Cerebellar osce

Question 1

Causes of cerebellar disease?

Answer 1

• Stroke
• Tumour
• MS
• Congenital (eg. Arnold Chiari)
• Friedreich’s ataxia
• Alcohol abuse
• Thiamine deficiency (eg. Wernicke’s encephalopathy)
• Anti-epileptic medication

Question 2

Signs of cerebellar lesion (DANISH)

Answer 2

• Dysdiadochokinesis
• Ataxia (limb I trunk)
• Nystagmus
• Intention tremor
• Speech (slurred, staccato)
• Hypotonia

Question 3

Localising the cerebellar lesion

Answer 3

• This may be impossible Clinically
• Lesions may involve both the vermis and hemispheres
• Central (vermis) lesion symptoms tend to cause Truncal ataxia sitting & standing
o Poor heel-toe
o Slurred staccato speech

• Cerebellar hemisphere lesion symptoms tend to cause
o lpsilateral limb ataxia (dysmetria, intention tremor, dysdiadochokinesis)
o Nystagmus
o Unsteady gait, falling towards side of lesion when walking

Question 4

Ddx of Nystagmus

Answer 4

• Congenital
o Pendular nystagmus
o Can occur in any direction
o Most marked in neutral position

• Vestibular (apparatus, nerve or pathways - eg.
labyrinthitis, Meniere’s, syringobulbia, MS)
o Unidirectional jerk nystagmus
o Fast phases away from side of lesion
o Nystagmus increases when eyes look in the direction of the fast phase, away from side of lesion (Alexander’s law)

• Central (brainstem or cerebellar vermis)
o Bidirectional jerk nystagmus
o Direction of fast phase varies with direction of gaze

• Unilateral cerebellar hemisphere lesion
o Nystagmus when looking in direction of lesion
o Fast phase towards lesion

Question 5

Ddx of Dysarthria

Answer 5

• Facial nerve palsy (CN VII) - look for facial weakness
• Bulbar palsy - look for flaccid, wasted, fasiculating tongue
o MND
o Guillain Barre
o Syringobul bia

• Pseudobulbar palsy - look for spastic, contracted tongue
o MND
o MS
o Bilateral stroke (eg. internal capsule)

• Myasthenia gravis
• Cerebellar disease [See above]

Question 6

Wernicke’s encephalopathy causes and management

Answer 6

• Syndrome resulting from thiamine (vitamin B1) deficiency
  * Most cases result from alcohol abuse
  * If untreated (with IV thiamine replacement) may progress to irreversible Korsakoffs psychosis
  * Classical clinical triad

1. Acute confusional state
2. Ophthalmoplegia (especially upgaze)
3. Ataxia (and other cerebellar signs)

Question 7

Characteristics of Congenital nystagmus?

Answer 7

o Pendular nystagmus
o Can occur in any direction
o Most marked in neutral position

Question 8

Characteristics of peripheral cause of nystagmus

Answer 8

• Vestibular (apparatus, nerve or pathways - eg.
labyrinthitis, Meniere’s, syringobulbia, MS)
o Unidirectional jerk nystagmus
o Fast phases away from side of lesion
o Nystagmus increases when eyes look in the direction of the fast phase, away from side of lesion (Alexander’s law)

Question 9

Characteristic of a central cause of nystagmus

Answer 9

• Central (brainstem or cerebellar vermis)
o Bidirectional jerk nystagmus
o Direction of fast phase varies with direction of gaze

Question 10

Characteristic of a unilateral cerebellar hemisphere lesion.

Answer 10

• Unilateral cerebellar hemisphere lesion
o Nystagmus when looking in direction of lesion
o Fast phase towards lesion