Other movement disorders

Essential tremor

Essential tremor is a common problem, with a prevalence of 3 in 1000. It is a slowly progressive 5–8 Hz tremor that is postural and worse on action. It is usually asymmetrical, involving the hands and affecting writing and fine movements (Fig. 1). It may affect the head (yes-yes head titubation). Patients usually present later in life but have generally been aware of the tremor for many years. About 60% of patients will notice a marked improvement with small amounts of alcohol. About half the patients have a family history when the inheritance is dominant.

Fig. 1 Writing in essential tremor. Note the spiral has become larger (cf. Parkinsonism).

The diagnosis is clinical. Most patients respond well to propranolol. Primidone, an anticonvulsant, may be useful if beta-blockers are contraindicated or ineffective. Very occasionally, in severely affected patients, stereotactic thalamotomy may be needed.

Other tremors

Physiological tremor. A tremor of 8–12 Hz that is normally present but can be enhanced by anxiety, hyperthyroidism, drugs (such as beta agonists or sympathomimetics) and alcohol withdrawal.

Cerebellar tremor. A slower tremor (3 Hz) that increases as the limb is moved towards the target (intention tremor). There may be yes-yes head titubation.

Rest tremor. See section on Parkinsonism.

Orthostatic tremor. A rare tremor which appears in the legs on prolonged standing. It is treated with clonazepam, gabapentin and levodopa.

Cervical dystonia

This is a common condition. The involuntary contraction in the neck muscles results in:

abnormal head movements

abnormal head position

neck pain.

The direction of movement and abnormal head position vary depending on which muscles are overactive. For example, if one sternocleidomastoid is overactive, the head will turn to the opposite side; if both splenius capitis are affected, the head will look up (retrocollis). Often the patient will be aware that a particular manoeuvre, for example touching the cheek in a certain position (referred to as a ‘geste’), can stop an abnormal movement.

In most patients no cause is found. Sometimes this can be triggered by neuroleptics or, occasionally, structural lesions in the basal ganglion.

Patients can be treated symptomatically with botulinum toxin. This toxin weakens the affected muscle for 3–4 months, so relieving symptoms. Side effects are infrequent, mostly producing weakness in the treated muscles or, rarely, adjacent muscles, for example muscles of speech and swallowing.

Writer’s cramp and other task-specific dystonias

These conditions, of unknown aetiology, were previously considered to be psychiatric. During a specific activity, an abnormal tension and posture develop in the hand. This most commonly occurs during writing, but has been associated with a range of skilled motor tasks such as typing, playing the guitar or playing darts. In writer’s cramp, the way the pen is held often changes and the patient may complain of breaking pens and pressing very hard on the paper.

The response to treatment is poor. Patients do best if there are ways of avoiding the activity involved, for example moving from handwriting to using a computer. Occasionally botulinum toxin can help.

Blepharospasm

This is an uncommon problem where the eyes close involuntarily. This can be sufficiently severe to render the patient effectively blind. It responds well to botulinum toxin injections.

Other focal dystonias

Spasmodic dysphonia. This is rare. Speech is variable and often has a high-pitched strangled quality; it may be tremulous.

Oromandibular dystonia. The mouth and tongue are affected and the jaw may close on the protruded tongue.

Both conditions respond to botulinum toxin.

Wilson’s disease

This is a rare (3 per 100 000) but very important disease because it requires specific treatment to prevent deterioration. This condition needs to be considered in all young patients with unusual neurological or psychiatric problems.

There is a defect in copper metabolism, which leads to an accumulation of copper in the liver and the basal ganglia. It has autosomal recessive inheritance.

The presentation is variable. Children may present with liver problems, psychiatric disturbances or a wide range of movement disorders, most notably tremor, Parkinsonism, dysarthria and incoordination. The finding of Kayser–Fleischer rings, brown corneal deposits that can be seen with a slit lamp, is said to be pathognomonic. Diagnosis depends on a low blood copper and caeruloplasmin and an elevated 24-h urinary copper.

Treatment is with chelating agents such as d-penicillamine or oral zinc, which impairs copper absorption.

