Cerebellar Disorders/ Diseases Flashcards
Features of the cerebellum
- largest part of the hindbrain, located in posterior cranial fossa
- comprises of two hemispheres joined by the vermis
sub-divided into three lobes – anterior, posterior, and flocculonodular,
separated by two transverse fissures - forms 10% brain volume, but is neuron rich
- contains 80% of brain neurons organised in a dense cellular layer
What is the most important cell layer in the cerebellum?
Purkinje cell layer:
Most important layer -Only output of the
cerebellar cortex
Cerebellar degeneration > Purkinje cell loss > ataxia
Where are Purki cells found?
Between the molecular and granular layer
What is the role of the cerebellum?
- accuracy and coordination
- motor control and learning
- contributes to timing and sensory acquisition
- involved in the prediction of the sensory consequences of action
- eye movements, speech, limb movements, fine motor skills, gait, posture,
balance, cognition
What is ataxia?
- ‘lack of order’
- term used to describe problems with
balance and co-ordination - heterogeneous group of disorders
- many different causes
- majority permanent and progressive
Epidemiology of ataxia
rare condition
10, 000 adults and 500 children
Inherited types of ataxia
- autosomal dominant
- autosomal recessive
- X-linked
- mitochondrial
- metabolic*
Types of acquired ataxia
- toxic / metabolic*
- immune mediated
- infective
- degenerative
- structural (trauma, neoplastic)
Types of autosomal dominant ataxia
Several types of
spinocerebellar ataxias
SCA 6
* episodic ataxias
EA 2
Autosomal recessive ataxia
- Friedreich’s ataxia
(FA) - SPG7
- ataxia oculomotor
apraxia type 1 and
type 2 (AOA1, AOA2) - ataxia telangiectasia
- ARSACS
X linked ataxia
Fragile X Tremor
Ataxia Syndrome
(FXTAS)
Mitochondrial ataxia
- mtDNA
- nuclear DNA
Metabolic ataxia
- Niemann-Pick Type C
- Tay-Sach’s disease
Toxic/ metabolic ataxia
- alcohol
- vitamin deficiencies
- drug
Immune mediated ataxia
- paraneoplastic cerebellar degeneration
- gluten related
- Primary Autoimmune Cerebellar Ataxia
(PACA)
anti-GAD related
Infective causes of ataxia
multi-system
atrophy
cerebellar variant
(MSA-C)
* progressive
supranuclear
palsy (PSP)
Structural causes of ataxia
superficial
siderosis
* primary tumour
medulloblastoma
* vascular
History for cerebellar dysfunction
- age of onset
- course / rate of progression
- additional symptoms
- pattern of involvement
- family history
- drug / alcohol hx
- social history
Symptoms of cerebellar dysfunction
- dizzy – unsteady / wobbly / clumsy
- falls, stumbles
- difficulty focusing / double vision / ‘oscillopsia’
- slurred speech
- problems with swallowing
- tremor
- problems with dexterity / fine motor skills
Clinical signs of cerebellar dysfunction
- nystagmus / jerky (saccadic) pursuit / hypo or hypermetropic saccades / optic atrophy / ptosis
- dysarthria
- intention tremor / myoclonus
- dysmetria / past pointing / dysdiadochokinaesia
- heel - shin ataxia
- gait / limb / truncal ataxia
- tone / reflexes
SARA - (Scale for the Assessment and Rating of Ataxia)
- mild mobilising independently or
with one walking aid
moderate mobilising with 2 walking aids
or walking frame
severe predominantly wheelchair
dependent
Diagnostic tests for cerebellar dysfunction
Blood tests in primary care:
FBC, U&E, extended LFT’s
* HbA1c, B12, folate, TSH
* ESR, CRP
* gluten related serology*
Investigations in secondary care (depending on clinical presentation)
MRI Brain:
* essential in all patients with ataxia
* excludes structural causes
* demonstrates cerebellar atrophy*
* MR Spectroscopy Cerebellum – unique to Sheffield
sensitive in detecting cerebellar dysfunction
* CT brain, if MRI contraindicated
* MRI brain demonstrates cerebellar atrophy and / or dysfunction
What will imaging with MRI exclude?
cerebrovascular damage (posterior circulation stroke affecting the cerebellum or its connections)
primary tumours (haemangioblastoma, acoustic neuroma, medulloblastoma)
secondary tumours
hydrocephalus, Chiari malformations
demyelinating disorders / multiple sclerosis
white matter disease in leukodystrophy
cerebellar dysgenesis/malformations
