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