Chorea

Chorea is a term used to describe abnormal movements that are fidgety and twitchy with no position being sustained. If the movements are mild, they can be made to look semipurposeful.

Hemiballismus

This is a more dramatic movement of one side of the body, which is thrown around violently, sometimes injuring the patient. This usually arises from vascular lesions of the contralateral subthalamic nucleus. Hemiballismus usually resolves spontaneously.

Tic syndromes

Tics are stereotyped movements. They are voluntary movements undertaken to satisfy an inner urge. They can be suppressed temporarily. They can occur in the absence of other neurological problems, simple motor tics, or be associated with the utterence of obscenities (Gilles de la Tourette’s syndrome), other neurological problems (previous head injury or stroke) or neuroleptic drug administration. They can be suppressed with clonidine or risperidone.

Myoclonus

Myoclonus is the occurrence of sudden, shock-like involuntary movements. It can occur in epilepsy as a form of seizure (p. 74) and normally in association with sleep. It can occur without other neurological deficits (essential myoclonus), when it usually responds to clonazepam or sodium valproate. It is a prominent feature in postanoxic encephalopathies and some neurodegenerative diseases.

Restless legs syndrome (Ekbom’s syndrome)

This is an unpleasant sensory feeling occurring in the legs, particularly at night, that is relieved by moving the legs. It may occur with a peripheral neuropathy, iron deficiency, uraemia or lumbar spondylosis, but is usually idiopathic. Dopamine agonists (pramipexole or ropinerole) are often effective and clonazepam or levodopa may help.

Hemifacial spasm

This is an uncommon problem that usually occurs later in life. There are episodes where half the face briefly goes into spasm; these may almost appear rhythmical at times. This is usually due to compression of the facial nerve by an aberrant posterior fossa vessel: microvascular compression. The spasms may remit spontaneously. Treatment with botulinum toxin is effective. If symptoms are severe and the patient is otherwise well, a microvascular decompression of the nerve is effective.

Drug-induced movement disorders

Acute

Oculogyric crises occur in about 2% of patients given neuroleptics (including the antiemetics prochlorperazine and metoclopramide) and particularly occurs in young men. The effect is dramatic: the jaw clenches, the face grimaces, there is marked torticollis and retrocollis and there may be opisthotonus (back muscles going into spasm and hyperextending the back). Treatment is with intravenous anticholinergics, followed by oral anticholinergics, and is equally dramatic.

Neuroleptic malignant syndrome (p. 121)

This is the onset of rigidity, fever, autonomic disturbance and impaired consciousness associated with an elevated creatine kinase. It can occur at any time in association with neuroleptics. Therapy involves withdrawal of the neuroleptics, antiparkinsonian drugs and dantrolene and appropriate support. Mortality can be as high as 25%. Serotonin agonists and ‘ecstasy’ can cause a similar syndrome.

Parkinsonism

Neuroleptics can produce an akinetic rigid syndrome indistinguishable from idiopathic Parkinson’s disease. Older patients are more likely to be affected. This may improve over months despite continued neuroleptic therapy. Anticholinergics and amantadine are the only therapies available.

Akathisia

This is a very common problem in patients on long-term neuroleptics. It consists of a motor restlessness manifested as stepping up and down on the spot, or leg swinging. This is usually resistant to treatment.

Tardive dyskinesias

Tardy means late and tardive dyskinesias are movements that occur either after prolonged therapy or some time after drug exposure. The most characteristic is the orolingual dyskinesia – a repetitive lip smacking and chewing – but most movement disorders mentioned above have been described in association with neuroleptics. A detailed history of previous exposure to neuroleptics is essential in assessing anyone with a movement disorder.

Other movement disorders

Essential tremor responds to beta-blockers.

Cervical dystonia, blepharospasm, hemifacial spasm and some focal dystonias are treated effectively with botulinum toxin.

Wilson’s disease should be considered in all younger patients with movement disorders or psychiatric illnesses.

Neuroleptic drugs can provoke all types of abnormal movement.