Hyperkinetic movement disorder.pptx

ppt

1. Movement disorder phenomenology: Hyperkinetic disorders Presenter: Dr. Zeleke W/Y (NR-II) Moderator: Dr. Nebiyu B.(Consultant Neurologist)

2. Outline Anatomy Introduction to movement disorder Hyperkinetic movement disorder Tremor Chorea Myoclonus Tics Dystonia

3. Anatomy

4. Hyperkinetic movement Disorders

5. Introduction HMD's also referred to as Dyskinesias are characterized by abnormal, often repetitive, involuntary movements overlapped to normal motor activity. Its 5 major types are Tremors, Chorea, Dystonia, Myoclonus and Tics.

6. Etiology Common etiologies seen in Hyperkinetic Movement Disorders-[1] Genetic abnormalities Neurodegenerative diseases Structural lesions Infection Drugs Psychogenic problems Others

7. Pathophysiology There seems to be decrease in neural firing rates in the inhibitory output nuclei of the basal ganglia which results into a subsequent disinhibition of thalamocortical activity and sensory abnormalities might also have some role.

8. Hyperkinetic movement disorders can be grouped according to distinct cardinal features, which can be described in terms of: Time Space distribution Body state’s impact.

9. Rhythmicity A rhythmic movement repeats over time at a fixed interval of time. Regular rhythm :if the movement can be defined with a frequency during an observation period. e.g., essential tremor, parkinsonian tremor Irregular rhythm: if the movement repeats with a more complex temporal pattern. e.g. cortical myoclonus Arrhythmic : if the movement repeats over time at no fixed interval of time e.g., chorea, athetosis, ballism, tics, akathitic movements

10. Speed The second temporal item is the speed of the movement . It can be very fast, such as in myoclonus or hemifacial spasm, fast las in ballism or tics, intermediate as in chorea and tremors, or slow as in athetosis or akathitic movements.

11. TREMOR

12. Physiological Tremor The most common finding is a fine tremor in the outstretched limbs. It appears to originate in the heartbeat, mechanical properties of the limbs, firing of motoneurons, and synchronization of spindle feedback. Its frequency ranges from 7 to 12 Hz. It is usually noticeable only with electrophysiological recording. Amplitude is accentuated by fatigue, anxiety, fear, excitement, stimulant use, and medical conditions such as hyperthyroidism

13. Essential Tremor It is one of the most common movement disorders. Its prevalence increases with age. up to 10% of patients older than 60 years of age. Prevalence range between 0.01% and 20.5% It is a monosymptomatic illness characterized by gradually increasing-amplitude postural and kinetic tremor of the forearms and hands. There should not have triggers or other neurological signs.

14. Contd.... There is substantial heterogeneity and an overlap in some cases with dystonia and parkinsonism (50%).

15. Diagnostic criteria There is no pathological, biochemical, genetic, or other established and validated diagnostic criteria. Definition: isolated tremor syndrome of bilateral upper limb action tremor Duration at least 3 years’ with or without tremor in other locations. absence of other neurological signs, such as dystonia, ataxia, or parkinsonism. Positive family history and small doses of alcohol may improve the tremor.

16. Contd.... The Movement Disorders Society introduced term “ET-Plus,” a new tentatively and uncertainly defined entity characterized by the presence of additional neurological signs other than action tremor.

17. There seems to be a bimodal distribution for age at onset, peaking in the 2nd and 6th decade of life. The typical patient becomes aware of a barely perceptible postural or action tremor, usually in the distal arms and hands. The head and lower limbs are less commonly affected. Head tremor (titubation) is milder than limb tremor and is predomi- nantly of a side-to-side, “no-no” type. Head tremor is often associated with cervical dystonia and some patients with head tremor merely have dystonic tremor as a manifestation of their cervical dystonia without associated ET (Merola et al., 2019). Tremor of the face, trunk, and voice may also be present in patients with ET. The kinetic tremor is typically higher in amplitude than the postural tremor (Fig. 96.14). In contrast to PD where the handwriting is small, the handwriting in patients with ET is tremulous.

