MYOCLONUS

PRESENTED BY MATTHEW EBRIGHT PGY-2

MYOCLONUS - OUTLINE

Definition

Pathophysiology

Classification

Etiologies

Specific Examples

Evaluation

Treatment

Videos

DEFINE MYOCLONUS

What is it?

• Rapid• Brief• Involuntary• Contraction• One or multiple muscles, around a joint• Symmetry?• Synchrony?

Differential Diagnosis?

PATHOPHYSIOLOGY

Not entirely clear!

• Reduced intracortical inhibition• Hyper-excitable sensorimotor cortex• Cerebellar degeneration• Striatal lesions

HOW TO CLASSIFY MYOCLONUS

1. Anatomic localization

2. Time course

3. Triggers

4. Other general clinical features

HOW TO CLASSIFY MYOCLONUS

1. Anatomic localization

2. Time course

3. Triggers

4. Other general clinical features

LOCALIZATION

Is it…

• Focal• Segmental• Multi-focal• Diffuse/generalized

LOCALIZATION

Cortical

• Diffuse vs focal• Sensorimotor cortex

Subcortical

• Cortical-subcortical and subcortical-nonsegmental

Segmental

• Brainstem• Spine

HOW TO CLASSIFY MYOCLONUS

1. Anatomic localization

2. Time course

3. Triggers

4. Other general clinical features

TIME COURSE

Non-progressive

• Spinal, benign rolandic epilepsy, JME, post-hypoxic, iatrogenic, metabolic

Progressive

• Neurodegenerative, epilepsia partialis continua

Rapid onset or progression

• CJD, SSPE, post-infectious, anti-NMDA, metabolic, psychogenic

HOW TO CLASSIFY MYOCLONUS

1. Anatomic localization

2. Time course

3. Triggers

4. Other general clinical features

TRIGGERS

1. Spontaneous

2. Action-induced

3. Sensory-induced

HOW TO CLASSIFY MYOCLONUS

1. Anatomic localization

2. Time course

3. Triggers

4. Other general clinical features

CLINICAL GROUPING

Primary Secondary

PRIMARY MYOCLONUS• Physiologic

• Essential/hereditary

• Myoclonus-dystonia syndrome

• Hyperekplexia

• Epileptic

• EPC, benign rolandic epilepsy, juvenile myoclonic epilepsy, familial cortical tremor with epilepsy

• Primary progressive myoclonus of aging

SECONDARY MYOCLONUS• Progressive myoclonic encephalopathies and storage

diseases

• Lafora body• MERRF• Lipofuscinosis• Unverricht disease• Ramsay Hunt• Krabbe• Tay Sachs• Sandhoff• Sialidosis (cherry-red spot myoclonus)• Gaucher type III• Dentatorubrual-pallidoluysian atrophy

SECONDARY MYOCLONUS• Neurodegenerative diseases

• Alzheimer dementia• Parkinson disease• Dementia with Lewy bodies• Corticobasal degeneration• Multiple system atrophy• Frontotemporal dementia

SECONDARY MYOCLONUS• Infectious/Inflammatory

• Encephalitis (NMDA encephalitis)• Post-infectious• SSPE• Opsoclonus-myoclonus syndrome

SECONDARY MYOCLONUS• Metabolic

• Liver, renal, dialysis, sodium, glucose, Celiac, Whipples• Drugs/Toxins

• Anti-convulsants, anti-psychotics, anesthetics, morphine, levodopa, contrast, heavy metals

• Nervous System Damage

• Post-hypoxic, traumatic, stroke, spinal cord lesions, demyelinating disease

• Psychogenic

SPECIFIC EXAMPLES• Myoclonus-dystonia

• Syndrome of essential myoclonus• Action-induced multifocal myoclonus• Cervical dystonia or writer’s cramp• Autosomal dominant• Alcohol-responsive

SPECIFIC EXAMPLES• Post-Hypoxic Myoclonus (Lance-Adams Syndrome)

• Subcortical, multifocal• Action-induced, exquisitely• Days to weeks after recovery

SPECIFIC EXAMPLES• Neurodegenerative Diseases

• PD – levodopa, amantadine, severe late disease• Corticobasal degeneration – action induced and stimulus

sensitive• MSA – low-amplitude, irregular, arrhythmic, hands and

fingers, face• LBD• CJD – aggressive, progressively multifocal

SPECIFIC EXAMPLES• Opsoclonus-myoclonus ataxia syndrome

• Chaotic myoclonic eye movements• Oscillopsia• Multifocal, action-related myoclonus• Paraneoplastic or post-infectious

SPECIFIC EXAMPLES• Hyperekplexia

• Autosomal dominant• Stiff babies• Episodic tonic spasms• Nocturnal myoclonus• Exaggerated startle responses

• Brainstem localization• Non-habituating• Overly-sensitive to stimuli• May persist through life

SPECIFIC EXAMPLES• Canine myoclonus

• Distemper - RNA virus• Multi-system disease• Encephalomyelitis• Myoclonus, seizures, rapid neurodegeneration

EVALUATION• Localize!

• Labs, CSF?

• Imaging

• EMG

• EEG-EMG

TREATMENT

EXAMPLE VIDEOS

Opsoclonus-Myoclonus - https://www.youtube.com/watch?v=zX4j0IsFbAk

Propriospinal Myoclonus - https://www.youtube.com/watch?v=W15D8N0wlyY

Generalized Myoclonus in SSPE - https://www.youtube.com/watch?v=pfCQP7IL2XY

Myoclonic Dystonia - http://wolterskluwer.http.internapcdn.net/wolterskluwer_vitalstream_com/MP4s/permalink/cont/a/cont_19_5_2013_08_08_zadikoff_190510_sdc3.mp4

Post-hypoxic Myoclonus (Lance-Adams) - http://wolterskluwer.http.internapcdn.net/wolterskluwer_vitalstream_com/MP4s/permalink/cont/a/cont_19_5_2013_08_08_espay_190510_sdc4.mp4

Amantadine-induced - http://wolterskluwer.http.internapcdn.net/wolterskluwer_vitalstream_com/MP4s/permalink/cont/a/cont_19_5_2013_08_08_espay_190510_sdc6.mp4 and http://wolterskluwer.http.internapcdn.net/wolterskluwer_vitalstream_com/MP4s/permalink/cont/a/cont_19_5_2013_08_08_espay_190510_sdc7.mp4

VIDEOSCorticobasal Degeneration - http://wolterskluwer.http.internapcdn.net/wolterskluwer_vitalstream_com/MP4s/permalink/cont/a/cont_19_5_2013_08_08_duker_190510_sdc11.mp4

Unverricht-Lundborg - http://wolterskluwer.http.internapcdn.net/wolterskluwer_vitalstream_com/MP4s/permalink/cont/a/cont_19_5_2013_08_08_morgante_190510_sdc12.mp4

Hyperekplexia - http://www.dailymail.co.uk/health/article-2767882/The-father-s-literally-scared-STIFF-time-s-startled-sudden-noise-taken-surprise.html

Focal Cortical Myoclonus - https://www.youtube.com/watch?v=BHeCok19jWo

Palatal Myoclonus –

https://www.youtube.com/watch?v=GlnxI93PrMM

Canine Myoclonus – https://www.youtube.com/watch?v=MHQhoH5gYWo

IN SUMMARY

Myoclonus:

- History

- Exam

- Localize

- Time course

- Clinical features

- Diagnostics

- Treat

- Neurology all in one special!