Tremor is divided into three groups: (1) resting tremor; (2) an action tremor, which is evident when the hand is held in a sustained position or against gravity; and (3) an intention tremor, which is present during movement. Physiological causes of tremor usually have clear precipitating factors, such as anger and exercise.

An action tremor that resolves when the limb is fully supported against gravity is characteristic of benign essential tremor; in addition it may also be relieved by alcohol and is attenuated during movement. Up to one-third of patients with benign essential tremor have a family history of it. In addition to tremor, patients with thyrotoxicosis may also complain of heat intolerance, palpitations, increased appetite with weight loss, anxiety and diarrhoea.

A detailed drug history will easily allow you to identify any drug that may potentially cause tremor. Enquiries should also include the amount of coffee and alcohol intake.

Associated symptoms of slowness, difficulty initiating and stopping walking, muscle rigidity and muscle fatigue (especially with writing) may be present with Parkinson’s disease. With cerebellar disease, difficulties may be experienced with balance and coordination.

Examination

Tremor

Observe the patient at rest: the presence of a pill-rolling tremor is suggestive of Parkinson’s disease. In addition, there may be expressionless facies, titubation and drooling of saliva. Thyrotoxic patients will be thin, with wide, staring eyes, lid lag, a goitre and exophthalmos with Graves’ disease.

The arms are then held outstretched; all other causes of tremor will now be visible. Fine tremors can be accentuated by placing a piece of paper on the outstretched hands. The arm should be fully supported and this will cause resolution of benign essential tremor. An intention tremor is demonstrated by the finger–nose test; a tremor is markedly increased when the finger approaches the target. In addition, there may also be past-pointing, where the finger overshoots the target.

General

Following this evaluation, further examination may be required to determine the underlying cause. The gait is assessed (p. 172) and differences between the parkinsonian and ataxic gait of cerebellar disease will be obvious. Further features of cerebellar dysfunction are scanning speech, dysdiadochokinesia, nystagmus and pendular reflexes. When thyrotoxicosis is suspected, the thyroid gland is palpated, ocular movements assessed and the thyroid gland auscultated for a bruit associated with Graves’ disease. Features of prolonged alcohol excess may be present (signs of chronic liver disease) and alcohol may lead to cerebellar degeneration.