Cerebellar disease

Question 1

Anatomy of cerebellum

Answer 1

Recieves direct input from vestibular sensory apparatus, and plays an inhibitory role in the modulation of the brainstem vestibular neuclei

Question 2

Function of cerebellum

Answer 2

Major coordination centre of the brain

Coordinates muscle activity and movements induced by the upper motor neurons

Maintenance of equilibrium and regulation of muscle tone

No role in gait but important in coordination of movement

Proprioceptive role at subconcious level

Coordiniating role in menace response

Question 3

Clinical signs of dysfunction of the cerebellum

Answer 3

Cerebellar ataxia
- head: intention tremor
- body: truncal ataxia
- limbs: broad-based stance, dysmetria, hypermetria

Ipsilateral menace deficit (normal vision and facial motor function

Question 4

Pardoxical vestibular syndrome

Answer 4

Vestibular signs can be seen with cerebellar lesions that involve the flocullonodular lobe or the
caudal cerebellar peduncle.

Vestibular signs occur contralateral to the side of the actual lesion.

These lesions also often affect the
proprioceptive and motor pathways in the region, resulting in postural reaction deficits ipsilateral to
the lesion, but contralateral to the head tilt.

The vestibular signs are contralateral due to loss of
inhibition to vestibular nuclei on the affected (ipsilateral) side

Question 5

Vascular causes of cerebellar disease

Answer 5

Infarction, CVA

Question 6

Infectious/inflammatory causes of cerebellar disease

Answer 6

Meningoencephalitis

Neospora caninum

Question 7

Idiopathic causes of cerebellar disease

Answer 7

Generalised tremor syndrome ‘white shakers’

Steroid responsive tremor syndrome

Question 8

Traumatic causes of cerebellar disease

Answer 8

Brain trauma

Question 9

Toxic causes of cerebellar disease

Answer 9

Metronidazole

Question 10

Anomalous causes of cerebellar disease

Answer 10

Feline cerebellae hypoplasia

Aplasia

Cysts

Question 11

Neoplastic causes of cerebellar disease

Answer 11

Brain tumour

Question 12

Nutritional causes of cerebellar disease

Answer 12

Thiamine deficiency

Question 13

Degenerative causes of cerebellar disease

Answer 13

Cerebellar cortical degeneration/abiotrophy

Lysosomal storage diseases

Neurodegenerative diseases

Question 14

Pathogenesis of feline cerebellar hypoplasia

Answer 14

Results from an in-utero infection with panleukopaenia virus (parvovirus)

Affects the germinal layer of the cerebellum and prevents further cerebellar development

Question 15

Clinical signs of feline cerebellar hypoplasia

Answer 15

Cerebellar signs like ataxia and intention tremor

Question 16

Diagnosis of feline cerebellar hypoplasia

Answer 16

Antemortem testing often results in negative/normal findings

MRI of brain can confirm small size of cerebellum - not specific

Question 17

Treatment of feline cerebellar hypoplasia

Answer 17

no treatment

Question 18

Prognosis of feline cerebellar hypoplasia

Answer 18

Fair, if animal only mildly affected

Signs remain static or often improve as cat compensates

Question 19

Pathogenesis of neospora caninum infection

Answer 19

Protozoal parasite

Predilection for cerebellum in adult dogs

Infection may occur by ingestion of cysts in infected meat products or faeces

Question 20

Clinical signs of neospora caninum infection

Answer 20

Chronic, progressive cerebellar syndrome

Question 21

Diagnosis of neospora caninum infection

Answer 21

Serology to demonstrate active infection

Brain mRI may confirm characteristic cerebellar lesion

CSF for PCR confirmation

Question 22

Treatment of neospora caninum infection

Answer 22

Clindamycin at prolonged high doses of 15-20mg/kg bid for several months

Question 23

Prognosis of neospora caninum infection

Answer 23

Many animals will recover with treatment

Question 24

Cerebellar abiotrophy

Answer 24

Degenerative condition affecting cerebellum in young dogs

Often starts in young adult, may be progressive up to 1-2 years of age then stabilise

Diagnosis difficult, but prognosis is fair

Question 25

Tremor syndromes

Answer 25

Involuntary and uncontrollable rhythmic movement of all or part of the body

Cerebellar disease is commonest cause of head tremor

Question 26

Types of tremor

Answer 26

Whole body tremor

Head tremor

Orthostatic tremor

Poorly understood tremors of one or more limbs

Question 27

Two causes of whole body tremor

Answer 27

‘Little white shaker’ syndrome

Idiopathic tremor

Plus certain toxin ingestions e.g. mycotoxins

Question 28

Two main types of head tremor

Answer 28

Cerebellar disease, intention tremor

Idiopathic head bobbing

Question 29

Orthostatic tremor

Answer 29

Usually pelvic limbs, but sometimes thoracic in large or giant breeds

Associated with weight bearing

Benign and apparently no consequence

Question 30

Little white shaker syndrome

Answer 30

An acute inflammatory (probably autoimmune) cerebellitis, seen mainly in smaller and toy breeds,
especially (but not only) white dogs such as Maltese.

It may however also be seen in larger and non- white breeds!

Affected dogs present with an insidious onset of whole body tremor which may wax
and wane, and worsen with excitement.

When at rest the tremor will largely disappear.

If excited or stimulated, affected animals may be variably ataxic.

Diagnosis requires identification of lymphocytic pleocytosis in CSF alongside characteristic signs and
elimination of toxicity as a differential from careful history taking.

Treatment requires anti-inflammatory doses of prednisolone (0.5 mg/kg bid) usually for a few weeks, although most dogs respond rapidly and prognosis is good.