Nervous System Flashcards
What are some of the different types of dementia?
- Alzheimer’s
- Parkinson’s-associated dementia
- Lewy-body dementia
- Vascular dementia
What symptoms does dementia cause?
Cognitive symptoms:
- Memory loss
- Difficulty thinking
- Language issues
- Loss of orientation
Non-cognitive symptoms:
- Psychiatric and behavioural problems
- Difficulties with daily activities
How is Alzheimer’s disease managed?
For cognitive symptoms
If mild-moderate disease:
Acetycholinesterase inhibitors
If moderate-severe disease:
NMDA glutamate receptor antagonist
What acetylcholinesterase inhibitors are available?
- Donepezil
- Galantamine
- Rivastigmine (used in Parkinson’s associated dementia)
What side-effects are associated with each of the acetylcholinesterase inhibitors?
- Donepezil - neuroleptic malignant syndrome (risk associated with concomitant antipsychotics)
- Galantamine - serious skin reactions, e.g. SJS. Should be stopped at first appearance of skin rash
- Rivastigmine - GI disturbances (withhold until resolved). Transdermal application associated with reduced side-effects.
What side-effects are all of the acetylcholinesterase inhibitors associated with?
Cholinergic side-effects (parasympathomimetics):
DUMB BELS
D = Diarrhoea U = Urination M = Muscle weakness / cramps / miosis B = bronchospasm
B = Bradycardia E = Emesis L = Lacrimation (teary eyes) S = Salivation / sweating
How are non-cognitive symptoms of dementia managed?
1) Antipsychotics - only for severe symptoms causing significant distress or if there’s an immediate risk to self or others.
MHRA states increased risk of stroke and death with antipsychotic use in elderly patents with dementia.
For extreme violence, aggression and extreme agitation, oral benzodiazepines or antipsychotics may be used. If IM needed: haloperidol / olanzapine / lorazepam can be used.
What is epliepsy?
A sudden surge of electrical activity of neurones in the brain. This causes seizures.
What can cause non-epileptic seizures?
- Organic factors, e.g. hypoglycaemia / fever
- Psychogenic, i.e. mental or emotional processes.
True or False - Most AED’s are given BD.
True.
Exceptions: phenobarbital, lamotrigine, perampanel and phenytoin.
What are the common AED’s?
- Phenobarbital
- Carbamazepine
- Gabapentin
- Pregabalin
- Lamotrigine
- Levetiracetam
- Phenytoin
- Sodium valproate
- Topiramate
What are the treatment options for focal seizures?
1st Line:
Lamotrigine / Carbamazepine
Alternatives:
Levetiracetam / Valproate / Oxcarbazepine
What are the treatment options for tonic-clonic seizures?
1st Line:
Valproate / Lamotrigine / Carbamazepine
What are the treatment options for absence seizures?
1st Line:
Ethosuxiumide / Valproate (high risk of tonic-clonic)
Alternative:
Lamotrigine
What are the treatment options for myoclonic seizures?
1st Line:
Valproate
Alternatives:
Topiramate / Levetiracetam
What are the treatment options for atonic / tonic seizures?
Valproate
Which AED’s are advised to be maintained on same brand?
Category 1:
- Carbamazepine
- Phenytoin
- Phenobarbital
- Primidone
Category 2: Based on judgement & patient consultation - Valproate - Lamotrigine - Clonazepam - Topiramate
Why should AED’s be withdrawn gradually?
Abrupt withdrawal can precipitate severe rebound seizures.
How should AED’s be withdrawn?
Gradually under specialist supervision. 1 AED should be withdrawn at a time if the patient is on combination therapy.
True or False - Patients with epilepsy are never allowed to drive? Explain.
False.
Patients will only ever be able to drive a car.
Patients need to be seizure free for at least 1 year.
Patients will be banned from driving when:
- Medication is being changed / withdrawn
- 6 months after last dose
- 6 months after 1st unprovoked seizure
Can AED’s be used in pregnancy?
Ideally no due to risk of teratogenicity.
Valproate - congenital malformations and long-term developmental disorders.
Increased risk of teratogenicity with carbamazepine, phenytoin, phenobarbital, primidone and lamotrigine.
Cleft palate risk with topiramate use in 1st trimester.
True or False - There’s an increased risk of suicidal thoughts and behaviour in patients taking AED’s.
True - symptoms can occur within 1 week of starting. Patients should report any mood changes, distressing thoughts or feelings about suicide or self-harm.
Side-effects of AED’s.
Skin Rashes
- Lamotrigine - SJS, toxic epidermal necrolysis. Higher risk with high initial dose, rapid dose increase and use of valproate.
Blood Dyscrasias
- Report any signs of infection, bruising or bleeding.
Eye Problems
- Vigabatrin - visual field defects.
- Topiramate - acute myopia with secondary ACG.
Encephalopathic Symptoms
- Vagabatrin - marked sedation, stupor and confusion with slow wave EEG.
Which AED’s are CYP450 inhibitors or inducers?
Inhibitors:
-Sodium valproate
Inducers:
- Carbamazepine
- Phenytoin
- Phenobarbital
What is the mechanism of action of phenytoin?
Binds to neuronal sodium channels in their inactive state which prolongs activity.
True or False - Phenytoin can be used in absence and myoclonic seizures.
False - they exacerbate these types of seizures and should be avoided.
What is the therapeutic range for phenytoin?
10-20mg/L
Is phenytoin highly or lowly protein-bound?
Highly protein-bound.