Movement Disorders0 Movement disorders (MDs) typically result from abnormalities of the extrapyramidal system.0 The core structures of the extrapyramidal system include the caudate nucleus, globus pallidus, substantia nigra, red nucleus, thalamic nucleus, subthalamic nucleus and their connections to the cerebral cortex, brain stem, and cerebellum, with the final output being pyramidal tract.0 The main transmitter substances are dopamine, acetylcholine, GABA and glutamate.0 MDs can be hyperkinetic, hypokinetic, or dyskinetic.
Pattern Recognition0 Tremor: rhythmic involuntary oscillating of a body part. Usually involves distal extremities. Tremor is subclassified according to position of the limb (rest, action, intention, postural).0 Chorea: rapid, continuous, irregular, brief, purposeless movements, often involve distal limb.0 Athetosis: slow, irregular undulating, writhing-type movement, often associated with chorea.0 Tics: stereotyped, irregular simple or complex movements.0 Dystonia: sustained, abnormal contraction of a group of muscles, resulting in abnormal posture of the limb.
0 • Ballismus: violent, flinging movements often involving proximal limb, usually unilateral (hemiballismus), but can be bilateral lower or upper extremities because of contralateral subthalamic nucleus lesion.0 • Myoclonus: sudden, irregular shock-like contraction of the muscle or group of muscles.0 • Tardive dyskinesia: stereotyped movements often involving the facial and oral muscles, manifesting as tongue protrusion, chewing, lip smacking, and facial grimacing. The trunk and extremities are often also involved. This condition is seen after chronic use of dopamine-blocking antipsychotic or antiemetic drugs.0 • Rigidity: increased muscle tone throughout the passive range of motion of the limb. When there is coexistence of tremor, the examiner detects a ratchet like resistance, referred to as “cogwheel rigidity.”
1. Rest tremor.0 Tremor that occurs in a body part that is not voluntarily activated and is completely supported against gravity.0 Rest tremor increases with mental stress (counting backwards), or when movements of another body part are performed (especially walking). It is mostly found in Parkinsons disease, but also in other parkinsonian syndromes, including drug-induced parkinsonism.0 Its presence indicates dysfunction of the nigrostriatal dopamine pathway or its efferent projections to basal ganglia thalamocortical circuits.
2. Action tremor.0 Postural tremor. Tremor present while voluntarily maintaining a position against gravity. This tremor is usually documented by having the patient outstretch the arms.0 Simple-kinetic tremor. Tremor that occurs during voluntary action that is not target-directed.0 Intention tremor. Action tremor in which amplitude increases substantially during the pursuit of a target or goal. Its presence suggests a disturbance of the cerebellum or its afferent/efferent pathways.0 Task-specific kinetic tremor. Tremor occurring during specific activities, such as the primary writing tremor and occupational tremors. These tremors are often associated with dystonia.
Treatment (ET)a) β-Blockers: propranolol (Inderal) studied most extensivelyi) Inderal LA (long-acting) may be started at 40 mg daily, and increased in small increments tooptimal doses 240-320 mg/day, as tolerated and if neededii) Tremor reduction up to 60%iii) Contraindicated if asthma, diabetes mellitus, marked bradycardia, second- or third-degreeatrioventricular block, heart failureb) Primidone (Mysoline)i) As effective as propranolol but more adverse effectsii) Converted to phenylethylmalonamide and phenobarbital, the latter with longer half-lifeiii) To minimize the adverse effects, start with small doses of 50 mg/day and with subsequenttitration, may be divided as 3-times-daily regimeniv) May be titrated up to maximum of 750 mg/day (250 mg 3 times daily)c) Second-line agents: carbonic anhydrase inhibitors(e.g., methazolamide), gabapentin, benzodiazepinesd) Surgical treatmenti) Thalamotomyii) Thalamic stimulation: high success rate (tremor reduced in up to 90% and abolished in 50%of cases); bilateral procedures have lower complication rates than thalamotomy
Chorea0 a. Unsustained, nonstereotypic movements with variable speed and direction, may be rapid or brief, may flow from one extremity to the next.0 b. Choreoathetosis: chorea occurring concurrently with athetosis or dystonic movements0 c. Ballismus (ballism): large-amplitude random movements, most prominent at the proximal limbs0 d. Hemichorea or hemiballismus: refers to hemi body distribution of the movement disorder
Clinical featuresa. Mild chorea may appear as restlessness or uneasymovementsb. Parakinesia: chorea that may seem semipurposeful andmay “blend into” purposeful movementsc. Inability to maintain tone: maintaining handgrip(“milkmaid’s grip”) or maintaining protrusion of tongue(“flycatcher’s tongue”)
Treatment and managementa) Dopamine receptor blockers and dopamine-depleting agents forchorea, psychosis, and behavioral symptomsi) Typical antipsychotics are not well tolerated and can induce tardive dyskinesiasii) Atypical antipsychotics better tolerated and do not induce tardive dyskinesiasiii) Atypical antipsychotic—clozapine: effective for psychosis but not for chorea;disadvantage is high cost and risk of agranulocytosisiv) Atypical antipsychotic—olanzapine: effective for both chorea and psychiatricsymptoms (may increase stroke risk in elderly)b) Riluzole: corticostriatal glutamate release inhibitor; may potentially improvechoreac) Remacemide: glutamate/NMDA receptor antagonist, may marginally improvechorea .d) Coenzyme Q10: mitochondrial complex I enhancer, possible decline inmeasure of disability (not statistically significant), possible benefit on behavioralsymptomse) Anticonvulsants (e.g., valproate): may be helpful for chorea and psychiatricand behavioral symptoms, including aggression and irritability
Dystonia0 syndrome of sustained muscle contractions producing abnormal postures or repetitive movements involving different distributions0Classification according to distribution:1) Focal: one body region2) Multifocal: at least two noncontiguous body regions3) Hemidystonia: at least two ipsilateral body regions4) Segmental: adjacent body regions5) Generalized: involvement of both lower extremities or onelower extremity and trunk and another body region
0 A characteristic feature of dystonic movements is that they may be diminished by sensory tricks such as gently touching the affected body part (geste antagoniste).0 Dystonic movements tend to be exacerbated by fatigue, stress, and emotional states and may be suppressed by relaxation and sleep.0 Dystonia typically worsens during voluntary movement. At the time of onset, dystonia may only be present during a specific movement (action dystonia).0 With progression, however, the dystonia may emerge with other movements and eventually may be present at rest.
