unilateral temporal lobe involvement has not been observed before. Here we describe an unusual adult case who presented with new-onset epileptic seizures and unilateral temporal lobe lesion mimicking herpes simplex encephalitis but a polymerase chain reaction of cerebrospinal fluid confirmed influenza type A associated encephalitis.