surat tanprawate, md, frcp division of neurology

8/14/2019 Surat Tanprawate, MD, FRCP Division of Neurology

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MyoclonusMyoclonus

is a clinical sign defined as sudden,brief, shocklike, involuntarymovements caused by muscular contractions or inhibitions


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MyoclonusMy

oclonus

Sudden, brief, shock like involuntary jerks caused bycontraction or inhibition of one muscle or multiple muscle, irregular in rhythm and amplitudes

ClonusClonus

A series of rhythmic, uniphasic or monophasic (unidirectional) contraction andrelaxation of a group of muscles


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Hammond Hammond Convulsive tremor Convulsive tremor

FriedreichFriedreichParamyoklonus multipleParamyoklonus multiple


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PolymyoclonusPoly

myoclonus

Widespread,lightninglike, arrhythmic

contraction

MuscularMuscularcontractionscontractions

Positive myoclonus

MyoclonusMy

oclonussimplexsimp

lex

Single or are repeatedin a restricted groupof muscle

MM uscularuscular ii nhibitionsnhibitions

Negative myoclonus or

asterixis


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CC lassifilassifi cationcationEtiologies Physiological Essential Epileptic Symptomatic

Anatomicdistribution

Focal Segmental Multifocal Generalize

Provocative factor Spontaneous Reflex Action

Contraction pattern Rhythmic Arrhythmic Oscillatory

Clinicalneurophysiology testing

Cortical Cortical-subcortical Subcortical-supraspinal Spinal peripheral


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Where is the lesion?

Physiologic classificationWhat is the lesion? Etiologic classification


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Physiologic classificationPhysiologic classification

CorticalSubcortical : Thalamus, Brain stem

Spinal :Segmental,

PropriospinalPeripheral


Contractio

n pattern

Provicativ

e factor


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EtiologicEtiologicclassificat classificat

ionion


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ClassificationClassification


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Guideline for assessment of a patient withGuideline for assessment of a patient withmyoclonusmyoclonus

Physiologic classification: Hx, PE

Basic ancillary testing

Clinical neurophysiology testing to determinephysiological classification

Advanced neurophysiology for rareand specific diagnosis

Etiologies


Provocative factor

Contraction pattern


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Cortical myoclonusCortical myoclonus

Arising from the sensorimotorcortexConduct rapidly in the pyramidaltractsMost common type of myoclonusRostral to caudal distribution


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Cortical myoclonusCortical myoclonusTypeType CharacteristicCharacteristic PhysiologicPhysiologic

studystudySpontaneous corticalmyoclonus

Cortical reflex myoclonus

Epilepsia partialiscontinuae.g.PME

Lance Adam syndromeEncephalopathyStorage diseaseInfection: CJD, HIVDegeneration: CBD

Arrhythmic pattern

Focal or multi-focal jerk

Biggest hand , face

Spontaneous or induceby reflex or action

Giant SEP

EEG discharge


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Subcortical myoclonusSubcortical myoclonus

Spread either rostral or caudalfrom the brainstemAxial and bilateral movement


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Subcortical myoclonusSubcortical myoclonusOriginOrigin CharacteristicCharacteristic Physiologic studyPhysiologic study

Thalamus

Brain stem-Hyperexplexia-Reticular reflexmyoclonus-Palatal myoclonuse.g.HypoxiaMetabolic: renal, hepaticLymes diseaseNon-dopa responsiveparkinsonismPontine demyelinatinglesion

Asterixis in arm

Generalize and axial

Very stimulussensitive


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Spinal myoclonusSpinal myoclonus

Typically associated with a focallesion, with little spread of myoclonicactivity from spinal-generator sitesLesion may directly damage the cord changes in the afferent signaling from

peripheral and supraspinal structure

Rostral or caudal spread from thespinal cord level


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Spinal myoclonusSpinal myoclonusTypeType CharacteristicCharacteristic Physiologic studySegmental

Propriospinal

Rhythmic, notstimulus sensitive,limited bycontiguoussegment of cord

Rhythmic or notUsually thoracciclevelRecruit axial m. viaslowly conductionpolysynapticpropriospinalpathwayMore extensive

Typical: slow,bilateral of flex m.of trunk or lower

Long durationelectromyographic

burst that speed slowup and down


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Cause TumorInfectionIdiopathic

SyringomyeliaIschemic myelopathy


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Peripheral myoclonusPeripheral myoclonus

By alter sensory input and inducecentral reorganization withabnormal spinal sensory afferencecausing loss of inhibitory spinalinterneuron


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Peripheral myoclonusPeripheral myoclonusCharacteristicCharacteristic

Trauma

Nerve entrapment

Hemifacial spasm

Not stimulussensitive

Arrhythmic jerk

Persist during sleep


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Focal, SegmentalCortical, Spinal ,Peripheral

Rhythmic provocative

cortical +/- +

subcortical +/- ++

spinal + -

peripheral - -

Multifocal, GeneralizeCortical, subcortical


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Etiologic diagnosisEtiologic diagnosis

Physiologic

classification Cortical Subcortical

Spinal

Peripheral

Etiologicdiagnosis Physiologic Essential Epileptic

myoclonus Symptomatic


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Part 1Part 1 :: Anatomic distribution patternAnatomic distribution pattern(History, physical examination)(History, physical examination)

Full historymode of myoclonusonsetpresence of otherneurological problemshistory of seizurescurrent and past drugor toxin exposurepast or currentmedical problemsfamily history

Physical examinationDistribution (may be focal,segmental, multifocal, hemi,generalised)

