[Diagnosis of trismus, excluding tetanus and local causes]

The most frequent causes of trismus are tetanus and local lesions. This report discusses other etiologies. Trismus is usually only a secondary sign of a rich clinical picture, but may be of diagnostic value in some cases. Emphasis is placed on the frequency of involvement of neuroleptic intoxication, the early onset of trismus in the malignant hyperthermia syndrome, and on the useful role of trismus in the localization of neurological lesions.