Movement disorders

Movement disorders Dr.Zana A. Mohammed M.B.Ch.B, F.I.B.M.S. NEUROLOGY SCHOOL OF MEDICINE UNIVERSITY OF SULAIMANIAH

Essential tremor • Essential tremor, the most common movement disorder, is a syndrome of unknown etiology • characterized by a slowly progressive postural and/or kinetic tremor, usually affecting both upper extremities. • Essential tremor is familial in at least 50-70% of cases. Transmission is AD, with incomplete penetrance. • Some cases are sporadic with unknown etiology.

Clinical presentation • Essential tremor generally is considered to be monosymptomatic (tremor only), although some patients have abnormalities in gait and balance. • The tremor is characteristically postural (occurring with voluntary maintenance of a position against gravity) and kinetic (occurring during voluntary movement). • A family history of essential tremor is noted in 50-70% of cases

Tremor usually begins in one upper extremity and soon affects the other; essential tremor rarely extends from the upper extremity to the ipsilateral leg • A mild degree of asymmetry is not unusual • In about 30% of cases, tremor involves the cranial musculature; the head is involved most frequently, followed by voice, jaw, and face

The amplitude of the tremor is highly variable, depending on the state of emotional activation; tremor amplitude is worsened by emotion, hunger, fatigue, and temperature extremes • A degree of voluntary control is typical, and the tremor may be suppressed by skilled manual tasks

Tremor may be intermittent initially, emerging only during periods of emotional activation • Over time the tremor becomes persistent • The tremor resolves during sleep • Ethanol intake temporarily reduces tremor amplitude in an estimated 50-70% of cases • It usually resolves when the body part relaxes.

Other characteristics of essential tremor include the following: • Both upper extremities are typically affected • Mild asymmetry is not uncommon • Tremor also may affect the head, voice, and lips • Tone and reflexes are normal • Parkinsonian features such as bradykinesia and rigidity are absent

Diagnosis • Essential tremor is usually diagnosed based on family history and examination findings; thus, laboratory and imaging studies are usually not required. • Head (CT) scanning and magnetic (MRI) findings are normal in essential tremor.

If the patient’s family history and examination findings are not indicative of essential tremor, consider the following laboratory studies: • Standard electrolyte panel • Thyroid function tests • Blood urea nitrogen and creatinine levels • Liver function tests • Serum ceruloplasmin (for Wilson disease)

Treatment • Primidone and propranolol are the cornerstones of maintenance medical therapy for essential tremor. These reduce tremor amplitude in approximately 50-70% of patients. • Some patients require only intermittent tremor reduction (eg, to attend a meeting or engage in a social activity). • they may take propranolol (10-40 mg) approximately one half hour prior to the event.

Parkinson’s disease • Parkinsonism is a progressive degenerative, extra pyramidal disorder of muscle movement, due to dysfunction in basal ganglia, comprising four cardinal features:- • Brady kinesia or hypo kinesia. • Muscle rigidity. • Resting tremor. • Impairment of postural balance leading to disturbances of gait, and falling. The secondary manifestations are mask-like face, difficulty in speech, slowing of mental process and dementia.

PD – Impairment of Postural Balance Prone to falling

Parkinsonism (PD) - signs

The classical syndrome: • Tremors • Rigidity • Bradykinesia • These may be absent initially, when non-specific symptoms of tiredness, aching limbs, mental slowness, depression & small handwriting (micrographia) may be noticed. • Although parkinsonian features are initially unilateral, gradual bilateral involvement is the rule. A resting tremor in an upper limb being a common presenting feature.