18. Parkinsonism

19. A striking improvement after ingestion of a small amount of ethanol is seen in 50% of patients and may be helpful in diagnosis (Mostile and Jankovic, 2010). Over time, the tremor worsens, causing increasing functional disability. Only a fraction of affected persons seek medical attention, and there is often a long latency from onset to presentation for care. At the time of diagnosis, nearly all patients with ET have significant social, functional, or occupational disabil- ity, and as many as 25% must make occupational adjustments as a result of tremor-related disability. ET is thought to be a monosymp- tomatic illness without changes in cognition, strength, coordination, or muscle tone, and the results of the neurological examination are usually normal. However, detailed studies of patients with ET have demonstrated frontostriatal cognitive deficits, changes in tandem gait, and other (albeit subtle) evidence of cerebellar dysfunction. The worsening of ET over time likely relates to two phenomena. First, the frequency of tremor in ET decreases over time, and its ampli- tude increases. This results from decreased attenuation of lower-fre- quency tremor secondary to age-related changes in the mechanical properties of limbs and muscle. A second possible contributor is true progression of the underlying disorder. According to recent studies, the severity of ET relates to disease duration independent of aging and age-related changes in mechanical properties of the muscles and limbs.

20. Etiology As many as two-thirds of patients give a positive family history of tremor, and first-degree relatives of patients with ET are 5–10 times more likely to have ET than first-degree relatives of control subjects. Direct questioning or examination of first-degree relatives increases the yield of family history to as high as 96%. In some families, pedi- gree analysis suggests ET is an autosomal dominant trait, with virtually complete penetrance by age 50 years. Twin studies suggest both hered- itary and environmental factors are important in disease expression. Hereditary ET is genetically heterogeneous, with several described loci including ETM1 (FET1) on chromosome 3, ETM2 on chromosome 2, a D 3 receptor gene (DRD3) localized on 3q13.3, and a locus on chromosome 6p23 (Kuhlenbäumer et al., 2014). One study involving a North American population demonstrated a significant association between a LINGO1 variant and ET, but further studies are needed before this association can be confirmed

21. Treatment The two most commonly used pharmacological treatments are β-adrenergic blockers and primidone. Propranolol total daily dose ranges from 120-320mg. Primidone: start with 25mg night time to max dose of 50-350mg Other options alprazolam, gabapentin, pregabalin,clonazepam, acetazolamide, and nimodipine. Botuninum toxin injection Thalamic DBS

22. CHOREA

23. Cortical Myoclonus The classification of cortical myoclonus implies that intrinsic cortical hyperexcitability is the major driver of the genesis of the patient’s myoclonus. The abnormally excessive motor cortical activity occurs at any one instant in a relatively small part of the motor homunculus. The excitation occurs in one part of the homunculus, then in another, usually correlating with a multifocal distribution of the myoclonus in the limbs.

24. However, excitability spread is common, subsequently activating adjacent muscles almost synchronously or even bilateral muscles bisynchronously when the discharge transmits through the corpus collosum. Myoclonus EMG discharges are brief (25 ms to 100 ms) in duration and usually spread to antagonist and other contiguous muscle groups

25. Contd.... Chronic posthypoxic myoclonus (Lance-Adams syndrome) is a well-known type of cortical myoclonus. Neurodegenerative illnesses that affects cortex, such asAlzheimer disease and dementia with Lewy bodies, commonly have cortical myoclonus. Certain drugs, such as lithium, will have myoclonus that is cortical.

