Activation of HSV Encephalitis after MVD for TN

We present the first reported case of herpes simplex encephalitis (HSE) precipitated by trigeminal nerve microvascular decompression.

A 29-year-old woman with a long-standing history of treatment for refractory trigeminal neuralgia (TN) underwent an elective microvascular decompression (MVD) of the right trigeminal nerve. She was discharged as planned without complications. One week postoperatively she was admitted with pyrexia, photophobia, neck stiffness, and nausea and vomiting. She was initially started on Ceftriaxone for a clinical diagnosis of bacterial meningitis. But CSF serology was positive for herpes simplex virus (HSV) type 1. Her antibiotics were stopped and replaced by IV acyclovir. She improved very quickly after this treatment and was subsequently discharged.

Although studies have showed that reactivation of latent HSV is not uncommon following neurosurgical intervention, developing HSE is an extremely rare complication with a high mortality rate. There is some evidence that prophylactic acyclovir can reduce HSV reactivation postoperatively, though its use is questionable. We suggest HSE should be considered in any patient presenting with encephalitic picture following MVD to avoid delay in antiviral therapy.