Acute Febrile Encephalopathy with Rigidity.

Febrile encephalopathy with rigidity can be the presenting feature of several life-threatening neurological emergencies such as neuroleptic malignant syndrome (NMS) and serotonin syndrome. Although the pathogenesis of these conditions is poorly understood, we review advances in our understanding of underlying genetic and other biological mechanisms. We also discuss the complex and expanding differential diagnoses which include other drug-induced hyperpyrexia or rigidity syndromes (eg malignant hyperthermia, parkinsonism-hyperpyrexia syndrome, malignant catatonia) as well as autoimmune syndromes. Finally, we consider potential predictive and preventative approaches along with best practice management strategies.