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ataxia; dyssynergia
A disorder in which muscles fail to move in a coordinated fashion. (also see balance disorder)
Etiology:
1) acute onset:
- stroke involving cerebellum, brainstem &/or thalamus
- toxin or medication-induced
2) subacute onset
- multiple sclerosis
- Miller-Fisher variant of Guillain-Barre syndrome
- hydrocephalus
- posterior fossa mass effect (tumor, abscess)
- paraneoplastic disorder
- thiamine deficiency
- toxins
3) inherited degenerative disorders
- Friedreich's ataxia
- spinocerebellar atrophy
- Machado-Joseph disease
- ataxia with vitamin E deficiency
4) systemic disorders
a) metabolic disorders
- mitochondrial disorders
- abnormal amino acid metabolism
- abnormal organic acid metabolism
- urea cycle defects
- vitamin & cofactor deficiencies
- enzyme deficiencies
- hexosaminidase deficiency
- gamma-glutamyl cysteine synthetase deficiency
- glutamate dehydrogenase deficiency
- disorders of lipid metabolism
- abetalipoproteinemia & hypobetalipoproteinemia
- Refsum's disease
- cerebrotendinous xanthomatosis
- hypothyroidism (rare, reversible)
b) DNA repair disorders
- ataxia telangiectasia
- xeroderma pigmentosum
c) inflammatory autoimmune disorders
- paraneoplastic cerebellar degeneration
- multiple sclerosis
d) infections
5) sensory ataxia
6) cerebellar ataxia
7) spinocerebellar ataxia
8) miscellaneous disorders
- post-hyperthermia
- post anoxia
- hydrocephalus: normal pressure hydrocephalus
Pathology:
- most adult-onset chronic ataxia syndromes involve cerebellar degeneration [3]
Physical examination:
- tandem walk
- finger-to-nose
- rapid-alternating movements
- heel-to-shin
- inability to tap two objects 12 inches (30 cm) apart 32 times in 15 seconds (90% sensitivity, 90% specificity)
Clinical manifestations:
1) staggering, wide-based gait
2) patients may not be able to stand with feet together & eyes open
Laboratory:
1) serum vitamin levels
a) serum vitamin B12
b) serum vitamin E
c) serum thiamine
2) thyroid function studies
3) cerebrospinal fluid (CSF) analysis
4) serology
a) Lyme disease serology
b) Legionella serology
5) genetic analysis
Radiology:
- MRI neuroimaging
- cerebellar & brainstem atrophy generally seen with with adult-onset chronic ataxia syndromes [3]
Management:
1) No proven therapies for spinocerebellar ataxias (SCA) 1-5
2) Identify treatable disorders
a) malignancies
b) vitamin deficiencies
c) drug & alcohol toxicity
d) infections
e) hypothyroidism
f) metabolic disorders
Related
balance disorder
Specific
Brown-Marie syndrome
cerebellar ataxia (cerebellar syndrome, cerebellar dysmetria)
gait ataxia
sensory ataxia
spinocerebellar ataxia (SCA)
truncal ataxia
General
movement disorder
sign/symptom
References
- Harrison's Principles of Internal Medicine, 13th ed.
Companion Handbook, Isselbacher et al (eds), McGraw-Hill
Inc. NY, 1995, pg 2284-85
- Harrison's Principles of Internal Medicine, 14th ed.
Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 2263-67
- Medical Knowledge Self Assessment Program (MKSAP) 16
American College of Physicians, Philadelphia 2012