myoclonus
Jump to navigation
Jump to search
Etiology
- hypoxia, anoxia
- lipid storage disease
- encephalitis, viral encephalitis
- myelitis
- metabolic encephalopathy due to
- respiratory failure (post-hypoxic myoclonus)
- chronic renal failure, uremia
- hepatic failure, asterixis
- electrolyte imbalance
- toxic serotonin syndrome
- neurodegenerative disease
- paraneoplastic disorders
- tetanus
- seizures, epilepsy
- sleep states
- nerve compression[2]
- pharmaceuticals
- occasionally normal action
Pathology
- sustained myoclonus generally indicates upper motor neuron disease
Clinical manifestations
- very brief, involuntary, random muscle contracture & relaxation in rapid succession
- shock-like, jerky movements[3]
- brief lapses in muscle tone may result in loss of balance[3]
- may occur spontaneously at rest, in response to sensory stimuli, or with voluntary movements
- may involve a single muscle unit or a group of muscles
Differential diagnosis
- dystonia: twisting & posturing, no lapses in muscle tone
Management
- agents of choice
- valproate (Depakote)
- clonazepam
- levetiracetam
- zonisamide
- topiramate[2] 2 Alternative agents
- phenobarbital
- baclofen
More general terms
More specific terms
- myoclonic dystonia; alcohol-responsive dystonia; dystonia-11
- myoclonic seizure
- nocturnal myoclonus (periodic limb movement disorder, PLMD, periodic limb movements of sleep, PLMS)
- posthypoxic myoclonus (Lance-Adams syndrome)
Additional terms
References
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 122
- ↑ 2.0 2.1 2.2 Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2012, 2015, 2018, 2021
Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022 - ↑ 3.0 3.1 3.2 Mills K, Mari Z. An update and review of the treatment of myoclonus. Curr Neurol Neurosci Rep. 2015 Jan;15(1):512. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/25398378
- ↑ National Institute of Neurological Disorders and Stroke (NINDS) NINDS Myoclonus Information Page https://www.ninds.nih.gov/Disorders/All-Disorders/Myoclonus-Information-Page