Ataxia
When does SCA usually onset?
3rd-5th decade but variable
What is the mean age at death for FA pts?
4th decade due to cardiac/respiratory effects
Classic presentation of sensory ataxia?
B12 deficiency, copper deficiency
What is affected in a sensory ataxia?
Dorsal column or large fiber sensory neuropathy (joint position/vibration)
Features of cerebellar ataxia
- ataxia of gait - dysdiadochokinesia - dysmetria - loss of rebound - intention tremor - eye mvmts - scanning dysarthria - hypotonia
what are the three types of ataxia?
- cerebellar - sensory - misc: vestibular, thalamic, frontal dysequilibrium ataxia
T/F: there is no assoc features of cerebellar ataxia
True
T/F: there is no effective treatment for friedreichs ataxia?
True
Symmetrical ataxia
acute (hrs-days), subacute (days-wks), chronic (mo-yrs)
Describe the alcoholic pt
acute ataxic gait - thiamine def (wernicke encephalopathy - confusion, eye movements) chronic ataxic gait - midline cerebellar atrophy, neuropathy in ft, dorsal column damage from B12 deficiency
Swelling can cause what other signs in the brain?
assoc w/motor/sensory loss, cranial nerve palsies from brainstem involvement
Spinocerebellar Ataxias (SCA)
autosomal dominant ataxia types 1-29, usually GRADUAL onset of cerebellar ataxia w/ features involving other systems CAG triplet repeats
Friedreich Ataxia
autosomal recessive ataxia presents younger age GAA triplet repeat... reduced Frataxin protein
SCA 6
benign, late onset
Symmetrical ataxia distribution
both side
Dysdiadochokinesia
breakup and irregularity that occur when limb is attempting to carry out rapid alternating movements (like flipping hand in palm)
other features of dandy walker?
corpus callosum dysgenesis, holoprosencephaly, malformation of heart, face, limbs, digits
subacute symmetrical ataxia
days-weeks intoxication (Hg, solvents, gas, glue), cytotoxic chemo drugs - cytarabine, alcoholic nutritional deficiences (B1 and B12 deficiency), EBV, CMV, Creutzfeldt jakobs disease
Focal subacute ataxia
days-wks Neoplastic: cerebellar glioma or met tumor (+on MR/CT) Demyelinating: MS, AIDS
Sensory ataxia
failure of relay or proprioceptive info to CNS
vestibulocerebellum
flocculonodular lobe & tiny part of vermis ataxic gait, truncal ataxia, vertigo, nausea, nystagmus & other eye mvmt abnormalities
What are other common characteristics of Friedreich Ataxia?
foot deformity, scoliosis, DM and cardiac hypertrophy MR results: cerebellar atrophy and thin spinal cord abnormal NCV/EMG
Acute symmetrical ataxia
hours-days intoxication (OH, Li, barbs), acute viral cerebellitis, post infective syndrome - usually viral
Focal acute ataxia
hr-days Vascular: cerebellar infarc, hemorrhage Infectious: cerebellar abcess (+mass on MR/CT)
Cerebellar Ataxia
intact sensory receptors & afferent pathways, just the integration of proprioception is faulty
What do lateral cerebellar lesions cause?
ipsilateral limb ataxia
What is ataxia?
lack of coordination resulting in breakdown of normal execution of voluntary movement
Neocerebellum (pontocerebellum)
lateral hemispheres ipsilateral dydiodochokinesia, dysmetria, intention tremor
Pediatric presentation of ataxia
may appear well, but wobbly when sitting. Typically a viral infection precedes these episodes commonly intoxication
Dysmetria
misjudging of distance, overshooting (hypermetria) and undershooting (hypometria) of target
What symptoms appear if you damage cerebellar inflow and outflow tracts?
mixture of features.... including rubral tremor, thalamic ataxia, frontal gait ataxia
Chronic symmetrical ataxia
mo-yrs Inherited ataxia, paraneoplastic, autoimmune, hypothyroidism, tabes dorsalis,
Focal chronic ataxia
mo-yrs stable gliosis 2nd to vascular lesion or demyelinating plaque Congenital lesion: chiari or dandy-walker malformation
Machado Joseph Disease (SCA-3)
most common SCA CAG repeat, ATXN3 gene... Ataxin 3 protein presenting sxs: opthalmoplegia, spasticity, parkinsonism, facial myokymia, neuropathy, cognitive decline
Dandy Walker malformation
non progressive cerebellar ataxia triad: - a-genesis of vermis - dilatation of 4th vent - enlarged post. fossa
Geriatric presentation of ataxia
normally tend to be age related (>65) if it occurs acutely, get a CT of head
What develops before the age of 30?
progressive limb and gait ataxia ambulation lost by 9-15 yrs after onset
How does dandy walker present in older children?
raised ICP and signs of cerebellar dysfunction - VP shunt for hydrocephalus
How does Dandy walker present in early infancy?
slower motor development and progressive enlargement of skull
Scanning Dysarthria
spoken words are broken up into separate syllables, often separated by a noticeable pause, and spoken w/varying voice
What might cause contralateral ataxia w/sensory loss?
thalamic infarcts
Vascular incidents
think acute, usually asymmetric, ischemia or hemorrhage in cerebellum or brainstem cerebellar pathways
Intention (terminal) tremor
tremor that presents when they reach out for an object and begin to tremor once extended
What do Midline cerebellar lesions cause?
truncal ataxia
Ataxia of gait
unsteadiness w/wide base, body swaying, and inability to walk on tandem (heel-to-toe)
Spinocerebellum
vermis and paravermian region gait ataxia or truncal ataxia
What makes the sensory ataxia worse?
worsening of coordination occurs when the eyes are closed.
focal ataxia distribution
just one side
Eye movements
nystagmus, dysmetric saccades
SCA 7
vision loss