Pediatric Movement Disorders - Ataxia

Etiology

There are many diseases that may lead to ataxia. Determining which disease is the cause for a particular child's ataxia may be very difficult and requires a careful series of steps planned by an experienced physician. Often, the diagnosis cannot be made immediately, but must await careful examination of the progression or resolution of symptoms over time. In some cases, however, it is important to make the diagnosis rapidly so that treatment may be started before further damage occurs.

Static (fixed) injury:
Ataxic cerebral palsy, stroke, trauma, hypoxic injury

Neoplastic/Paraneoplastic:
Tumors of the cerebellum or brainstem, neuroblastoma in the chest or abdomen (associated with the myoclonus-opsoclonus-ataxia syndrome)

Degenerative/Demyelinating:
Ataxia-telangiectasia; ataxia oculomotor apraxia; Friedreich's ataxia; Wilson's disease; spinocerebellar ataxia (including Machado-Joseph disease); dentato-rubro-pallido-luysian atrophy (DRPLA); olivopontocerebellar atrophy (OPCA); Marinesco-Sjögren syndrome; multiple sclerosis; Pelizaeus-Merzbacher disease; Angelman syndrome

Chemical/metabolic:
Hartnup's disease; lipidoses, mitochondrial disorders (e.g., Leigh's disease, MERRF, and pyruvate dehydrogenase complex deficiency); glutaric aciduria; Refsum's disease; vitamin deficiency (e.g., B12, E, thiamine); abetalipoproteinemia (Bassen-Kornzweig disease); lysosomal diseases (e.g., Krabbe's disease, metachromatic leukodystrophy, carnitine acetyltransferase deficiencies, juvenile Gaucher's disease, Tay-Sachs disease, Niemann-Pick type C); ceroid lipofuscinosis; carbohydrate-deficient glycoprotein syndromes (congenital disorders of glycosylation-CDG); biotinidase deficiency; holocarboxylase deficiency

Malformations:
Joubert syndrome; Dandy-Walker malformation; basilar impression; vermian agenesis; cerebellar dysgenesis; rhombencephalosynapsis; Chiari malformation (types 2 and 3); pontocerebellar hypoplasia

Drug-induced:
Anti-epileptic medications (particularly phenytoin and carbamazepine); antihistamines; barbiturates; lithium; alcohol; chemotherapy; heavy metal poisoning (e.g., lead, mercury, thallium); bromide intoxication

Acute/Paroxysmal:
Acute cerebellar ataxia (acute symptoms are usually due to a virus or frequently following varicella infection); dominant familial episodic ataxias (type 1 lasts 10 to100 minutes, is associated with myokymia and chorea, and treated with acetazolamide or phenytoin; type 2 lasts for 1 to 24 hours, starts during adolescence, may worsen during the child's lifetime, and is treated with acetazolamide or flunarizine); calcium "channelopathies"; metabolic disease (e.g., propionic acidemia, maple-syrup urine disease and its thiamine-responsive variant, urea cycle disorders); porphyria; electrolyte or glucose abnormalities; Miller-Fisher variant of Guillain-Barré syndrome; basilar migraine

Disorders that mimic ataxia:
Weakness; hypothyroidism; low blood pressure; any peripheral neuropathy (with lack of sensation in the feet); astasia-abasia (usually psychogenic); seizures ("pseudo-ataxia"); paroxysmal vertigo (associated with migraines); myoclonus; tremor