Assessment of ataxia

Ischaemic stroke

Cerebellar strokes can result in increased intracranial pressure because of attendant oedema over the course of a few days. Close monitoring of patients for increasing lethargy and signs of brain stem compression is needed, preferably in an intensive care unit (ICU) setting. Occasionally, ventricular drainage or urgent decompression of the posterior fossa can be life-saving.

Additionally, both cerebellar strokes and brain stem strokes that initially present with ataxia may develop additional and sometimes life-threatening problems related to extension of the stroke. Recognition of this with judicious monitoring and use of various forms of anticoagulation and thrombolysis are important.[107]National Institute for Health and Care Excellence. Stroke and transient ischaemic attack in over 16s: diagnosis and initial management. April 2022 [internet publication]. https://www.nice.org.uk/guidance/NG128 Some patients with posterior circulation strokes may have non-specific symptoms, such as dizziness indistinguishable from more common vestibular pathologies. Ataxia can be distinguished from a vestibular problem by the presence of vertigo and oscillopsia. Hearing loss and tinnitus are more typically associated with lesions in cranial nerve 8 or the vestibular apparatus.

A direction-changing nystagmus and subtle skew deviation that can be detected by the "cover" test may be clinical indicators of a brain stem infarct, rather than a vestibular lesion.

Magnetic resonance imaging scans with appropriate diffusion-weighted sequences can detect small acute ischaemic lesions and should be obtained when in doubt.

Cerebellar haemorrhage

Can result in increased pressure in the posterior fossa with both upward transtentorial herniation and downward tonsillar herniation. These are life-threatening and may need ventriculostomy and urgent decompression.

Acute cerebellitis

Oedema and raised pressure in the posterior fossa is a rare complication of acute cerebellitis in children. Children in whom oedema is detected or who develop signs of such (e.g., lethargy) require ICU monitoring and may need ventriculostomy and decompression of the posterior fossa.

Miller-Fisher syndrome

This is a variant of Guillain-Barre syndrome and can soon evolve to affect the muscles of swallowing, as well as respiratory and limb muscles. These patients need close monitoring of their respiratory function. Prophylactic placement in the ICU and even elective intubation may be indicated. Guillain-Barre syndrome is also associated with autonomic dysfunction such as arrhythmia, and warrants cardiac telemetry.

Wernicke-Korsakoff syndrome

This is usually seen in people with a history of alcohol dependence with nutritional deficiency, although other causes of nutritional deprivation, such as gastric pathology, may be present. Patients have rapid onset of a confusional state with an amnestic problem (problem forming new memories, often associated with confabulation), nystagmus, oculomotor palsies, and ataxia. This needs to be recognised urgently and treated with high-dose parenteral vitamin B1 in addition to general nutritional support.

Acute intoxication

Many cerebellotoxic drugs can cause acute ataxia, as can alcohol inebriation. Careful drug history and serum drug levels (if appropriate) are diagnostic, and management usually involves discontinuing the offending drug.