26. Contd.... EEG may show epileptiform activity correlating with the myoclonic EMG discharges, either grossly or with back averaging. If this is demonstrated, cortical myoclonus is confirmed

27. Cortical-Subcortical Myoclonus This myoclonus physiology occurs with primary generalized seizures, such as myoclonic seizures in juvenile myoclonic epilepsy and myoclonus associated with absence seizures. Generalized spike-and-wave discharges on EEG that correlate with the myoclonus confirm this category of physiology. The abnormal excessive neuronal activity is spread between cortical and subcortical circuits, producing the diffuse excitation.

28. Contd.... As such, this physiology is dissimilar from localized cortical myoclonus and thus is in a different physiology category. Because this excitation over the sensorimotor cortex is simultaneously widespread, the myoclonus is commonly generalized. Myoclonus EMG discharges are brief (25 ms to 100 ms). Enlarged cortical waves in the somatosensory evoked potential can be seen but are not typical. Enhanced long-latency EMG reflexes are not associated with this physiology of myoclonus.

29. Subcortical/Nonsegmental Myoclonus Two major patterns are seen in subcortical/nonsegmental myoclonus. In the first pattern, the initial myoclonus EMG discharge corresponds to the subcortical nidus level (at the brainstem or spinal cord) followed by simultaneous rostral and caudal recruitment spread of muscle involvement. One example is brainstem reticular myoclonus in which the first discharge arises in the cranial nerve XI brainstem innervated muscles (trapezius and sternocleidomastoid)

30. Peripheral Myoclonus The term peripheral myoclonus should be reserved for instances where the movement phenotype is myoclonus,although it may coexist with other phenotypes as well. However, the distribution is defined by one or more peripheral nervous system elements (eg, root, nerve).

31. Myoclonus EMG discharges have a variable duration and appearance in a given muscle. The duration of these discharges may range from 50ms to 200 ms or longer. Often discharges are simultaneous or time locked between muscles in the same peripheral nerve distribution. Needle EMG may prove extremely useful in demonstrating the discharges within small muscles of the same peripheral nerve distribution as well as differential diagnosis of the movement itself (eg, myokymia).

32. The mechanism of peripheral myoclonus is controversial in many cases. Although association with a peripheral nervous system lesion is found, central reorganization of motor pathways may be a required event for peripheral myoclonus to occur. However, this is difficult to confirm

33. Segmental Myoclonus The myoclonus EMG discharges usually last longer than 100 ms and are highly rhythmic. By definition, the discharges are limited to a few contiguous segments of the brainstem or spinal cord. The discharges are either simultaneous with the other segments or at least time locked.

34. Contd..... The discharges are fairly persistent and not usually affected by stimuli or exogenous factors. Palatal segmental myoclonus is the most common location of segmental myoclonus. Palatal segmental myoclonus is divided into essential and symptomatic clinical types. Different types of focal lesions of the spinal cord can cause spinal segmental myoclonus.

35. Causes The classification scheme of Marsden and colleagues organizes the numerous etiologies of myoclonus into four major categories [1]: Physiologic Essential Epileptic Secondary (symptomatic)

36. Contd.... Each clinical category contains myoclonus arising from various etiologies and pathophysiologic mechanisms. Thus, differentiation by clinical-etiologic category is not always pure. In addition, a single etiology can produce different types of myoclonus, and occasional patients may demonstrate more than one type of myoclonus.

37. Physiologic myoclonus Physiologic myoclonus is a normal phenomenon that occurs in healthy people. There is minimal or no associated disability and the physical examination is typically without abnormality. The most familiar examples are jerks during sleep or sleep transitions. Others include anxiety-induced myoclonus, exercise-induced myoclonus, hiccups (singultus), and benign infantile myoclonus with feeding.

38. Contd.... Jerks associated with sleep — Varieties of sudden movement that occur during sleep or sleep transitions are: Partial myoclonic jerks are usually multifocal and occur in distal muscles. Massive myoclonic jerks are generalized and affect trunk and proximal muscles. Periodic limb movements of sleep (PLMS; nocturnal myoclonus)

39. Essential myoclonus the myoclonus is the most prominent or only clinical finding (ie, an "essential" phenomenon). The patient usually experiences some mild disability. Progression is slow or absent. Cognition is normal.

