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Extrapyramidal Disorders.pptx
- 1. MOVEMENT DISORDERS Sisay GizawGeberemichael, M.D Addis Ababa University, School of Medicine, Department of Neurology Year -III Introductory Lecture
- 2. LECTURE OBJECTIVES 1) Illustratebasal ganglia anatomy 2) Overview of basal ganglia dysfunction 3) Overview of common diseases of basal ganglia
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- 4. Basal ganglia anatomy… •What do you understand by the terms pyramidal, extrapyramidal & basal ganglia? • Motor systems: 1. Pyramidal (primary motor cortex) 2. Non-pyramidal • Basal ganglia • Cerebellum • Others (brainstem nuclei, etc…) Subcortical motor systems
- 5. Basal ganglia anatomy… •Components of basal ganglia (or nuclei): 1. Caudate 2. Putamen 3. Globus pallidus (GP) • Interna (GPi) & externa (GPe) 4. Substantia nigra • Pars compacta (SNc) & reticularis (SNr) 5. Subthalamic nucleus (STN) 6. Other (not important): nucleus accumbens etc… neostriatum Lentiform nucleus Corpus striatum
- 7. 3. Globus pallidus 1.Caudate nucleus (head) 2. Putamen 1 2 3 1 2 3 Thalamus Internal capsule
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- 10. Extrapyramidal dysfunctions… MOTOR LOOPS: •Cortex • Subcortex • Cortex • Spinal cord Cerebral cortex cerebellum Spinal cord Basal ganglia Feedback 1. Muscles 2. Sensory
- 11. Prefrontal Other cortical areas M1 M2 Caudate & putamen VLo DistalLimbs "Basal Ganglia Motor Loop" VlLo =Ventrolateral nucleus, oralis (thalamus) M1=Primary motor cortex M2= supplementary motor cortex Substantia nigra Glutamate (+) Dopamine (+/-)
- 12. Caudate & putamen Subthalamic nucleus Thalamus Globus pallidus externa(GPe) Globus pallidus interna (GPi) Caudate & putamen Cortex Globus pallidus interna (GPi) GABA (-) GABA(-) GABA(-) GABA Glutamate (+) Glutamate (+) Direct loop: excitatory Pathways from the striatum to the thalamus Indirect loop: inhibitory Dopamine(-)
- 13. Prefrontal PPC M1 M2 Cerebellum Pons VLc Distal Limbs "Lateral Cerebellar MotorLoop" VLc=Vetrolteral nucleus, caudalis (thalamus)
- 14. Extrapyramidal dysfunctions… Functions: • Basalganglia – Motor • Selection/ initiation • Control slow mov't • Tone-posture – Non-motor: • Emotion, cognition & oculomotor function • Cerebellum – Motor • Coordinate • Learning • Tone-posture – Non-motor
- 15. Extrapyramidal dysfunctions… • Effectsof dysfunction in general: 1. Involuntary (excessive) movement 2. Altered movement (poverty of movement) a. Slow b. Interrupted c. Uncoordinated 3. Altered posture & tone 4. Non-motor features Hyperkinetic movement disorders Hypokinetic movement disorders
- 17. Extrapyramidal dysfunctions… • Parkinsonism: –Causes: • Idiopathic PD • Neurodegenerative disorders • Secondary parkinsonism – Combinations of: • Tremor (resting) • Bradykinesia • Rigidity • Postural instability
- 18. Extrapyramidal dysfunctions… • Tremor: –Rhythmic & oscillatory mov't of body part, constant frequency & variable amplitude – Static • Rest: parkinsonism & rubral • Postural : physiological, essential & neuropathic – Kinetic • Action: physiological & essential • Intention: cerebellar & rubral – Psychogenic
- 19. Extrapyramidal dysfunctions… • Chorea: –Causes: • Developmental/aging • Hereditary • Secondary – Drugs, toxins, metabolic, infectious etc… – Continuous, unsustained, rapid, abrupt, and random muscle contraction • Hypotonia may occur
- 20. Extrapyramidal dysfunctions… • Athetosis: –Continuous, sinuous & nonpatterned writhing mov't ('slow chorea'), mainly due to cerebral palsy • "Without fixed position” • Ballismus: – Sever, coarse chorea, usually unilateral • Hemi- or biballismus – Lesion of contralateral subthalamic nucleus & adjacent structures (stroke usually)
- 21. Extrapyramidal dysfunctions… • Dystonia: –Causes: • Primary • Secondary • Psychogenic – Repetitive, patterned, twisting & sustained mov't (slow athetotic or rapid) • Focal • Segmental • Generalized
