Trismus
AETIOLOGY AND PATHOGENESIS
Trismus is usually caused by inflammation and masticatory muscle spasm, or inflexible scarring or other tissues (Boxes 23.1 and 23.2). Life-threatening causes include tetanus, malignant neoplasms and fascial space infections. In stroke patients, trismus may appear as a sequel to the CNS dysfunction. Some psychotomimetics (e.g. amphetamines and ecstasy (methylenedioxymethamphetamine; MDMA)) can cause masticatory muscle spasm which forcibly causes bruxism and difficulty in mouth opening, which can be reduced by sucking on a pacifier or lollipop. In some mental states such as hysteria, it may appear that the patient has trismus.