Cerebellar disease Flashcards
Anatomy of cerebellum
Recieves direct input from vestibular sensory apparatus, and plays an inhibitory role in the modulation of the brainstem vestibular neuclei
Function of cerebellum
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
Clinical signs of dysfunction of the cerebellum
Cerebellar ataxia
- head: intention tremor
- body: truncal ataxia
- limbs: broad-based stance, dysmetria, hypermetria
Ipsilateral menace deficit (normal vision and facial motor function
Pardoxical vestibular syndrome
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
Vascular causes of cerebellar disease
Infarction, CVA
Infectious/inflammatory causes of cerebellar disease
Meningoencephalitis
Neospora caninum
Idiopathic causes of cerebellar disease
Generalised tremor syndrome ‘white shakers’
Steroid responsive tremor syndrome
Traumatic causes of cerebellar disease
Brain trauma
Toxic causes of cerebellar disease
Metronidazole
Anomalous causes of cerebellar disease
Feline cerebellae hypoplasia
Aplasia
Cysts
Neoplastic causes of cerebellar disease
Brain tumour
Nutritional causes of cerebellar disease
Thiamine deficiency
Degenerative causes of cerebellar disease
Cerebellar cortical degeneration/abiotrophy
Lysosomal storage diseases
Neurodegenerative diseases
Pathogenesis of feline cerebellar hypoplasia
Results from an in-utero infection with panleukopaenia virus (parvovirus)
Affects the germinal layer of the cerebellum and prevents further cerebellar development
Clinical signs of feline cerebellar hypoplasia
Cerebellar signs like ataxia and intention tremor
Diagnosis of feline cerebellar hypoplasia
Antemortem testing often results in negative/normal findings
MRI of brain can confirm small size of cerebellum - not specific
Treatment of feline cerebellar hypoplasia
no treatment
Prognosis of feline cerebellar hypoplasia
Fair, if animal only mildly affected
Signs remain static or often improve as cat compensates
Pathogenesis of neospora caninum infection
Protozoal parasite
Predilection for cerebellum in adult dogs
Infection may occur by ingestion of cysts in infected meat products or faeces
Clinical signs of neospora caninum infection
Chronic, progressive cerebellar syndrome
Diagnosis of neospora caninum infection
Serology to demonstrate active infection
Brain mRI may confirm characteristic cerebellar lesion
CSF for PCR confirmation
Treatment of neospora caninum infection
Clindamycin at prolonged high doses of 15-20mg/kg bid for several months
Prognosis of neospora caninum infection
Many animals will recover with treatment
Cerebellar abiotrophy
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
Tremor syndromes
Involuntary and uncontrollable rhythmic movement of all or part of the body
Cerebellar disease is commonest cause of head tremor
Types of tremor
Whole body tremor
Head tremor
Orthostatic tremor
Poorly understood tremors of one or more limbs
Two causes of whole body tremor
‘Little white shaker’ syndrome
Idiopathic tremor
Plus certain toxin ingestions e.g. mycotoxins
Two main types of head tremor
Cerebellar disease, intention tremor
Idiopathic head bobbing
Orthostatic tremor
Usually pelvic limbs, but sometimes thoracic in large or giant breeds
Associated with weight bearing
Benign and apparently no consequence
Little white shaker syndrome
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.
