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

Block 5: Neuroscience > Disorders of the Cerebellum (Week 3--Portera-Cailliau) > Flashcards

Flashcards in Disorders of the Cerebellum (Week 3--Portera-Cailliau) Deck (22):
1


Inputs to the cerebellum


Proprioceptive

Auditory

Visual

Somatosensory

Vestibular

2


Functions of the cerebellum


Postural control

Fine motor control

Balance

Eye movements

3


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

4


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

5


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

6


Midline lesions of the cerebellum


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

7


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

8


Romberg sign


Patient stand with eyes closed

9


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)

10


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)

11


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

12


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

13


Olivopontocerebellar atrophy


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

Progressive degeneration of cerebellum, pontine nuclei and inferior olive

14


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

15


Ataxia with oculomotor apraxia


Rare disorder

16


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

17


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

18


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

19


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)

20


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)

21


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

22


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

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