Abnormal movements may be physiological or pathological, and characteristics help in classifying movement disorder and guessing probable aetiology. In this article, Dr. YK Amdekar takes us through this along with types of movement disorders, possible causes, and therapies.

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Types of movement disorders

They often are involuntary but occasionally voluntary and may be either hyperkinetic (increased movements) or hypokinetic (decreased movements such as in Parkinsonism). Hyperkinetic abnormal movements may include ataxia, dystonia, tremors, chorea, athetosis, myoclonus, hemiballismus, tics or Tourette syndrome.

Characteristics of movement disorders

Hyperkinetic

• Ataxia: Loss of truncal balance resulting in instability and swaying and/or intentional tremors (tremors on intentional movement of limbs – when made to move the limbs) and incoordination (as demonstrated by finger hand-to-nose test and many other clinical maneuverers) with hypotonia
• Dystonia: Increased muscle tone with twisting seen at rest or brought on by stimulation, sustained for a variable time
• Tremors: Distal, fast, rhythmic, small amplitude movements, may be seen at rest or on stimulation or stretching hands out; they may be physiological due to anxiety, stress or fear and are also seen in hyperthyroidism and liver cell failure.
• Chorea: Proximal, chaotic, fast, non-rhythmic, large amplitude with emotional instability and hypotonia
• Athetosis: Writhing movements, distal, slow, rhythmic, large amplitude, often together with chorea – choreoathetosis
• Myoclonus: Shock-like jerky movements of a group of muscles, fast, arhythmic, which at times may be benign as in sleep myoclonus with a normal neurological system
• Hemiballismus: Wide flinging movements of half side of the body (fly removal movement – movement while removing a fly coming on to your face), large amplitude
• Tics: Suppressible, paroxysmal stereotype muscle contractions
• Tourette syndrome: Frequent, repetitive, jerky localised movements often involving the face and neck with vocal tics in the form of grunting, throat clearing, shouting or barking, usually getting better by the age of 20 years

Hypokinetic

These are slow movements as shuffling gait in Parkinsonism with other features such as tremors, stiffness of limbs and trunk, incoordination and impaired balance.

What are the causes?

• Immune-mediated (rheumatic chorea)
• Infection (TB meningitis with choreoathetosis and hemiballismus)
• Genetic (degenerative disorders)
• Metabolic disorders (Wilson disease)
• Vascular (strokes)
• Tumour (cerebellar tumour)
• Toxins (chronic hepatic disease or inborn error of metabolism)
• Drugs (anti-emetic, anti-convulsant)

Clinical approach

1. The first step is to characterise abnormal movement based on the following criteria (as depicted above). proximal or distal, fast or slow, rhythmic or arhythmic, small or large amplitude. This may be confirmed by observation or supporting clinical maneuverers. The typical characteristics may help guess probable aetiology based on common presentation.
2. The second step is to confirm that abnormal movement is definitely pathological as tremors or myoclonus may be physiological.
3. The third step is to ascertain if the abnormal movement is the only abnormality or whether there is evidence of affection of other areas of the brain.

Presence of other symptoms and signs such as a change in sensorium, pyramidal tract signs, cerebellar signs, meningeal signs, cranial nerve affection and evidence of involvement of other systems such as liver or thyroid disease. Thus, the anatomy of the disease can be found out.

Pathology and aetiology are guessed on the history of presentation (acute, subacute or chronic, static or progressive) as well as past history (rheumatic fever), family history (consanguinity as in Wilson disease) and drug history.

Investigations

Provisional diagnosis is a prerequisite to ordering tests. Obviously, specific tests may vary in each case.

1. CT or MRI scan may show basal ganglia lesion and affection of other areas if any. But may not be necessary in each case. For example, diagnosis of rheumatic chorea is often clinical with typical presentation and neuro-imaging will not help in defining the cause.
2. Stroke may be confirmed with neuro-scan and if performed in the early stage, damage can be reversed.
3. CNS infection can be diagnosed with CSF examination, Wilson disease is confirmed with biochemical tests.
4. Tics do not justify any tests.

Treatment

Symptomatic therapy: Abnormal movements may be controlled by drugs such as Haloperidol for rheumatic chorea, levodopa or beta-blocker for Parkinson tremors and other drugs like antidepressants and anticholinergics. The duration of symptomatic treatment depends on the natural progress of the condition. Abnormal movements in rheumatic chorea are usually controlled in few weeks but at times they may recur. Prolonged treatment is necessary for degenerative conditions.

Specific therapy: It depends on the cause. For example, Penicillamine for Wilson disease, anticoagulant and aspirin for strokes, anti-infective for infections and penicillin prophylaxis for rheumatic chorea as per the standard guidelines.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.