Chorea
-Definition: Brief, irregular, unpredictable, semi-purposeful brief jerky movements that flit from one
part of body to the other.
-Can see parakinesia (semipurposeful camouflage), motor impersistance (darting tongue, milkmaid
grip), pendular reflexes.
-NOT repetitive and no sense of abnormal muscle contractions (unlike dystonia); no urge to perform
the movements (unlike tics)
-Levodopa-induced dyskinesias are indistinguishable clinically from chorea; history of levodopa
exposure is how you tell them apart.
Etiologies:
1) Inherited:
A) Autosomal dominant: HD ,HDL1, HDL2, HDL3, DRPLA, benign hereditary chorea, SCA 1, 2, 3, 17,
C9orf72
B) Autosomal recessive: Neuroacanthocytosis , NBIA , pantothenate kinase associated
neurodegeneration (PKAN), neuroferritinopathy aceruloplasminemia infantile neuroaxonal dystrophy,
Wilson disease, Ataxia-telangiectasia, ataxia with oculomotor apraxia (types 1 and 2), Dystoniaataxia-pyramidal (OPA3).
C) Maternal: Mitochondrial disorders
2) Sporadic/acquired:
A) Autoimmune: Rheumatic/sydenham chorea, chorea gravidarum, SLE, polyarteritis nodosa,
Behcet’s, antiphospholipid, paraneoplastic.
B) Electrolyte/metabolic/toxins: hypo/hypernatremia, hypocalcemia, hypo/hyperglycemia, renal failure,
liver failure/hyperammonemia, hypoparathyroid, hyperthyroid, CO, mercury/heavy metals, B12
deficiency, polycythemia vera.
C) Infectious/inflammatory: HIV, encephalitis, syphilis.
D) Drugs (neuroleptics, antiemetics, dopamine, anticonvulsants, steroids, OCP, tardive).
E) Vascular: Infarcts, static encephalopathy
D) Degenerative: CJD
Pearls from the history:
-Acute onset: Vascular or sydenham’s
-Chronically progressive: neurodegenerative
-Nonprogressive: benign hereditary chorea
-Episodic: paroxysmal hyperkinetic chorea (genetic)
Workup for acquired/sporadic chorea:
-Comprehensive acquired chorea labs: COMP, CBC, TSH, PTH, pregnancy test, ANA, ESR/CRP,
B12, HIV, CPK (chorea-acanthocytosis, Mcleod), ferritin (neuroferritinopathy if low), ceruloplasmin
(wilsons), 24 hour urine copper, lactate/pyruvate (mitochondrial), AFP (ataxia telecangectasia, ataxia
with oculomotor apraxia), antigliadin (celiac), uric acid (Lesch-Nyhan), peripheral blood smear,
DSDNA, ENA-5, antiphospholipid antibodies, urine and serum organic and amino acids, RPR,
ammonia, heavy metals. +/- paraneoplastic panel (anti-YO, anti-Hu, anti-CRMP5), CJD workup.
-MRI, CT C/A/P vs. PET scan (? occult malignancy)
Workup for genetic chorea:
Examples:
-HL2: South African families. Onset 3-4th decade. Chorea, dementia, parkinsonism, dystonia, death
in 15-25 years.
-DRPLA: Average age onset 30 (but ranges 1st-7th), looks like HD but with severe ataxia,
parkinsonism. AD.
-Neuroacanthocytosis: AR. Onset 20-40 years. Tongue pushing food out of mouth (oro-buccal lingual
dyskinesias), self-mutilation, seizures, absent reflexes, vocalizations, dystonia, tics, elevated
CPK/LFTs, peripheral neuropathy/myopathy. Slow chorea. Sudden loss of axial muscle tone (“rubber
man”). Diagnosis by finding acanthocytes. EMG will show neuropathy. PET shows pre-synaptic and
post-synaptic dopamine deficit.
-Benign hereditary chorea: AD. Starts in early childhood, then static in 2 nd decade. No dementia, but
can get learning problems/MR, thyroid problems, lung problems. Often in Brain-Lung-Thyroid
syndrome.
-C9orf72 expansion: Dystonia, chorea, myoclonus, tremor, rigidity.
-PKAN: X-linked, get brain iron accumulation. Global developmental delay/epilepsy/spasticity in
childhood, followed by dystonia, chorea, cognitive decline, parkinsonism. MRI shows EYE OF THE
TIGER sign.
Tx:
-Treat underlying cause
-Tetrabenazine (depletes dopamine)
-Antipsychotics
-Antiepileptics (Valproic acid, carbamazepine)
-? DBS