MOVEMENT DISORDERS

Parkinsonism

• Parkinsonism - symptom complex manifest by bradykinesia with rigidity and/or tremor

• damage to different components of the basal ganglia - striatum (putamen and caudate nucleus), subthalamic nucleus (STN), globus pallidus pars externa (GPe), globus pallidus pars interna (GPi), and the SNc

Differential Diagnosis of Parkinsonism

• Parkinson's Disease - most common

Atypical Parkinsonisms

• Multiple-system atrophy

• Progressive supranuclear palsy

• Corticobasal ganglionic degeneration

Secondary Parkinsonism

• Drug-induced

• Tumor

• Infection

• Vascular

• Normal-pressure hydrocephalus

• Trauma

• Liver failure

• Toxins (e.g., carbon monoxide, manganese, MPTP, cyanide, hexane, methanol, carbon disulfide)

Parkinson's Disease

Cardinal Features

• Bradykinesia

• Rest tremor

• Rigidity

• Gait disturbance/postural instability

• Pathological hallmark - degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc),

Hyperkinetic Movement Disorders

Tremor

• alternating contractions of agonist and antagonist muscles in an oscillating, rhythmic manne

• an be most prominent at rest (rest tremor), on assuming a posture (postural tremor), or on actively reaching for a target (kinetic tremor)

CAUSES

• Enhanced physiological tremor

• essential tremor - postural

• Parkinsonian tremor - resting

• dystonic tremor

• cerebellar (‘intention’) tremor - kinetic

• drug-induced tremor

Chorea and athetosis (choreoathetosis)

• Chorea - irregular, brief, jerky, unrepetitive, unintentional movements, affecting differing parts randomly

• Athetosis - slower, more writhing movements than chorea

• The two often coexist

CAUSES

• Rheumatic – SYDENHAM’S CHOREA/St. VITUS’ DANCE

• H.D

• Pregnancy – chorea gravidarum

• Neuroacanthocytosis

• NBIA

• Vascular disorders

• Hypo/hyperglycemia

• Systemic lupus erythematosus is the most common systemic disorder that causes chorea

• Hyperthyroidism

• autoimmune disorders including Sjögren's syndrome

• infectious disorders including HIV disease

• metabolic alterations

• polycythemia rubra vera

• medications (especially anticonvulsants, cocaine, CNS stimulants, estrogens, lithium)

Hemiballismus

• violent form of chorea composed of wild, flinging, large-amplitude movements on one side of the body

• Proximal limb muscles tend to be predominantly affected

• most common cause is a partial lesion (infarct or hemorrhage) in the subthalamic nucleus (STN)

Myoclonus

• brief, rapid (<100 ms) shock-like, jerky movement consisting of single or repetitive muscle discharges

• focal, multifocal, segmental, or generalized

• Seen in hypoxemic damage (especially following cardiac arrest), encephalopathy, neurodegeneration, metabolic disturbances (renal failure, electrolyte imbalance, hypocalcemia), toxins

Dystonia

• sustained or repetitive involuntary muscle contractions frequently associated with twisting or repetitive movements and abnormal postures