Movement disorders

Movement Disorders

Some time called (extra-pyramidal motor disorders)

They impair the regulation of voluntary motor activity without directly affecting strength, sensation, or cerebellar function. They classified into:hyper-kinetic disorders associated with abnormal, involuntary movements ex: tremors.hypo-kinetic disorders characterized by poverty of movements ex: Parkinson’s disease.Both types result from dysfunction of basal ganglia (BG) “caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra (STN)”.

Tremors

A tremor is an involuntary rhythmic oscillation of a limb or part of a limb at a joint.4 types: static tremor or rest tremor: occurs when the limb is at rest. Examples are: ParkinsonismWilson disease Heavy metal poisoning (eg, mercury) postural tremor: present during sustained posture but it’s severity does not increased by movement. Examples are: Physiologic tremor, Familial (autosomal dominant) or idiopathic (benign essential) tremor Cerebellar disorders Wilson diseaseintention tremor: appear during movement but not at rest, & its severity increased while approaching the target. Examples are:Brainstem diseasecerebellar disease Drug toxicity (eg, alcohol, anticonvulsants like phenytoin, sedatives) Wilson disease4. Flapping tremor or Asterixis: sudden flexion of over extended wrists at overstretched forearms followed by a return to extension occurring repeatedly owning to episodic cessation of muscular activity, so that the hands flap. It is due to intermittent failure of ability of both parietal lobes to maintain a limb in a fixed posture. It occur in metabolic encephalopathy such as:hepatic failure. renal failure.Respiratory failure type 2Heart failureNarcotic drug poisoning N.B: Both postural and intention tremors are also called action tremors.

Familial, or Benign, Essential Tremor

A prominent postural tremor in otherwise normal subjects. it often has a familial basis with an autosomal dominant mode of inheritance may develop in the teenage or early adult years but often do not appear until later (senile tremor). The tremor typically involves one or both hands or the head and voice The legs tend to be spared. it generally leads to little disability other than cosmetic and social embarrassment relieved remarkably but transiently by a small quantity of alcohol (pathognomic feature)

Treatment:Propranolol, 40–120 mg orally twice daily Primidone (50-750 mg/d in divided doses) start by 25 mg/d at bed time then the daily dos increased slowly by 50 mg every 2 weeks. (usually 100 or 150 mg three times a day enough) Alprazolam, up to 3 mg/d in divided doses occasionally benefit.Other drugs like: Topiramate, Gabapentin are of occasional benefit.Thalamotomy or high-frequency thalamic stimulation in case of failure of pharmacological treatment.

Chorea

It is quasi-purposive involuntary movements of intermediate velocity affect distal parts of limbs, facial grimace, or tongue. In mild cases, there will be just a persistent restlessness and clumsiness. there may be difficulty in maintaining muscular contraction such that, for example, hand grip is relaxed intermittently (milkmaid grasp). The gait becomes irregular and unsteady, with the patient suddenly dipping or lurching to one side or the other (dancing gait). Speech often becomes irregular in volume and tempo and may be explosive in character. Associated with hypotonia

Causes:Sydenham's choreaCerebral palsy Hereditary diseases: Huntington’s disease, Wilson's disease, Neuroacanthocytosis, Porphyria, Paroxysmal choreo-athetosis, benign hereditary choreaDrugs likeDopaminergic drugs like L-dopa & Bromocriptine Dopamine blockers like traditional antipsychoticIsoniazidLithiumReserpineoral contraceptives5. Pregnancy (chorea gravidarum)6. Metabolic thyrotoxicosis, hypoparathyroidism, hypomagnesemia7. Systemic lupus erythematosus8. Stroke 9. Tumor10. Subdural hematoma


Most common cause of chorea in middle age or elderly is drug induced chorea: “pateint with Parkinson’s disease on excessive dose of dopaminergic medications like L-dopa or Bromocriptine leading to over-dopaminergic state in basal ganglia” , while the most common cause of chorea is young patient is Sydenham’s chorea.

Chorea treated by:- Treat the underlining cause if possible.Dopamine receptors blockers like haloperidol (Serenace)®, 0.5–4 mg orally four times daily, or chlorpromazine (Largectil)®, 25–50 mg orally three times daily Drugs that deplete dopamine from nerve terminals, such as reserpine, 0.5–5 mg/d orally, or tetrabenazine 12.5–50 mg orally three times daily.

Warning!

The dopamine receptors blockers which used in treatment of chorea can cause by themselves chorea when creating supersensitive receptors for dopamine in BG as a result from excessive block caused by these drugs – an idiosyncratic side effect of them.

Sydenham's chorea

occurs in childhood asa post infectious complication of group A β-hemolytic streptococcal pharyngitis.A minor criterion of rheumatic fever (a late manifestation occur in 1/3 of patients with rheumatic fever).appears at least 3 months after the episode of ARFmore common in femalesself-limited disorder recover spontaneously within a few months.Due to autoimmune reaction affect caudate and STNAssociated with emotional liabilityTreatment includes short course of corticosteroids or intravenous immune globulin.ј of cases of will go on to develop chronic rheumatic valve disease.

