ABSTRACT

Neuroleptic malignant syndrome (NMS) and malignant hyperthermia (MH) have both been recognized since the 1960s and are usually diagnosed by psychiatrists or anesthesiologists. Furthermore, MH was diagnosed in an acute clinical setting of succinylcholine induction associated with halogenated anesthetics for surgical procedures, whereas NMS was apparent over several hours or days (subacute) and included neuropsychiatric manifestations in patients on neuroleptics. Serotonin syndrome (SS) was also recognized in the 1960s but has come into prominence with the increased use of selective serotonin reuptake inhibitors (SSRIs) as antidepressants. However, overlap features were readily recognized and included autonomic nervous system (ANS) instability, variable temperature elevations, and muscular rigidity with increased serum creatine kinase (CK) levels. Recently, with increased understanding of the role of calcium homeostasis in neuronal and muscle excitability, such as excitation-contraction coupling (muscle) and neurotransmitter release (neuronal), investigators have questioned a common pathophysiology for these disorders due to defects in calcium metabolism and homeostasis.