NEURO: Part 6 Flashcards
Define Huntington’s Chorea
- Cause of chorea and is a neurodegenerative disorder characterised by lack of inhibitory GABA
What is CHorea
Continuous flow of jerky, semi-purposeful movements, flitting from one part of the body to another
Interfere with voluntary movements but cease during sleep
Genetic cause of Huntington’s
AUTOSOMAL DOMINANT condition
At what age does HUNTINGTON’s present
Middle age
What type of symptoms are presented when huntington’s manifests
Prodromal phase (irritability, depression and incoordination)
Where does huntington’s mutation take place
CHROMOSOME 4 resulting in REPEATED EXPRESSION OF CAG sequence
- leads to translation of expanded polyglutamine repeat structure in huntington gene, protein gene product the function of which is unclear
How does symptom onset correlate with CAG repeats
More repeats = earlier symptoms
How many repeats are seen in middle aged men
36-55
How many repeats are seen in huntington’s childhood
60!
Pathophysiology caused by gene mutation in huntington’s
- Progressive cerebral atrophy with loss of neurones in DORSAL STRIATUM of basal ganglia - loss of GABANERGIC and CHOLINERGIC neurones
How does GABA effect Dopamine release
Loss of Gaba removes inhibition against dopamine = excessive thalamic stimulation and movements = chorea
Clinical presentation of Huntington’s
- PRODROMAL STAGE
- THEN CHOREA: Relentlessly progressive, jerky, explosive, rigidity INVOLUNTARY movements that cease when sleeping
CAN’T SIT STILL
- Dysarthria, dysphagia and abnormal eye movements
- BEHAVIOURAL CHANGES: Depression, anxiety and aggression + apathy
- Dementia (+ associated seizures)
What causes death in huntington’s
DEMENTIA within 15 years of diagnosis = infections
Differential diagnosis
CAUSES OF CHOREA:
- Sydenham’s chorea
- Creutzfeldt-Jakob Disease (prion)
- Wilson’s disease
- SLE
- Stroke of basal ganglia
How is huntington’s diagnosed
- Genetic testing
2. CT/MRI
What will genetic testing show in huntington’s
- CAG REPEATS
What would CT/MRI
CAUDATE NUCLEUS atrophy and increased size of frontal horns of LATERAL VENTRICLES (sign of brain matter destruction)
Can’t be used early on
How is huntington’s treated
- GENETIC COUNSELLING
- BENZODIAZEPINES
- SULPIRIDE (depresses nerve function)
- TETRABENAZINE (dopamine depleting agent)
- SEROXATE (SSRI antidepressant)
- HALOPERIDOL (antipsychotic medication)
- RISPERIDONE (to treat aggression)
What are primary causes of headache examples
- MIGRAINES
- CLUSTER HEADACHES
- TENSION HEADACHE
What are cluster headaches
Severe headaches around the eye
What are tension headaches
Headache effecting both sides of the head due to environmental stresses
What causes secondary headaches
- UNDERLYING CAUSES:
HIV FEVER THUNDERCLAP HEADACHE SEIZURE SUSPECTED MENINGITIS SUSPECTED ENCEPHALITIS RED EYE HEADACHE + NEW FOCAL NEUROLOGY (papilloedema(
Define Migraine
- Recurrent throbbing headache often proceeded by aura and associated with nausea, vomiting and visual changes
What kind of headache are migraines
EPISODIC
In what gender are migraines common
FEMALES
How does severity of headaches change with age
DECREASES
Causes of migrianes
CHOCOLATE C - Chocolate H - Hangovers O - Orgasms C - Cheese O - Oral Contraceptives L - Lie Ins A - Alcohol T - TUMULT (loud noise) E - Excersise
What nerve may cause migraines
Trigeminal nerve
Risk factors for migraines
- FEMALE
- AGE
- FAM HISTORY
Why do genetic factors have an effect on migraines
EFFECT NEURONAL-HYPER_EXCITABILITY
change sin brainstem blood flow lead stop unstable trigeminal nerve nucleus and nuclei in basal thalamus
Cortical spreading depression occurs
Results in release of vasoactive neuropeptides including calcitonin-gene-related peptide and substance P: causes neurogenic inflammation (vasodilatation and plasma protein extravasation leading to pain all over cerebral cortex
What is cortical spreading depression
Self-propagating waves of neuronal and glial depolarisation that spreads across cerebral cortex that causes aura of migraines and release of inflammatory mediators which impact trigeminal nerve nucleus
Clinical presentation of Migraine without aura
- TWO OF FOLLOWING:
- Unilateral
- Pulsing
- Moderate/severe pain in head
- Aggravated by routine physical activity
Nausea or vomiting during headache
Photophobia and Misophobia