[Neuroleptic malignant syndrome in patients with non-herpetic viral encephalitis. Study of 7 cases]

Our aim was to consider the possibility that patients with viral non-herpetic viral encephalitis develop the neuroleptic malignant syndrome (NMS) and determine the indispensable elements to diagnose it.

Seven patients with this type of encephalitis whose clinical picture fulfilled the criteria for NMS were evaluated. The control group consisted of 17 patients with the same type of encephalitis who had been randomly selected from the Neurological Service of a 3rd level hospital. We compared blood leukocyte numbers, cerebrospinal fluid (CSF) findings, axilar temperature, creatine kinase (CK) values and number of days of hospitalisation.

There were 5 males and 2 females with the mean age of 26 years. The control group consisted of 10 males and 7 females with an mean age of 37.52 years. Patients developed NMS after they were exposed to a mean doses of 17.85 mg of haloperidol with a latency (up to onset of symptoms) of 27.42 hours. In patients with NMS, the total number of leukocytes was increased (p < 0.003) as was that of neutrophils (p < 0.0003); the CSF protein level was increased (p < 0.02) whereas the CSF glucose level was reduced (p < 0.004); hyperpyrexia was higher (p < 0.000001); serum CK levels were higher (p < 0.000001), and, finally, NMS patients spent more days in hospital (p < 0.0002) than the control group.

Patients with non-herpetic viral encephalitis can develop NMS after being exposed to relatively low doses of haloperidol and after a short latency period. The criteria typical of NMS including rigidity, hyperpyrexia, autonomic instability, altered consciousness and high CK levels are critical elements for its diagnosis. Moreover, these patients had high protein and low glucose CSF levels and they require more days of hospitalisation.