Temporal profile (includesrhythmic or irregular)ContinuousIntermittent (sporadic or trains)Activation profileRest (spontaneous myoclonus)Voluntary movement (actionmyoclonus)Reflex stimuli (any combinationof touch, light, sound, musclestretch)


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Physiologic classificationPhysiologic classification

Lancet Neurol 2004; 3: 598607


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Classification of myoclonusClassification of myoclonusI. Physiological

myoclonus (healthyindividuals)

Sleep jerks (eg, hypnic jerks) Anxiety induced Exercise induced Hiccough (singultus)

Benign infantilemyoclonus withfeeding

II. Essentialmyoclonus(primarysymptom, non-progressivehistory) Hereditary

(autosomaldominant) Sporadic

p ep c myoc onus se zuresp ep c myoc onus se zures


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Fragments of epilepsy Isolated epileptic myoclonic jerks Epilepsia partialis continua Idiopathic stimulus-sensitive myoclonus Photosensitive myoclonus Myoclonic absences in petit mal epilepsy

Childhood myoclonic epilepsy Infantile spasms Myoclonic astatic epilepsy (Lennox-Gastaut) Cryptogenic myoclonus epilepsy (Aicardi) Awakening myoclonus epilepsy of Janz (juvenile myoclonic

epilepsy)Benign familial myoclonic epilepsy (Rabot)Progressive myoclonus epilepsy: Balticmyoclonus (Unverricht- Lundborg)

. p ep c myoc onus se zures. p ep c myoc onus se zuresdominate, part of chronic seizuredominate, part of chronic seizure

disorder)disorder)


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IV. Symptomatic myoclonus (secondary,progressive, or static encephalopathy

dominates)Storage disease

Lafora body disease GM2 gangliosidosis (late infantile, juvenile) Tay-Sachs disease Gauchers disease (non-infantile

neuronopathic form) Krabbes leucodystrophy Ceroid-lipofuscinosis (Batten) Sialidosis (cherry-red spot) (types 1 and 2)

Spinocerebellar degenerations Ramsay-Hunt syndrome Friedreichs ataxia Ataxia-telangiectasia

Other spinocerebellardegenerations

Basal ganglia degenerations Wilsons disease Torsion dystonia Hallervorden-Spatz disease Progressive supranuclear palsy Huntingtons disease Parkinsons disease Multisystem atrophy Corticobasal degeneration Dentatorubropallidoluysian atrophy

Dementias Creutzfeldt-Jakob disease Alzheimers disease

Dementia with Lewy bodies Frontotemporal dementia Retts syndrome


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Infectious or post-infectious

Subacute sclerosing panencephalitis Encephalitis lethargica Arbovirus encephalitis Herpes simplex encephalitis Human T-lympnotropic virus IHIV Post-infectious encephalitis Miscellaneous bacteria

(streptococcus, clostridium, other)

Malaria

Syphilis Cryptococcus Lyme disease Progressive multifocal

leucoencephalopathy

Metabolic Hyperthyroidism Hepatic failure Renal failure Dialysis syndrome Hyponatraemia Hypoglycaemia

Non-ketotic hyperglycaemia Multiple carboxylasedeficiency

Biotin deficiency Mitochondrial dysfunction Hypoxia Metabolic alkalosis

Vitamin E deficiency


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Toxic and drug-inducedsyndromes

Physicalencephalopathies Post-hypoxia (Lance-

Adams) Post-traumatic Heat stroke Electric shock Decompression injury

Focal nervous systemdamage

CNSPost-strokePost-thalamotomy

Tumour TraumaInflammation (eg, multiplesclerosis)Moebius syndromeDevelopmentalIdiopathic

Peripheral nervous system TraumaHaematoma


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Malabsorption Coeliac disease Whipples disease

Eosinophilia-myalgiasyndrome

ParaneoplasticencephalopathiesOpsoclonus-myoclonussyndrome

Idiopathic Paraneoplastic

Infectious Other

Exaggerated startlesyndrome Hereditary Sporadic

Hashimotosencephalopathy

Multiple systemdegenerations

Allgrove syndrome DiGeorge syndrome Membraneous lipodystrophy

Unknown Familial Sporadic


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Part 2:Part 2:

Basic ancillary testingBasic ancillary testingElectrolytes (+/- including bismuth)GlucoseRenal function tests

Hepatic function testsParaneoplastic antibodiesDrug and toxin screen (if history suggests)Brain imaging

ElectroencephalographySpine imaging (if focal or segmental) Thyroid antibodies and function

P 3


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Part 3:Part 3: Clinical neurophysiology testing toClinical neurophysiology testing to

determine physiological classificationdetermine physiological classification


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Part 4:Part 4:Advanced testing for rare and specificAdvanced testing for rare and specific

diagnosesdiagnosesBody imaging for occultcancerCerebrospinal fluid exam(for infectious andinflammatory disorders, 14-3-3 protein for Creutzfeld- Jakob disease)

Tests for malabsorptiondisorders (eg, coeliac sprue,Whipples disease)Enzyme assays fordeficiency(eg,neuraminidase,biotinidase)Copper studies for Wilsonsdisease

Tissue biopsy of skin orleucocytes (eg, Lafora bodies,ceroid inclusions,etc.)Alpha-feto protein, cytogeneticanalysis, radiosensitivty of DNA

synthesis (ataxia-telangiectasia)Genetic testing for inheriteddisorders (eg, EPM1 gene,mitochondria genes, huntingtingene, etc)Mitochondria function studies(lactate, muscle biopsy, etc.)


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surat tanprawate, md, frcp division of neurology

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