Herpes Simplex Virus Encephalitis in a Post-operative Case of Follicular Thyroid Carcinoma.

Herpes simplex virus (HSV) encephalitis is a life-threatening consequence of HSV infection of the central nervous system. Early antiviral therapy is most effective, necessitating prompt diagnosis. We report a case of atypical HSV encephalitis. The appearance of a strong headache followed by impairment of consciousness during the postoperative course in a 70-year-old patient who underwent surgical removal of a follicular thyroid carcinoma. Diffusion-weighted MRI detected brain abnormalities on the second day after the onset of symptoms, and polymerase chain reaction identification of HSV-1 DNA confirmed the diagnosis. A positive prognosis was achieved due to the decision to start specific, high-dose antiviral therapy based on clinical suspicion. A firm diagnosis was established by Tzanck smear and polymerase chain reaction.