Ataxias
spinocerebellar ataxias basics
- autosomal dominant - many types w/ overlapping clinical features - some are CAG triplet repeat disorders - usually 3rd-5th decade but variable onset - dx: genetic testing
other common characteristics of Friedreich Ataxia
- foot deformity - DM - cardiac hypertrophy
differential for pediatric cerebellar ataxia
- neoplasm: MEDULLOBLASTOMA - drug intox - infeciton/ inflammation - trauma - inborn error of metabolism
3 types of ataxias
1. cerebellar 2. sensory 3. misc- vestibular, thalamic, frontal
non progressive cerebellar ataxia- Dandy Walker Malformation: triad
1. complete or partial a genesis of vermis 2. cystic dilation of the 4th ventricle 3. enlarged posterior fossa w/ upward displacement of lateral sinuses, tentorium and torcular herophili
progression of Dandy Walker malformation
1. early infancy- slow motor dvlpt and progressive enlargement of skull 2. older children- raised ICP/ cerebellar dysfxn: VP SHUNT FOR HYDROCEPHALUS - other features: corpus callosum dysgensis, holoprosencephaly malformations of the heart, face, limbs, digits
chronic- m's to years symmetrical ataxia causes
1. inherited ataxia 2. MSA- cerebelar 3. paraneoplastic 4. autoimmune 5. hypothyroidism
mean age death for Friedreich ataxia
4th decade due to cardiac/ respiratory collapse
thalamic infarct ataxia
CL ataxia w/ sensory loss
lab for Friedreich Ataxia
DNA mutation analysis
autosomal recessive ataxia- Friedreich Ataxia
GAA triplet repeat expansion, reduced Frataxin protein - progressive limb and gait ataxia develops before 30 yo age - ambulation los by 9-15 years after onset - eventual areflexia, distal deep sensory loss, motor weakness of lower extremities, dyarthria, extensor plantar responses
lateral cerebellar lesions-->
IL limb ataxia
subacute- days to weeks- symmetrical ataxia due to?
alcoholic nutritional- vit b1/ B12 deficiency
vestibulocerbellum lesion
ataxic gait, truncal ataxia, vertigo, nausea, other eye mvmt
SCA 6
benign, late onset
dysdiadochokinesia w/ cerebellar ataxia
breakup and irregularity when limb attempts to carry out rapid, alternating mvmt
MRI for Friedreich ataxia
cerebellar atrophy and thin spinal cord
chronic focal ataxia etiology
congenital lesion- Chiari or Dandy-Walker malformation
sensory ataxia
failure of relay of proprioceptive info to the CNS - dorsal column or large fiber sensory neuropathy (joint position/ vibration) - marked worsening of the coordination when the EYES ARE CLOSED - no asst features of cerebellar ataxia - Pseudo athetosis and ROMBERG sign
spinocerebellum lesion
gait ataxia or truncal ataxia
reflexes/ tone w/ cerebellar ataxia
hypotonia and slow deep tendon reflexes
cerbellar ataxia pathophysio
intact sensory receptors and afferent pathways integration of proprioception is faulty
tremor w/ cerebellar ataxia
intention tremor
alcoholic pt acute ataxic gait
intoxication thiamine deficiency (wernicke encephalopathy) start thiamine IV
acute symmetrical ataxia due to?
intoxication- EtOH, lithium acute viral cerebellitis post infectious syndrome
definition of ataxia
lack of coordination resulting in breakdown of normal execution of a voluntary movements
neocerebellum lesion
lateral hemispheres IL dysdiadochokinesia, dysmetria, intention tremor
chronic ataxic gait w/ alcoholic pt
midline cerebellar atrophy, neuropathy in feet, dorsal column damage from B12 deficiency
dysmetria w/ cerebellar ataxia
misjudging of distance, overshooting (hypermetria) and undershooting, hypometria of target
Spinocerebellar ataxia 3- Machado Joseph Disease
most common SCA CAG repeat- Ataxin 3 protein ataxia w/ opthalmoplegia, spasticity, parkinsonism, facial myokymia, neuropathy, cognitive decline death in 15-20 yrs due to aspiration pneumonia
subacute focal ataxia etiology
neoplastic- cerebellar glioma demyelinating- MS
geriatric ataxia
normal, age related change- decrease in gait speed, stride length, posterior shift in center of gravity - multifactorial gait disorder -tx: physical therapy: gait retraining, reassess medication list
eye movements w/ cerebellar attaxia
nystagmus, dysmetric saccades
scanning dysarthria w/ cerebellar ataxia
spoken words broken into separate syllables, separated by noticeable pause, spoken w/ varying force
midline cerebellar lesions-->
truncal ataxia
ataxia of gait w/ cerebellar ataxia
unsteadiness w/ wide base, body sawing, inability to walk heel to toe
acute vascular cerebellar result
usually asymmetric cerebellar ataxia associated motor/ sensory loss, CN palsy may be asst w/ impaired consciousness due to compression or increased ICP get CT scan
acute focal ataxia etiology
vascular- cerebellar infarction, hemorrhage
SCA 7 sx
vision loss