Ataxia Flashcards
Definition of ataxia
incoordination of movement and balance due to dysfunction
- cerebellar
- sensory or motor pathways (connecting to CB)
Aetiology of congenital cerebellar ataxia - congenital CNS anomalies
dandy-walker syndrome, chiari malformation, encephalocele, agenesis of CB vermis
Aetiology of congenital cerebellar ataxia - spinocerebellar degenerative
AT, Friedrich ataxia, olivopontocerebellar atrophy, abetalipoproteinemia (metabolic)
Aetiology of congenital cerebellar ataxia - other degenerative
GM2 gangliosidosis, neuronal ceroid lipofuscinosis, pelizaeus-merbacher disease
Aetiology of congenital cerebellar ataxia - metabolic
arginosuccuric aciduria, maple syrup disease, pyruvate decarboxylase deficiency, hartnup disease, vitamin e deficiency
Aetiology of acquired infectious cerebellar ataxia
acute cerebellar ataxia (post-viral e.g. varicella, coxsackie, echovirus), cerebellar abscess
Miller Fischer variant of GBS (ataxia, ophthalmoplegia, areflexia)
Aetiology of acquired toxin causes of cerebellar ataxia
ETOH, ethylene glycol, sedatives, hypnotics, thallium (used occasionally as pesticides), lead, mercury, hydrocarbon fumes
Anticonvulsants (CBZ and especially phenytoin, when serum level >30mcg/mL - 120umol/L)
Aetiology of acquired tumour causes of cerebellar ataxia
- Cerebellar tumours
- Posterior fossa tumours: medulloblastoma, astrocytoma
- Frontal lobs tumours: ataxia by destruction of fibres connecting frontal lobe with CB
- Neuroblastoma: encephalopathy characterised by progressive ataxia, myoclonic jerks, opsoclonus (non-rhythmic horizontal and vertical oscillation of the eyes)
Other than trauma, what are other aetiologies of cerebellar ataxia
Vascular events, migraine, seizures
What vestibular disease is an aetiology for cerebellar ataxia?
acute laryinthitis - middle ear infection, intense vertigo, vomiting and abnormal labyrinthine function (esp ice water caloric testing)
What posterior column aetiology for cerebellar ataxia?
- subacute combined degeneration of the cord: B12 def (symptoms similar to friedrich’s ataxia) - UMNL of LL with absent ankle reflexes, dorsal column loss, peripheral sensory neuropathy, also optic atrophy and dementia
- AT
- tabes dorsalis
- diabetes
- hypothyroidism
Causes of peripheral neuropathy?
D = drugs (isoniazid, vincristine, phenytoin, nitrofurantoin, cisplatin, heavy metals, amiodarone) A = Alcohol M = metabolic - diabetes, CRF, neurodegenerative I = infective - GBS but usually predominantly motor T = tumour (leukaemia, lymphoma) B = B12 deficiency I = Idiopathic C = Connective tissue disease (SLE, PAN) H = Hereditary - HSMN
Causes of acute onset ataxia
- infectious - acute post infectious, labrynthitis, miller fischer variant GBS)
- drug ingestion
- seizure, head injury, vascular event (stroke), brain tumour, hydrocephalus
Causes of developing chronic ataxia on history
- tumour
- neurodegenerative
What are some underlying causes of ataxia on history
o CNS abnormality/degenerative – associated congenital anomalies, FHx
o Metabolic – FHx
o Infectious – features of acute infectious, labyrinthitis
o Tumour – Sx of ICP
o Exposure to drugs and toxins
o Recurrent respiratory and sinus infections (ataxia telangiectasia)
What are developmental features on history that you want to discern ataxia
Determine if clumsy or true ataxia
Eye signs of cerebellar dysfunction?
nystagmus (lateral gaze)
Speech signs of cerebellar dysfunction?
Scanning dysarthria, explosive speech ‘sizzling sausages’
Truncal signs of cerebellar dysfunction?
truncal ataxia, head titubation
Limb signs of cerebellar dysfunction?
Dysmetria (finger-nose or heel-shin)
Dyssynergia (hand movements clumsy and jerky)
Dysdiadokokinesia (at back hand with the other)
Romberg +ve
+/- hypotonia, +/- reduced tendon reflexes
Gait signs of cerebellar dysfunction?
broad based and veer toward side of abnormality
What might reduced growth point towards in an ataxia case?
Ataxis Telangiectasia, metabolic disorder, abetalipoproteinaemia
What might high blood pressure suggest in an ataxia case?
ICP, neuroblastoma
What might fever suggest in a ataxia case?
CB abscess, meningitis, encephalitis
Upper limb signs in an ataxia case?
Clubbing (repeated infection in ataxia telangiectasia) CLD signs (Wilson's Dx)
Head and neck signs in an ataxia case?
Scalp - any scars from surgery Bruits @ head - AVM CB malformation Eyes o Cataracts (abetalipoproteinaemia) o KF rings (Wilson’s) o Fundoscopy (Lawrence, metabolic) ENT exam o Hypertrophied gums (phenytoin) o Recurrent nasal, middle ear and lung infections (AT) o Hypoplastic tonsils (AT) o SNL hearing loss (FA) Axillary and cervical nodes - lymphoma (AT)
Chest signs in an ataxia case?
Bone pain (AT --> increased risk of leukemia) CVS exam (HOCM --> FA)
Abdomen signs in an ataxia case?
Gonadal atrophy (AT)
Neuroblastoma mass
HSM (AT –> increased risk of leukemia, metabolic disorders)
MSK signs in an ataxia case?
In Fredriech ataxia:
- pes cavus (typical)
- hammer toes
- kyphoscoliosis
What might you look for in a formal CNS exam in an ataxia case?
- Developmental delay (AT, metabolic disorders)
- LMN: abetalipoproteinaemia, FA, AT
- Sensory disturbance: abetalipoproteinaemia, FA
- Gait: veers toward involved side (if cerebellar)
What investigations might you want in an ataxia case?
Bloods:
- FBC, UEC, +/- toxicology screen blood (and urine) +/- metabolic screen (amino acids, lactate, pyruvate, ammonia, pH, ketones)
What imaging might you want in an ataxia case?
CT/MRI needed: nil nil lesion –> detailed metabolic and genetic evaluation
What special investigation might you want in an ataxia case?
+/- LP (post imaging)
VMA/HVA urine if think neuroblastoma (need image of chest and abdomen as well)
