Hallett reviews the classification and treatment of tremors, which are involuntary rhythmic oscillations of a part of the body. Tremors can be classified by the way in which the tremor appears (see table).
The only important tremors at rest are those of Parkinson's disease and drug-induced parkinsonian-like states. These tremors respond to therapy with dopaminergic agents or anticholinergic agents, such as trihexyphenidyl hydrochloride.
Postural tremors, which appear when the patient is asked to assume a posture
Classification of Common Tremors
such as raising the arms parallel to the floor, may have several causes. The most common postural tremor is essential tremor. Usually occurring in the upper extremities, essential tremor may be inherited as an autosomal dominant trait. Beta blockers, such as propranolol, are helpful in about 70 percent of patients.
Cerebellar dysfunction is the usual cause of kinetic (or intention) tremor without a postural aspect. The tremor is characterized by rhythmic oscillations about the target. No specific therapy is available.
Task-specific tremors have recently been recognized and distinguished from essential tremor. An example is primary writing tremor, which affects handwriting but not other fine motor activity. This tremor responds to treatment with anticholinergic medication or beta blockers.
Tremor may also be a conversion symptom. Hysterical tremors can take many forms, but are usually tremors with movement. A patient with hysterical tremor should be referred for psychiatric diagnosis.
Because appropriate therapy for tremor depends on making a correct diagnosis, care should be taken in the classification of these movement disorders. (JAMA, August 28, 1991, vol. 266, p. 1115.)
COPYRIGHT 1991 American Academy of Family Physicians
COPYRIGHT 2004 Gale Group