Disorders of the Cerebellum (Week 3--Portera-Cailliau)

Question 1

Inputs to the cerebellum

Answer 1

Proprioceptive

Auditory

Visual

Somatosensory

Vestibular

Question 2

Functions of the cerebellum

Answer 2

Postural control

Fine motor control

Balance

Eye movements

Question 3

Symptoms of cerebellar dysfunction

Answer 3

Patient describes this

Nausea/vomiting

Dizziness

Room spinning (vertigo)

Hand shaking (tremor)

Loss of balance

Falls

Clumsiness

Slurred speech

Double vision

Difficulty concentrating

Question 4

Signs of cerebellar dysfunction

Answer 4

Physical exam findings

Impaired extraocular movements

Hypometric saccades

Nystagmus

Dysarthria and scanning speech

Tremor

Dysmetria

Dysdiadochokinesia

Hypotonia

Romberg sign

Gait ataxia

Question 5

Cerebellar disorders

Answer 5

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

Question 6

Midline lesions of the cerebellum

Answer 6

Off balance, walk with staggering gait, falls, slurred speech, walk/talk as if drunk

Question 7

Lesion in one of cerebellar hemispheres

Answer 7

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

Question 8

Romberg sign

Answer 8

Patient stand with eyes closed

Question 9

Hereditary ataxias

Answer 9

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)

Question 10

Spinocerebellar ataxias

Answer 10

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)

Question 11

Friedreich’s ataxia

Answer 11

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

Question 12

Ataxia-telangiectasia

Answer 12

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

Question 13

Olivopontocerebellar atrophy

Answer 13

Autosomal recessive, autosomal dominant (hereditary), or sporadic (multiple system atrophy, type C)

Progressive degeneration of cerebellum, pontine nuclei and inferior olive

Question 14

Episodic ataxias

Answer 14

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

Question 15

Ataxia with oculomotor apraxia

Answer 15

Rare disorder

Question 16

Acquired ataxias

Answer 16

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

Question 17

Vascular (cerebellar stroke)

Answer 17

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

Question 18

3 arteries that supply cerebellum

Answer 18

Superior cerebellar artery (SCA)

Anterior inferior cerebellar artery (AICA) off basilar artery

Posterior inferior cerebellar artery (PICA) off vertebral arteries

Question 19

Neoplastic and paraneoplastic ataxias

Answer 19

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)

Question 20

Toxic-metabolic ataxia

Answer 20

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)

Question 21

Wernicke-Korsakoff syndrome

Answer 21

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

Question 22

Inflammatory/infectious

Answer 22

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