Mollaret's Meningitis: CSF Cytology to the Rescue

Mollaret's meningitis refers to the classical description by Pierre Mollaret of recurrent episodes of fever and meningism lasting 2-5 days, followed by spontaneous recovery. It remains a rare entity and most often is attributed to reactivation of latent Herpes Simplex virus (HSV)-2 virus. Though considered self-limiting and innocuous, there are exceptional cases in which neurological sequelae have been reported. From a clinician's perspective, narrowing down the diagnosis may not be straightforward and would require judicious use of investigations. Here we report two cases of Mollaret's meningitis, both of whom had negative cerebrospinal fluid (CSF) polymerase chain reaction (PCR) for HSV. These reports also highlight an unusual pattern of presentation of this rare entity and the utility of CSF cytology in clinching the diagnosis.