Disorders of the Cerebellum (Week 3--Portera-Cailliau) Flashcards
Inputs to the cerebellum
Proprioceptive
Auditory
Visual
Somatosensory
Vestibular
Functions of the cerebellum
Postural control
Fine motor control
Balance
Eye movements
Symptoms of cerebellar dysfunction
Patient describes this
Nausea/vomiting
Dizziness
Room spinning (vertigo)
Hand shaking (tremor)
Loss of balance
Falls
Clumsiness
Slurred speech
Double vision
Difficulty concentrating
Signs of cerebellar dysfunction
Physical exam findings
Impaired extraocular movements
Hypometric saccades
Nystagmus
Dysarthria and scanning speech
Tremor
Dysmetria
Dysdiadochokinesia
Hypotonia
Romberg sign
Gait ataxia
Cerebellar disorders
Hereditary: Friedreich’s ataxia, ataxia-telangiectasia, spinocerebellar ataxias, olivopontocerebellar degeneration (also sporadic), episodic ataxias
Acquired: vascular (ischemic or hemorrhagic stroke), neoplastic and paraneoplastic, toxic and metabolic, infectious/inflammatory
Ataxia as a manifestation of other neurodegenerative disorders: multiple system atrophy
Midline lesions of the cerebellum
Off balance, walk with staggering gait, falls, slurred speech, walk/talk as if drunk
Lesion in one of cerebellar hemispheres
Clumsiness in one hand (or one leg), hands shake or flap around
Sudden (or episodic) nausea and vomiting if cerebellar lesion exerts pressure in brain
Romberg sign
Patient stand with eyes closed
Hereditary ataxias
Positive family hx, slowly/chronic progression of disease, widespread/pan-cerebellar symptoms, present in childhood or young adulthood
No specific treatment or cure other than supportive care and symptomatic treatment (adaptive devices, physical therapy, drugs for tremor or spasticity)
Spinocerebellar ataxias
Autosomal recessive, autosomal dominant or X-linked
A large group (29) of progressive, degenerative genetic diseases
Many are polyglutamine diseases (CAG triplet repeat expansion)
On MRI might see individual folia (shrunken cerebellum; can see this in other inherited ataxia too)
Friedreich’s ataxia
Autosomal recessive
Symptoms begin at age 5-15 (gait ataxia, falls) then develop club foot and hammer toes
Muscle weakness, areflexia, scoliosis (if scoliosis in boys, think Friederich’s ataxia!)
Cardiac abnormalities (cardiomyopathy, heart block)
10% get diabetes
Most live to young adulthood
Ataxia-telangiectasia
Autosomal recessive, rare
Presents in childhood (<10) with balance problems, dysarthria and motor delay
Affects cerebellum and immune system (agammaglobulinemia)
20% get cancer (leukemia, lymphoma)
Mild diabetes, frequent infections, premature graying of hair
Prominent blood vessels (telangiectasias) in sclera of eyes and in skin
Wheelchair by teenage years and die by early 20s due to recurrent infections
Olivopontocerebellar atrophy
Autosomal recessive, autosomal dominant (hereditary), or sporadic (multiple system atrophy, type C)
Progressive degeneration of cerebellum, pontine nuclei and inferior olive
Episodic ataxias
Autosomal dominant
Sporadic bouts of incoordination that are spontaneous or provoked by stress or intense emotion
Usually channelopathy
6 types but EA1 (mutation in gene for Kv1.1 K+ channel on Basket cells that inhibit Purkinje neurons) and EA2 (mutation in gene for Cav2.1 Ca2+ channel on Purkinje neurons) most common
Attacks last hours to days and some patients have progressive cerebellar atrophy
Ataxia with oculomotor apraxia
Rare disorder
Acquired ataxias
No family history of ataxia
Symptoms occur suddenly or evolve subacutely (weeks rather than months or years)
Focal signs of cerebellar dysfunction (unilateral)
May present in childhood or adulthood
Vascular (cerebellar stroke)
Ischemic or hemorrhagic stroke affecting cerebellum can result in acute onset ataxia
In many cases, and when only vermis affected, patients can have vomiting while exhibiting very mild truncal ataxia
Important to have the patient get up from gurney and try to walk because nausea might be the only symptom you notice if they stay laying down! If you have them walk in a straight line they won’t be able to! “Fatal gastroenteritis” isn’t gastroenteritis…it’s a cerebellar stroke that you’ve missed!
Also look for vascular risk factors, trauma, pt on warfarin/blood thinners
3 arteries that supply cerebellum
Superior cerebellar artery (SCA)
Anterior inferior cerebellar artery (AICA) off basilar artery
Posterior inferior cerebellar artery (PICA) off vertebral arteries
Neoplastic and paraneoplastic ataxias
Tumor in posterior fossa can cause ataxia
No family hx, slowly progressive or subacute, focal symptoms, known cancer
In children, medulloblastoma, which arises from 4th ventricle: presents with morning nausea/vomiting (projectile, in morning because of buildup of ICP) and headache and then child develops ataxia and diplopia, 6th nerve palsy, 80% 5 year survival
In adults, primary tumors in cerebellum or metastases: ataxia or signs of increased intracranial pressure (positional nausea/vomiting and headache)
Rarely, distant tumor elicits autoimmune reaction and causes paraneoplastic syndrome that affects cerebellum (neuroblastoma causing oposclonus-myoclonus in ~3% of affected children; gynecological neoplasms trigger cerebellar degeneration because of anti-Yo and anti-Ri antibodies that cross-react with antigens on Purkinje neurons)
Toxic-metabolic ataxia
Alcohol abuse: Vermian atrophy, Wernicke-Korsakoff syndrome from thiamine deficiency (ataxia, dementia, ophthalmoplegia = triad of symptoms)
Prescription drugs: anticonvulsants (Dilantin)
Inborn errors of metabolism occur in young children: mitochondrial disorders, Maple-syrup urine disease, Hartnup disease, Refsum syndrome
Vitamin E deficiency causes spinocerebellar ataxia (because of Crohn’s disease, pancreatic insufficiency, rare disorders of fat metabolism)
Wernicke-Korsakoff syndrome
Thiamine (B1) deficiency can lead to this; alcoholics
Ataxia, dementia, ophthalmoplegia = triad of symptoms
Initially presents as Wernicke encephalopathy: ophthalmoplegia (often with nystagmus), confusion and ataxia; if untreated can progress to coma and death; treat with IV thiamine with glucose (“banana bag”)
In chronic thiamine deficiency, patients develop Korsakoff psychosis: global amnesia, confabulation and hallucinations; degeneration or necrosis of mammillary bodies (Papez memory circuit) sometimes seen on autopsy
Inflammatory/infectious
No family hx, acute presentation, focal symptoms, remote history of other focal neurologic deficits (plaque in one part of brain but not others)
Neurocysticerosis, immune-compromised patients with opportunistic infections that involve cerebellum
Demyelinating plaques in patients with MS in white matter of brainstem or cerebellum: appendicular or midline ataxia; had previous bouts of focal and transient neurologic symptoms
Viral infections can cause cerebellitis in children or adults