Tremor • Resting tremor, may remain the predominant symptom for some years. • i with activity, h tremor when… • Walking • Anxious Resting 4-6 Hz • Usually first in fingers/thumb, may also affect the legs, mouth & tongue. • Coarse, complex movements, flexion/extension of fingers • Abduction/adduction of thumb • Supination/pronation of forearm • May affect arms, legs, feet, jaw, tongue • Intermittent, present at rest & when distracted • Diminished on action Postural 8-10 Hz • Less obvious, faster, finer amplitude • Present on action or posture, persists with movement

Rigidity • Cogwheel type, mostly upper limbs -Rigidity with superimposed tremor, felt as tigthness/stiffness of muscles, Ratchet-like (catch-release-catch release like movement. • Plastic (lead pipe) type, mostly legs • Stiffness • Neck • Trunk • Shoulders • Posture • Head bowed • Body bent forward • Arms flexed • Thumbs turned into palms • Knees bent (slightly)

Bradykinesia • Slowed ability to start and continue movements, and impaired ability to adjust the body's position. • The word bradykinesia is = slow movement • Akinesia=Loss of movement Especially face Expressionless face(poker/masked-face) • Slow speech-softer & indistinct Dysphonia • Dysphagia Drooling • Slowness in initiating or repeating movements -Most have difficulty with rapid fine movements, as slowness of gait &difficulty with tasks as fastening buttons, shaving or writing (micrographia).

Abnormal Gait/posture • Asymmetrical Gait • Slow to start walking • Shortened stride • Stiff legged gait-rigidity comes through on one side, therefore difficult clearing swinging on one side • Rapid, small steps, tendency to run (festination) • Reduced arm swing (usually unilateral) • Impaired balance on turning • Leads with head and shoulders • Fall forward down turned posture-Postural righting reflexes are impaired early, but falls tend not to occur until later.

Additional features • Muscle strength / reflexes remain normal, plantar responses are flexor. • There is a paucity of facial expression (hypomimia) & the blink reflex may be exaggerated & fail to habituate (glabellar tap sign). • Sensation is normal & intellectual abilities are not affected initially. • As the disease progresses, 1/3 develop cognitive impairment. • PD commonly associated with other features; loss of smell, depression, dementia, autonomic dysfunction, sleep disturbance- due to involvement of other non-dopaminergic structures as disease progresses.

Etiology • The degeneration of neurons occurs in substantia nigra pars compacta and the nigrostriatal tract that are dopaminergic and inhibit the activity of striatal GABA ergic neurons. This results in deficiency of dopamine in striatum which controls muscle tone and coordinates movements. • Nerve fibers from cerebral cortex and thalamus secrete acetylcholine in the neostriatum causing excitatory effects that initiate and regulate gross intentional movements of the body. • In Parkinson’s disease, due to deficiency of dopamine in striatum, an imbalance between dopaminergic (inhibitory) and cholinergic (excitatory) system occurs, leading to excessive excitatory actions of cholinergic neurons on striatal GABA ergic neurons.

Pathophysiology Degeneration of neurons in the substantia nigra pars compacta Degeneration of nigrostriatal (dopaminergic) tract Results in deficiency of Dopamine in Striatum - >80%

Pathophysiology • Imbalance primarily between the excitatory neurotransmitter Acetylcholine and inhibitory neurotransmitter Dopamine in the Basal Ganglia DA ACh

Strategy of Treatment • In Parkinson’s disease dopaminergic inhibitory activity is reduced and cholinergic excitatory activity is increased. Therefore, therapy is aimed at restoring dopamine in the basal ganglia and antagonizing the excitatory effects of cholinergic neurons. Salvador Dali- Spanish artist

Treatment of PD

Drugs used for Parkinsonian Disease: • Drug therapy is aimed at restoring the balance between the dopaminergic and cholinergic components, which is achieved by: • Increasing the central dopaminergic activity OR • Decreasing the central cholinergic activity OR BOTH. Hitler and Franco

Drugs which increase dopaminergic activity. • Drugs that replace dopamine (Dopamine precursor): • Levodopa • Dopa-decarboxylase inhibitors (Drugs which increase the central availability of Levodopa) • Carbidopa, Benserazide. They act in the periphery as they do not enter brain . Lahore Medical & Dental College

Dopamine agonist like bromocriptine and pramipexol • Drugs which increase release or inhibit reuptake of dopamine (also called dopamine facilitator) like Amantadine. • MAO-B inhibitor (selegnine) prevent dopamine breakdown

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Movement disorders