Tremor

Chorea

Chorea describes involuntary, rapid, jerky movements which often move from one part of the body to another. Slower, sinuous movement of the limbs is termed athetosis. Chorea is caused by damage to the basal ganglia, especially the caudate nucleus.

Causes of chorea

• Huntington's disease, Wilson's disease, ataxic telangiectasia
• SLE, anti-phospholipid syndrome
• rheumatic fever: Sydenham's chorea
• drugs: oral contraceptive pill, L-dopa, antipsychotics
• neuroacanthocytosis
• pregnancy: chorea gravidarum
• thyrotoxicosis
• polycythaemia rubra vera
• carbon monoxide poisoning
• cerebrovascular disease

Dystonia

Focal dystonia can present as unilateral blepharospasm.

The history of periodic involuntary eye closure that can be provoked by external stimuli (eg, bright light or irritants) is typical.  Older women are particularly predisposed to this condition.  A potential explanation is that dry eyes in postmenopausal women may serve as a trigger for blepharospasm.  Botulinum toxin injections are the mainstay of treatment.  They can be used for many years without any loss of efficacy or significant side effects.