Ataxia Flashcards
Ataxia definition:
• An inability to generate a normal or expected voluntary movement trajectory that cannot be attributed to weakness or involuntary muscle activity (chorea, dystonia, myoclonus, tremor) about the affected joints. In simple terms, ataxia is the inability to make smooth, accurate and coordinated movements, not due to weakness or movement disorders.
Ataxia results from:
impairment of spatial pattern of muscle activity or from impairment of the timing of that activity, or both.
Ataxia affects:
motor control of eyes, speech, trunk and limbs.
Nystagmus =
oscillatory rhythmic eye movements
Saccadic intrusions =
involuntary conjugate fast eye movements that interrupt fixation
Undershooting of saccades =
Overshooting of saccades=
hypometria.
hypermetria.
Imprecise production of sounds
Dysarthria
Poor regulation of prosody
Scanning speech = explosive speech.
Bobbing of the head and trunk
Titubation
Imprecise targeting of distal limb movements
Dysmetria
Errors in relative timing of components of complex movements resulting in uncoordinated, abrupt movement. May split up a complex movement into smaller movements.
Dyssynergia
Dysdiadochokinesia
Errors in rate and regularity of rapid alternating movements. Impaired ability to perform rapid, alternating movements
Intention tremor
Tremor at the end of movement, seen on finger-to-nose, heel-to-shin testing
Another name for the Flocculonodular lobe ___.
Lesion of this part of the cerebellum causes ___.
Vestibulocerebellum.
Causes:
1. Nystagmus and other eye movement abnormalities.
2. Balance problems (sitting/standing, gait) due to equilibrium dysfunction - cant tell body position.
Which part of the body does the vermis of the cerebellum control__. Lesions of the vermis cause__.
Midline, axial trunk, proximal muscles.
Lesions cause:
1. Trunk movements: unsteadiness while standing or sitting. Titubations.
2. Gait ataxia.
Which part of the body do the hemispheres of the cerebellum control __. Lesions of the cerebellar hemispheres cause__.
Lateral, distal limb muscles. Lesions cause: 1. Limb ataxia: Dysmetria, Dysdiadochokinesis, Intention tremor. 2. Dysarthria 3. Hypotonia.
Problems with the vestibular system cause__.
Vertigo, nausea, nystagmus, abnormal vestibulo ocular reflex.
A positive Romberg sign is __ and it indicates an impairment in ___.
Loss of proprioception input leads to reliance on visual input to maintain posture. (Fall over when close eyes).
Impairment in Posterior columns in spinal cord. Causes Sensory Ataxia.
Damage of peripheral nerves of the sensory pathway can result in ___.
- Impairment of proprioception and vibration.
- Pain, temperature symptoms.
- Decreased or absent deep tendon reflex.
Acute ataxia could be from:
1. Intoxication Examples: alcohol, antiepileptic drugs, antihistamines, lots of other drugs. 2. Post infectious. 3. Demyelinating: • Acute disseminated encephalomyelitis (ADEM) • Multiple sclerosis (MS) 4. Migraine: Basilar migraine, or BPV 5. Vascular: infract, hemmorhage.
Chronic ataxia
- Tumors
2. Hereditary - there are a lot.
1/3 of all acute ataxia in kids: ___
Drug ingestion - 1/3 of all acute ataxia in kids. (young - accident; adolescent - substance abuse). EtOH, antiepileptics, benzos, antihistamines. Often accompanied by confusion, dysarthria. Urine tox screen in ER.
Most common cause of childhood ataxia ___.
Acute (Postinfectious) Cerebellar Ataxia (APCA). An autoimmune phenomenon incited by infection (cross reaction of antibodies against cerebellar epitopes). • Often has antecedent viral febrile illness (varicella, mumps, EBV, etc). Mostly affects preschool-age children (2 ~ 4yo).
NO extracerebellar neurologic signs (mental status changes, seizure, etc). Ataxia improves over a few weeks to a few months. Prognosis for complete recovery is excellent.
Where do 60% of all childhood brain tumors arise?
Brainstem or cerebellum
What is the most common brain tumor of childhood?
What grade is it?
Cerebellar pilocystic astrocytoma. Low grade (WHO grade I)
What are the radiologic features of the cerebellar pilocystic astrocytoma?
Pathology features?
Radiologic: Cyst with an enhancing mural nodule.
Pathology: Rosenthal fibers (eosinophilic and corkscrew shape)
Treatment of cerebellar pilocytic astrocytoma? Prognosis?
Surgery +- radiation&/or chemo.
Excellent prognosis.
What is the most common Malignant brain tumor in children?
Medulloblastoma.
A form of primitive neuroectodermal tumor (PNET)
Where does the medulloblastoma arise?
Midline (vermis and 4th ventricle roof). It can compress the 4th ventricle causing hydrocephalus (increasing ICP).
Symptoms of medulloblastoma?
Truncal ataxia, gait disturbances, increased ICP.
Pathology of medulloblastoma?
Rosettes or perivascular pseudorosettes.
Treatment of medulloblastoma? Prognosis?
Surgery+radiation+chemo.
Prognosis: 50-85% 5year survival.
The most common inherited ataxia? It’s genetic inheritance pattern and gene?
Friedreich’s Ataxia.
Autosomal recessive. Expanded GAA triplet repeat in FRDA gene that encodes frataxin.
Mechanism: suppressed gene expression, decreased frataxin levels, iron accumulation, oxidative stress, degeneration of PNS, CNS, and cardiomyopathy.
Age of onset of Freidrich’s ataxia?
Puberty - before 25.
Clinical features of Freidrich’s ataxia? Prognosis?
Progressive sensory ataxia. Progressive leg weakness. Impaired vibration, proprioception. Areflexia of lower extremities. Occulomotor abnormalitiesa and vision problems. Dysarthria. Sensorineural hearing loss. DM, Hypertrophic cardiomyopathy, scoliosis. Whealchair bound in 10yrs.
Chronic ataxia disease that presents in early childhood (2yrs)? Inheritance pattern?
Ataxia-Telangiectasia (AT).
Autosomal Recessive: Mutated ATM gene. ATM protein is involved in cell cycle control and DNA repair.
Clinical features of ataxia-telangiectasia?
Occulomotor apraxia: Inability to initiate saccades - child uses thrusts of the head in order to position eyes on target.
Occulocutaneous telangiectasias.
Recurrent sinopulmonary infections: decreased immune function.
Increased risk of malignancy: lymphoma, leukemia, brain tumor…Do NOT irradiate them.
Labs changes in ataxia-telangiectasia? Prognosis?
Increased alpha-fetoprotein.
IgA deficiency.
Live into early adulthood.
