An unusual presentation of herpes simplex encephalitis with negative PCR

A 74-year-old man presented with acute right-sided hemiparesis and epilepsia partialis continua in association with fever and confusion. Initial workup revealed possible cerebritis in the left medial frontal lobe without involvement of the temporal lobes. Cerebrospinal fluid (CSF) analysis revealed minimal lymphocytic pleocytosis but negative real-time herpes simplex virus (HSV) PCR. Acyclovir was discontinued on day 5 due to a negative infectious workup and clinical improvement. On day 9 his condition deteriorated and he was transferred to a higher level of acuity for advanced supportive care. Worsening encephalopathy and refractory status epilepticus ensued despite medical care. Repeat CSF analysis showed mild lymphocytic pleocytosis with negative real-time HSV PCR. Brain MRI revealed progression of cortical enhancement. Immunosuppressive therapy and plasma exchange were attempted without clinical response. On day 24, another lumbar puncture showed only mild lymphocytic pleocytosis. Brain MRI showed involvement of the right medial temporal lobe. Subsequently, acyclovir was resumed. The HSV-1 PCR result was positive on day 30. Unfortunately, the patient expired.