Causes1) Idiopathic torsion dystonia is a primary dystonia and mayoccur as a familial condition. The spectrum of the disorder isbroad and includes focal (blepharospasm, torticollis,spasmodic dysphonia, writers cramp), segmental, andgeneralized forms. The gene for the autosomal dominantfamilial form has been located on chromosome 9q,2) Secondary causes of dystonia include metabolic disorders(e.g., Wilsons disease) degenerative diseases (parkinsonsdisease, progressive supranuclear palsy, corticobasalganglionic degeneration, Huntingtons disease, multiplesystem atrophy), and nondegenerative central nervoussystem disorders (anoxia, head or peripheral trauma, priorstroke, multiple sclerosis, or drug-induced)
Treatment1)Botulinum toxin A (BTX)2) Medical treatment0 a) Dopaminergic (Sinemet)0 b) Dopaminergic antagonists0 c) Dopamine-depleting agents0 d) Anticholinergic (e.g., trihexyphenidyl, benztropine): may be effective in up to 40% of patients0 e) Baclofen: may be effective in up to 20%0 f) Clonazepam: may be effective in up to 15%0 g) Anticonvulsants (e.g., carbamazepine, gabapentin)3) Surgical treatment0 a) Peripheral denervation procedures: bilateral anterior cervical rhizotomy, microvascular decompression, ramisectomy, peripheral nerve lysis, myectomy0 b) Deep brain stimulation0 c) Unilateral thalamotomy
ACUTE DRUG-INDUCED DYSTONIAAcute drug-induced dystonia presents with abnormaltongue or jaw postures and neck dystonia, occurringwithin the first 3 days of starting a neuroleptic.The treatment is benzotropin (Cogentin), 2 mgintravenously or intramuscularly, or 50 mgdiphentrydramine (Benadryl) intravenously.
0 Myoclonus is a sudden Iightning-like movement produced by abrupt and brief muscle contraction.0 The four etiologic categories are essential, physiological, epileptic, and symptomatic.0 Essential myoclonus is a non physiological variety that occurs in isolation without evidence of other neurologic symptoms or signs. It may occur in familial and sporadic forms. Some patients may note a striking improvement with small quantities of alcohol.
Treatment:0 clonazepam and other benzodiazepines, valproate, 5- hydroxytryptophan, piracetam
0 Tics are abrupt, stereotyped, coordinated movements or vocalizations. They may vary in intensity and be repeated at irregular intervals. Tics may be exacerbated by stress and relieved by distraction.0 Tics may be motor or vocal and are classified as being either simple or complex. Examples of simple motor tics include eye blinking, shoulder shrugging, and toe curling. Spitting and finger cracking are examples of complex motor tics. Simple vocal tics may take the form of sniffing, throat clearing, snorting, or coughing.0 Complex phonic tics are meaningful syllables, words, or phrases (“okay,” “shut up”), and include palilalia (repeating the last syllables of ones words), echolalia (repeating someone elses words0 Sensory tics are uncomfortable sensations (pressure, cold, warmth, or paresthesias) localized to certain body parts that are relieved by the performance of an intentional act in the affected area.
0 Tics may also be classified as idiopathic (the majority) or secondary. Secondary causes include head trauma, encephalitis, stroke, and various drugs.0 For treatment of tics, dopamine antagonists (haloperidol or the atypical antipsychotics) are most effective; however, because of the adverse effect profile of these agents, less potent drugs such as clonazepam and clonidine should be tried first
Q.1. A 45-year-old man with frequent but vaguegastrointestinal complaints has been doing well on acombination of added fiber, ranitidine, and metoclopramide.He has no new complaints. He appears to be chewinggum, but examination reveals nothing in his mouth, and hedoes not appear to be able to suppress the movements. Heis unaware of the movements, but his spouse noted theirprogressive appearance during the past six months. Themost likely cause of his problem isA. Whipple’s diseaseB. Chronic oral tic disorderC. Drug-induced tardive dyskinesiaD. Normal aging
Q.2. An 86-year-old woman with Alzheimer’s disease has beenusing donepezil for her ailing memory. Risperidone was addedrecently for progressively agitated behaviors. Several monthslater, she appears slow and has had several falls.Examination reveals a shuffling gait, stooped posture, and slowedmovements. Otherwise, her examination is unchanged.Appropriate management includesA. Starting levodopa/carbidopa for possible Parkinson’s diseaseB. Starting an antidepressant for suspected depressionC. Discontinuing risperidoneD. Discontinuing donepezil