Movement Disorders

Movement disorders* * Except Parkinsonism and tremor Submitted to AskTheNeurologist.Com in 2007 Author Anon.

What is a Movement disorder? “ A disorder which impairs the regulation of voluntary motor activity without directly affecting strength, sensation or cerebellar function ” Sometimes also known as “ extrapyramidal disorders” Many neurologists restrict the term “ extrapyramidal” to refer only to Parkinsonism

Types of abnormal movement Myoclonus Ballismus Chorea Athetosis Dystonia Tics Tremor ( discussed elsewhere )

Myoclonus “ sudden, brief, shock-like involuntary movements” May be caused by active muscle contraction - positive myoclonus May be caused by inhibition of ongoing muscle activity - negative myoclonus ( eg. Asterixis ) Generalised - widespread throughout body Focal / segmental – restricted to particular part of body

Generalised myoclonus Physiologic - Nocturnal ( usually on falling asleep ) - Hiccups Essential - Occurs in the absence of other abnormality - Benign and sometimes inherited Epileptic - Demonstrable cortical source Symptomatic i.e secondary to disease process - Neurodegenerative eg. Wilson’s disease - Infectious e.g CJD, Viral encephalitis - Toxic e.g. penicillin, antidepressants - Metabolic - anoxic brain damage - hypoglycemia - hepatic failure ( “ asterixis” ) - renal failure - hyponatremia….. And others

Segmental Myoclonus Can arise from lesions anywhere in the CNS Can arise from many of the processes that can cause generalised myoclonus Example is “palatal myoclonus” which arises due to any lesion that interrupts pathway between red nucleus, cerebellum and olivary nucleus.

Treatment of Myoclonus Valproic acid is drug of choice May respond to benzodiazepines e.g. clonazepam

Ballismus, Chorea, Athotosis and Dystonia These should NOT be thought of as separate entities amenable to specific definition but rather as a SPECTRUM of movements that blend into one-another WHY?

Because…….. They often co-exist Even neurologists may often not be able to agree as to how a particular movement should be classified! They often ( with some notable exceptions ) have the same significance in terms of aetiology.

The spectrum Ballismus Dystonia Chorea Athetosis Movements become - Less violent / explosive / jerky - Smoother and more flowing - More sustained They differ from tics in that they cannot be suppressed by voluntary control

Ballismus Violent “flinging” movement of entire limb Almost always unilateral and therefore use term “ HEMIBALLISMUS” Involves proximal musculature and is sometimes thought of as a “ proximal unilateral chorea ” Usually due to a CVA in contralateral subthalamic nucleus

Chorea ( “dance” in Greek) Rapid irregular muscle jerks May affect limbs, head, face and tongue In the limbs chorea refers more to distal movements ( as proximal movements usually called ballismus) Patients often attempt to conceal involuntary movements by superimposing voluntary movements onto them e.g. an involuntary movement of arm towards face may be adapted to look-like an attempt to look at watch

Athetosis “ changeable” in Greek Slow, flowing, often twisting movements Occurs mainly distally ( hands, fingers) Can also affect face and tongue Often use term “ choreoathetosis ” due to overlap between syndromes ( chorea referring to less smooth , more jerky movements)

Dystonia “ condition in which the patient assumes a sustained, abnormal posture or limb position” Due to co-contraction of agonist and antagonist muscles in part of body Can be thought of as an athetoid movement that “gets stuck” for a period of time; thus, a patient with choreoathetosis may perform an involuntary movement in which his hand and fingers are twisted behind his head. He may hold this position for a few moments before his hand moves back in front of his body. The part of the movement when the limb was held, unmoving, in an abnormal position would be considered a dystonia ( may occur alone).

Examples of focal dystonias Blepharospasm: - involuntary forceful closure of eyes Torticollis: - Tendency of neck to twist to one side. Writer’s cramp: - Dystonic posturing of arm when hand used to perform specific tasks e.g. writing, playing piano

Botulinum toxin Derived from Clostridium botulinum Prevents pre-synaptic release of Ach vesicles and therefore blocks neuro-muscular junction transmission May be injected selectively into muscles responsible for focal dystonias, allowing relief for up to several months Requires expertise; can cause more extensive paralysis than intended.

Causes of Chorea, Dystonia and athetosis Hereditary Static Encephalopathy ( Cerebral Palsy ) Drugs Cerebrovascular ( ischaemia, haemorrhage ) Structural lesions ( subthalamic nucleus) Secondary to medical disorders Miscellaneous - Sydenham’s chorea - Chorea Gravidarum - Sporadic idiopathic torsion dystonia - Focal dystonias

Hereditary Huntington’s disease Wilson’s disease Neuroacanthocytosis Hereditary dystonias - idiopathic torsion dystonia - dopa - responsive dystonia

Wilson’s disease Autosomal recessive defect of copper excretion in which there is defective copper-binding to ceruloplasmin Leads to copper deposition in: - liver causing cirrhosis - brain ( especially basal ganglia ) leading to movement disorders and other abnormalities - Cornea leading to the appearance of rusty brown “ Kayser-Fleischer rings” around cornea (usually only seen with slit-lamp). Diagnosis is via low serum ceruloplasmin, increased urinary Cu, liver biopsy ( excessive Cu) and brain MRI changes Although it is rare it is very important to think-of and diagnose as it is TREATABLE:- Penicillamine is given to chelate the copper and promote excretion.

Idiopathic torsion dystonia Hereditary and sporadic forms Variable inheritence High incidence in Ashkenazi Jews Onset may be in childhood / adulthood Affects limbs, trunk, neck, face Trial of L-dopa usually initiated Level of disability variable

Dopa-responsive dystonia Autosomal dominant inheritence Onset usually in childhood Girls more severely affected Some parkinsonian features - rigidity - bradykinesia Low levels of L-Dopa very effective

Drug-induced Drugs acting on dopaminergic system - Antiparkinsonian - Antipsychotic Lithium Phenytoin Oral contraceptives

Anoxic brain damage ( post – CPR ) Systemic lupus erythematosis Hepatic failure Endocrine - Thyrotoxicosis - Addisons Electrolyte - Low Ca, Mg, - High Na Polycythemia rubra vera Secondary to medical disorders (A SHEEP)

Sydenham’s chorea Mainly children / adolescents Complication of previous group A streptococcal infection Usually no recent history of infection Acute / subacute onset May have behavioural problems Usually remits spontaneously

Chorea gravidarum Chorea of any cause that begins in pregnancy May represent recurrence of Sydenham’s chorea. Most commonly associated with anti-phospholipid syndrome +/- SLE Usually resolves spontaneously

Tics Recurrent, sterotyped abnormal movements May be suppressed voluntarily or with distraction Voluntary suppression leads to anxiety and a build-up of internal unrest. Worsen under stress

Summary Movement disorders are often difficult to define precisely, but have similar differential diagnoses. They are often a manifestation of a more widespread neurological or internal medical problem. Other than the specific treatments mentioned, most details of therapy are beyond the scope of this course. In some cases treatment includes treatment of underlying cause e.g. Wilson’s disease

Submitted to AskTheNeurologist.Com in 2007 Author Anon.

Movement Disorders

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Movement Disorders