Primary care - Neurological Flashcards
What is epilepsy?
a group of disorders characterised by a tendency for recurrent epileptic seizures (at least 2 unprovoked seizures occurring >24 hours apart)
What causes epilepsy?
2/3rd = idiopathic
1/3rd have identified cause:
Space-occupying lesion e.g. neoplasm
Head injury or cortical scarring from previous head injury
CNS infections
Stroke
Hippocampal sclerosis after febrile convulsion
Vascular malformations
What are some triggers of seizures?
Stress
Flashing lights
Alcohol/alcohol withdrawal
Describe the different elements of a partial seizure
Prodrome (hours/days) - change in mood/behaviour
Aura - focal seizure (commonly from temporal lobe), deja vu, strange smells, flashing lights
Post-ictal phase - headache, confusion, myalgia, temporary weakness, dysphasia
What is a focal seizure?
Start in one area of one side of the brain
Often seen with underlying structural disease
What are generalised seizures?
What are the different types and how do they present?
Involve both hemispheres of the brain
- Absence seizures - brief (less than 10 sec) pauses e.g. stares into space for 5 seconds then resumes talking, common in childhood
- Tonic-clonic - LOC, stiff limbs (tonic) then jerk (clonic). Tongue biting, incontinence. Post-ictal confusion and drowsiness
- Myoclonic - sudden jerk of a limb/trunk/face
- Atonic - all muscles relax and drop to floor, no LOC
What investigations should you do in epilepsy?
Anti-epileptic levels - check compliance
EEG
- Asymmetry or slowing suggests underlying structural abnormalities
- Sharp waves or spike wave complexes suggest neuronal hyperexcitability
- Many children with epilepsy will have a normal EEG
MRI - if focal onset or if seizures continue with medication
ECG - in all patients with altered consciousness
LP - if infection suspected
What are DVLA guidelines related to seizures?
Inform DVLA:
• 1st unprovoked seizure – stop driving for 6 months.
• Epileptic seizure – stop driving until seizure-free for 1 year.
• No HGV driving until seizure free and no meds for 10 years
What are 1st and 2nd line treatments for focal/partial seizures? What are important factors when prescribing AEDs?
1st line - carbamazepine or lamotrigine
2nd line - sodium valproate
Extra info:
Prescribe brand name - changing brand has 10% risk of worse seizure control
AEDs can only be prescribed following confirmed diagnosis (usually after second
seizure)
Patients on AEDs are entitled to free prescriptions
What are 1st line treatment for all generalised seizures?
Sodium valproate
What type of seizures should you avoid carbamazepine in ?
Absence
Myoclonic
can worsen them
Which anti-epileptic drug must be strictly avoided in pregnancy?
Which is preferred?
What must be thought about in terms of contraception?
Sodium valproate is the most teratogenic
Lamotrigine is preferred
Anti-epileptic drugs are P450 enzyme inducers so they make progesterone-only contraception unreliable.
Oestrogen-containing contraceptives lower lamotrigine levels so need increased dose.
What are the side effects of sodium valproate?
vALPROATE
Appetite increase - weight gain Liver failure Pancreatitis Reversible hair loss - grows back curly Oedema Ataxia Teratogenicity, thrombocytopenia, tremor Encephalopathy
Which drug should you avoid if taking sodium valproate?
Aspirin - it displaces sodium valproate from its binding sites which increases the adverse effects
When is carbamazepine contraindicated?
AV node conduction abnormalities - can cause AV block
Bone marrow depression - can cause agranulocytosis
Define stroke and TIA - specifying the differences
Stroke = sudden onset of focal/global neurological disturbance lasting over 24 hours. Causes irreversible cell damage + death.
TIA = less than 24 hour neurological dysfunction caused by ischaemia without evidence of acute infarction
What heart diseases particularly predispose you to ischaemic stroke?
AF
Infective endocarditis
Valve disease
Heart failure
What can cause a haemorrhagic stroke?
Rupture of an aneurysm
High blood pressure
Head injury
What is the most common cause of ischaemic stroke in young people?
Carotid artery dissection - usually caused by hitting their chin and hyperextending their neck, rupturing the carotid artery
What symptoms point more towards a bleed than ischaemia?
Meningism
Severe headache
Coma
Seizure
What does the ACA supply?
How would an anterior cerebral artery stroke present?
ACA supplies frontal + medial cerebrum
Contralateral leg weakness - foot drop
Contralateral leg sensory loss
Frontal lobe behavioural abnormalities
Facial sparing
What does the MCA supply?
How would an MCA infarct present?
Lateral cerebrum
Contralateral hemiparesis
Contralateral homonymous hemianopia if optic radiation involved
Dysphasia if dominant hemisphere
Visuospatial disturbance if non-dominant
What makes up the anterior circulation of the brain?
Internal carotid arteries
Middle cerebral artery
Anterior cerebral artery
How would a total anterior circulation stroke (TACS) present?
Hemiparesis (but with sparring of the forehead) Hemisensory loss Homonymous hemianopia Visuo-spatial deficit Dysphasia