40. Contd.... Essential myoclonus is divided into sporadic and hereditary forms Sporadic (or idiopathic) essential myoclonus is a heterogeneous entity regarding distribution, exacerbating factors, and findings on neurologic examination. Some cases probably have false-negative family histories and actually represent hereditary disease.

41. Hereditary essential myoclonus Clinical characteristics: Onset typically before age 20 years Autosomal-dominant inheritance with variable expressivity A relatively benign course compatible with an active life and normal lifespan Absence of cerebellar ataxia, spasticity, dementia, and seizures

42. The myoclonus usually occurs throughout the arms and axial muscles. It is exacerbated by muscle activation and is markedly diminished with alcohol ingestion. Hereditary essential myoclonus demonstrates a subcortical-nonsegmental physiology

43. Epileptic myoclonus — Epileptic myoclonus refers to the presence of myoclonus in the setting of epilepsy (table 2). Seizures dominate the clinical picture in epileptic myoclonus. The etiology may be idiopathic, genetic, or a static encephalopathy

44. Myoclonus can occur as either one of several components of a seizure, the only seizure manifestation (myoclonic seizure), or one of multiple seizure types within an epileptic syndrome. Different types of epileptic myoclonus may demonstrate a cortical or cortical-subcortical physiology.

45. Fragments of epilepsy — "Fragments of epilepsy" designates myoclonic jerks in patients with epilepsy where myoclonus is not the main seizure phenotype and includes the following examples: Isolated epileptic myoclonic jerks Epilepsia partialis continua (focal status epilepticus) Idiopathic stimulus-sensitive myoclonus Photosensitive myoclonus Absences with a minor myoclonic component Epilepsy with myoclonic absences

46. Myoclonic epilepsy syndromes — Myoclonus is the main seizure phenotype associated with a number of epilepsy syndromes that mostly present in infancy or childhood (table 2): ●Infantile spasms (West syndrome) ●Severe myoclonic epilepsy of infancy (Dravet syndrome) ●Benign myoclonic epilepsy of infancy ●Lennox-Gastaut syndrome ●Myoclonic astatic epilepsy (Doose syndrome) ●Cryptogenic myoclonus epilepsy (Aicardi) ●Juvenile myoclonic epilepsy (JME; Janz syndrome) ●Familial cortical myoclonic tremor with epilepsy

47. Familial cortical myoclonic tremor with epilepsy — The term "familial cortical myoclonic tremor with epilepsy" encompasses a large number of syndrome labels (table 2) used to describe a genetically heterogeneous phenotype with the following core clinical features [48-51]: Autosomal-dominant inheritance Adult onset Distal action tremor and myoclonus Infrequent, secondarily generalized tonic-clonic seizures Relatively benign course, typically with normal cognition Responsiveness to anticonvulsants

48. Symptomatic myoclonus Myoclonus that occurs as a secondary symptom of a neurologic or nonneurologic disorder has been traditionally termed "symptomatic."

49. Contd.... Major categories include the following: Drug-induced and toxic syndromes Encephalopathies, including hypoxia Neurodegenerative diseases Focal nervous system damage Progressive myoclonic epilepsy Progressive myoclonus ataxia Infectious and postinfectious disorders

50. Autoimmune inflammatory disorders, including opsoclonus-myoclonus syndrome Metabolic disorders Disorders that affect multiple organ systems, including mitochondrial disorders Storage diseases Exaggerated startle syndromes Psychogenic jerks

51. EVALUATION Guidelines for the evaluation of a patient with myoclonus may be conceptualized into four parts: ●Syndrome identification based upon clinical features ●Ancillary laboratory testing ●Clinical neurophysiology ●Testing for rare causes of myoclonus

52. TICS

53. DYSTONIA

54. Reference Bradyley 2020 Continuum