Ataxia

Exam Cram

• Ataxia is an examination sign of the nervous system characterised by a lack of co-ordination

• Presentation: poor balance & falls, nystagmus & broad based unsteady gait,

• Classification: localise to vestibular system, cerebellum or proprioceptive sensory tracts

• Management: as per underlying cause, MDT, 

Ataxia

Physiology

Co-ordination requires the integration of: 

• Vestibular inner ear inputs

• Proprioception peripheral nerve inputs

• Cerebellum integration

• Motor execution

Cerebellar Ataxia

• Cerebellar impairment

• Aetiology: Alcohol, Nutritional (Vitamin E), lesion- MS, Stroke, Malignancy

• Presentation: DANISH + broad based gait

Sensory Ataxia

• Impairment of peripheral nerves of proprioception

• Aetiology: 

  • Peripherally- Peripheral Neuropathy,

  • Spinal Disease: Myelopathy- Subacute Combined Degeneration of Spinal Cord, disc prolapse

• Presentation: loss of vibration/ proprioception, rhomberg's +ve

Vestibular Ataxia

• Impairment of inner ear vestibular system

• Aetiology: BPPV, Vestibular Neuronitis, Vestibular Schwannoma

• Presentation: vertigo, horizontal nystagmus

Cerebellar Syndrome

Presentation: 

Ipsilateral to lesion (unilateral)

DANISH

• Dysdiadchokinesia

• Ataxia

• Nystagmus- horizonal,

• Intention Tremor

• Staccato Speech

• Hypotonia, pendulum reflexes

Additional signs

• Dysmetria- past pointing

• Broad based gait

Aetiology

• Systemic

  • Alcohol - can have sensory peripheral neuropathy

  • Phenytoin, lithium

  • Vitamin E deficiency

  • Hypothyroidism

• UMN lesions

  • Space Occupying lesion- malignancy (paraneoplastic), abscess

  • Vascular- infarct, bleed

  • MS

• Genetic: Friedreich's Ataxia

Localising the lesion

Unilateral= ipsilateral cerebellar lesion (cerebellar hemispheres)

Bilateral 

• Genetic: Freideich's ataxia

• Acquired: Alcohol, Drugs, Vitamin E deficiency, Hypothyroidism

• Midline cerebellar lesions (vermis)

• Multiple lesions: disseminated malignancy, MS, multiple infarcts

Fast impulse of nystagmus towards cerebellar side of lesion

Investigations

Baseline

• FBC, U&Es, CRP, LFTs

• ECG +- CXR

• B12, folate, TFT, CMP, Mg

• ANA, protein electrophoresis, HIV, syphillis, Lyme Disease

CT-H 

MRI-Head

Written in 2026