- 22. Extrapyramidal dysfunctions… • Myoclonus: –Simple brief jerk-like mov't, not coordinated or suppressible • Segmental • Generalized – Causes: • Physiological • Pathological – Essential – Epileptic – Symptomatic – Seg 6.flv
- 23. Extrapyramidal dysfunctions… • Tics: –Sudden, brief intermittent mov't (motor tics) or utterance (vocal ticks) • Cease during sleep & partially suppressible – Causes: • Physiological (mannerism) • Primary (transient or persistent) • Secondary – Drugs, autoimmune/ postinfectious, etc…. – Seg 7.flv
- 24. Extrapyramidal dysfunctions… • Diagnosticevaluation: – History – Physical examination – Laboratory studies • Routine • Optional
- 25. COMMON DISEASES OFTHE BASAL GANGLIA (MOVEMENT DISORDERS)
- 26. ….diseases of basalganglia • Common movement disorders: – Parkinson's disease (PD) – Essential tremor (ET) – Sydenham chorea (SC) – Tardive dyskinesia (TD)
- 27. ….diseases of basalganglia • Parkinson's disease – Archetype of hypokinetic movement disorders • 1-2% of population over 50yrs • M: F=1:1 • Median age=57yr (rare <50yrs) – Motor features • Hypokinesia, rigidity, tremor, gait & postural disturbances – Non-motor features • Autonomic, sleep disorders, psychiatric & cognitive abnormalities
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- 29. Parkinson's disease pathophysiology (nigrostriatalneurons death) Cortex (SMA) Putamen/caudate Substantia nigra (SNc) VLo(thalamus) Subthalamic nucleus Globus pallidus (GPi) + Glu + Glu + D + Glu + Glu _ GABA _ GABA X Dopaminergic < cholinergic effect
- 30. ….diseases of basalganglia • Diagnosis – Clinical (rarely neuroimaging required) • PD treatment: – Medical (pharmacological) – Surgical (pallidoectomy, deep brain stimulation) – Tissue transplant
- 31. ….diseases of basalganglia • Essential tremor (ET) – Most common neurological cause of postural or action tremor (up to 5% of population) • Peak age 2nd and 6th decades • M=F • Familial tremor (AD) or sporadic (benign ET) – Neuropathological basis: • Brainstem and cerebellar lesions?? • Increased risk for PD and dementia ?
- 32. ….diseases of basalganglia • ET diagnostic criteria: – Bilateral action tremor of hands & forearms (4-10Hz) • Chronic disorder (>3yrs) • Beneficial response to alcohol – No neurological signs except cogwheel rigidity – Positive family history (>50%) • Treatment: – Medical (propranolol & primidone) and surgical (DBS & thalamotomy)
- 33. ….diseases of basalganglia • Sydenham chorea (SC) – One of the major clinical criteria of ARF (in 18-36%) • 1-8months after group A streptococcal pharyngitis (often purely) – Commonest acquired chorea in childhood, F:M 2:1 • Insidious onset of chorea, emotional lability & hypotonia • Elevated anti-DNAse B & ASO antibodies • Exclusion of other causes of chorea • ARF= acute rheumatic fever
- 34. ….diseases of basalganglia • Reversible abnormalities of the striatum – Improves gradually, mean duration of 12 to 15 wks (occasionally ≥2yrs) – Recurence rate 20-30% • SC treatment: – Valproate, phenobarbital, haloperidol & diazepam (± prednisone) – Benzathin penicillin prophylaxis
- 35. • Tardive dyskinesia(TD) – Diagnosis of TD • Occurrence of involuntary movements – Variable mixture of orofacial dyskinesia (athetosis, chorea, tics and facial grimacing ) and dystonia • History of ≥1 month of dopamine receptor blocking agents (antipsychotic drugs and metoclopramide) use • Exclusion of other causes of abnormal movements – Dopamine receptor supersensitivity ± structural cellular alterations in the brain
- 36. • TD treatment: –DC or change offending drug • Often reversible (50-90%) within several months – Pharmacologic treatments • Benzodiazepines, botulinum toxin or anticholinergics – Resume antipsychotic drugs • Suppress TD (in treatment-resistant) – DBS (in unresponsive)
- 37. Summary • Extrapyramidal disordersdon't cause weakness • Diagnosis of movement disorders is essentially clinical • Underlying cause of movement disorders can be identified with focused work-up • Treatment of movement disorders requires working knowledge of basal ganglia neurobiochemisty