Huntington Disease

an autosomal dominant disorder Prevalence about 5 per 100,000 population typically start between 30 and 50 years of age 10% of cases begin in childhood mean duration of illness is 20 years gradual onset and subsequent progression of chorea and dementia. Either abnormal movements or intellectual changes may be the initial symptom, but ultimately both are present. Bradykinesia and rigidity predominate in the juvenile-onset form (Westphal variant) . CT & MRI show atrophy of the cerebral cortex (dementia) and caudate nucleus (chorea). Decreased GABA & acetylcholine in BG Patient need genetic consoling to prevent transition of disease to subsequent generations Treatment is symptomatic

Hemiballismus

unilateral choreaInvolve one half of body (hemichorea)Violent & rapidthe proximal muscles of the limbs are involved. usually due vascular disease in the contralateral subthalamic nucleus: “usually chronic badly controlled HT or DM with subsequent lacunar infarction affect subthalamic nucleus”resolves spontaneously in the weeks following its onset. It is sometimes due to other types of structural diseasesin the past, it was an occasional complication of thalamotomy. Pharmacologic treatment is similar to that for chorea & frequently disappointing in cases due to vascular cause.The vascular induced type has no prognostic value

Athetosis

Involuntary slow writhing movement affect distal parts of limbs, in which the play of movement is very complex. Has similar causes & pathology to that of chorea. Frequently chorea & athetosis co-exist in the so called choreo-athetosis. Treatment: the same as for chorea.



Dystonia

Tardive Dyskinesia

develop after long-term treatment (at least 3 months) with antipsychotic (dopamine-receptor-antagonist) drugs or with metaclopramide.commonly encountered in chronically institutionalized psychiatric patients It’s risk increase with advancing ageCharacterized by abnormal choroe-athetoid movements being prominent about the face & mouth in adults while tend to be more obvious in the limbs in children.Mechanism of genesis is unknownDrug-induced supersensitivity of striatal dopamine receptors (old theory) is unlikely to be responsibleDecreased GABA in BG my underlies its genesisDiagnosis depend upon obtaining history of drug exposure. Otherwise it may be impossible to differentiate it from choreo-athetoid movements due to other causes It is easier to prevent than to cure (Antipsychotic drugs should be prescribed only on clear indication) Treating the established disorder by medications (like haloperidol, phenothiazines, reserpine or tetrabenazine) is generally unsatisfactoryOther therapeutic option is stopping the offending medication

Myoclonus

Myoclonus are sudden, rapid, brief shock like muscle contractions. Generalized myoclonus has a widespread distribution, focal or segmental myoclonus is restricted to a particular part of the body. Myoclonus can be spontaneous, or it can be brought on by sensory stimulation, arousal, or the initiation of movement (action myoclonus). Myoclonus may occur as a normal phenomenon (physiologic myoclonus) in healthy persons while falling asleep or on awaking from sleep, startle response & hiccup It can occur as an isolated abnormality (essential myoclonus),Could be a manifestation of epilepsy (epileptic myoclonus) like juvenile myoclonic epilepsy. It can also occur as a feature of a variety of degenerative diseases (like late stage of Alzheimer’s disease, Wilson disease, Huntington disease), infectious (like Creutzfeldt-Jakob disease, Subacute sclerosing panencephalitis, Viral encephalitis), and metabolic disorders (like Hypoglycemia, Hyperosmolar nonketotic hyperglycemia, Hyponatremia, Hepatic encephalopathy, Uremia, Hypoxia) (symptomatic myoclonus).Treatment by valproic acid, 250–500 mg orally three times daily, or clonazepam, 0.5 mg orally three times daily, gradually increased to as much as 12 mg/d.

Tics

sudden, recurrent, quick, coordinated stereotyped abnormal movements can be suppressed partially under volition of patient for short periods, although doing so may cause anxiety exaggerated by stress. common in children where usually benign & temporal (so claim the parents) & do not confused the case with focal motor seizure usually of psychiatrical significant Occur also in obsessive compulsive neurosis or obsessive compulsive states associated with Schizophrenia The syndrome of chronic multiple motor and vocal tics is generally referred to as Gilles de la Tourette syndrome. Usually started between ages 2 and 21 years. Most cases are sporadic. Dopaminergic excess in the brains of patients with Gilles de la Tourette syndrome has been postulated, mainly because of the beneficial effects that dopamine-blocking drugs like haloperidol can have on the tics. Clonidine ameliorate motor or vocal tics in roughly 50% of cases. It may act by reducing activity in noradrenergic neurons arising in the locus ceruleus.

Important Note! All involuntary movements disappear during sleep except epilepsy