Transient Loss of Consciousness Flashcards
what is epilepsy?
tendency to have seizures = a transient episode of ABNORMAl electrical activity in the brain
what is the post-ictal period
prolong period of confusion, drowsiness, irritability and disorientation following a seizure
what is the pathophysiology of seizures?
look in notes for synapses and receptor notes
what are generalised tonic clonic seizures, and how are they managed?
- USUALLY starts on both sides of brain
LOC Tonic (muscle tensing) Clonic (muscle jerking) movements Tonic phase comes before clonic phase Tongue biting, incontinence, groaning and irregular breathing After seizure: post-ictal period
Management of tonic-clonic seizures:
First line: sodium valproate
Second line: lamotrigine or carbamezapine
what are focal seizures?
affects just ONE part of brain
starts in temporal lobes
Affect hearing, speech, memory and emotions
Various ways that focal seizures can present
Hallucinations
Memory flashbacks
Déjà vu
Doing strange things on autopilot
Management:
First line: carbamezapine (or lamotrigine)
Second line: sodium valproate or levetiracetam
what are absence seizures?
Typically in children
Patient becomes black, stares into space and returns to normal quickly
During episode: unaware of surroundings and won’t respond
Only lasts 10-20s
Most patients stop having absence seizures as they get older
Management:
Sodium valproate or ethosuximide
what are atonic seizures?
Drop attacks
Characterised by brief lapses in muscle tone
Usually lasts less than 3 minutes
Typically begins in childhood
Management:
1st line sodium valproate
Second line lamotrigine
what are myoclonic seizures (part of generalised)
Sudden brief muscle contractions like a sudden jump
Patient usually remains awake during the episode
Occur in various forms of epilepsy but typically happen children as part of juvenile myoclonic epilepsy
Management:
1st line: sodium valproate
Others: lamotrigine, levetiracetam, topiramate
what are infantile spasms?
West syndrome Rare disorder starting around 6 months of age Full body spasms = clusters Poor prognosis: 1/3 die by age 35 o First line: prednisolone o Second: vigabatrin
what are febrile convulsions?
seizures in children age 6m to 5y who have a fever simultaneously
not caused by neuro pathology
no lasting damage
but slight increase risk for future epilepsy diagnosis
what are alcohol withdrawal seizures and how do you manage or prevent them
patients w history of alcohol excess who suddenly stop drinking
seizures occur around 36h following cessation
give benzos following cessation of drinking to reduce the risk
what is the pathophysiology of alcohol withdrawal seizures
chronic alcohol consumption = enhances GABA and inhibits NMDA glutamate
withdrawal = opposite so inhibition of GABA is decreased and increased NMDA glutamate
what are non-epileptic seizures / seizure disorder
present with epileptic like seizures but no characteristic electrical discharges
patients may have a history of mental health problems or a personality disorder
what are other, rare causes of seizures?
migranous events
vestibular disorders
cerebrovascular disorders
sleep disorders
what investigations would you do for a seizure?
history EEG MRI brain ECG to exclude heart problems electrolytes, blood glc, blood cultures where sepsis or encephalitis is suspected
when do you offer an EEG and what is it?
electroencephalogram of brain
perform after 2nd simple tonic clonic seizure in adults, or 1 for kids
what is the DVLA advice for people with epilepsy?
6 months seizure free if isolated
or 12 months seizure free if epileptic patient
what is the aim of AEDs
to raise seizure thershold and reduce patients risk of having a seizure
what are the side effects of sodium valproate
Teratogenic – hence MUST be avoided in girls unless there are no suitable alternatives – make sure they are on contraception and will NOT get pregnant
Liver damage and hepatitis
Hair loss
Tremor
what are the side effects of carbamezapine?
Agranulocytosis
Aplastic anaemia
Induces the P450 system so there are many drug interactions
what are the side effects of phenytoin?
Folate and vitamin D deficiency Megaloblastic anaemia (folate deficiency) Osteomalacia (vitamin D deficiency)
what are the side effects of ethosuximide?
night terrors and rashes
what are the side effects of lamotrigine?
DRESS syndrome (life threatening skin rashes)
leukopenia
what is the mechanism of sodium valproate and benzos?
increases GABA activity in brain by reducing metabolism of GABA transaminase
also enhances GABA receptors
blocks sodium and calcium channels
what is the mechanism of action of lamotrigine?
blocks sodium channel in presynaptic membrane and also acts on calcium channels (so does pregabalin)
what is the mechanism of action of levetiracetam?
acts on synaptic vesicle 2 and inhibits discharge of NT onto synaptic cleft
what are some behaviours indicative of non-epileptic attack disorder? helps to differentiate from epilepsy
v gradual onset or termiantion
pseudosleep
discontinous
irregular activity like side to side movement, stuttering, weeping
unresponsiveness and eye closure
- non cyanosed, no incontinence
how do you treat acute seizures?
put patient on floor in recovery position if possible
something soft under head
note time and end of seizure
call ambulance if 1st seizure or lasting more than 4 mins
patients may have been prescribed benzos so family can administer
what is status epilepticus
medical emergency = seizures lasting more than 5 minutes or > 2 seizures within a 5 minute period without person returning to normal between them
what is the priority in management of a seizure and why
terminating it, bc prolonged = irreversible brain damage
how do you manage status epilepticus in a hospital?
Secure the airway
Give high-concentration oxygen
Assess cardiac and respiratory function
Check blood glucose levels
Gain intravenous access (insert a cannula)
IV lorazepam, repeated after 10 minutes if the seizure continues
If seizures persist then infuse IV phenytoin, consider intubation and ventilation, and ICU care
what do you do if a seizure cannot be stopped and it has been 45 minutes?
induction of general anaesthesia
what is syncope
defined as a transient loss of consciousness due to global cerebral hypoperfusion
rapid onset, short duration and spontaneous complete recovery
what are the main questions you ask in a syncope history?
pre syncopal symptoms (cold, dizzy, abnormal taste, deja vu)
what were you doing before
how did you feel after, and where did you wake up?
eye witness history: twitching, colour change
concurrent illness - fever, infection
secondary injuries
palpitations or chest pain
neuro symptoms
happened before?
FH cardiac problems or sudden death
3 ways of classifying syncope
reflex
orthostatic
cardiac
what is reflex syncope
vasovagal: triggered by emotion, pain or stress.
‘fainting’
ANS has a problem regulating BF to the brain
vagus nerve receives signal of pain or stress - stimulates the PNS which counteracts ANS and hence blood vessels relax
o situational: cough, micturition, gastrointestinal
o carotid sinus syncope
what is orthostatic syncope
primary autonomic failure: Parkinson’s disease, Lewy body dementia
secondary autonomic failure: e.g. Diabetic neuropathy, amyloidosis, uraemia
drug-induced: diuretics, alcohol, vasodilators
volume depletion: haemorrhage, diarrhoea
what is cardiac syncope
arrythmias, tachycardias
structural: valvular, MI, hypertrophy
PE
low BP
what changes would you see on an ECG in cardiac syncope
QRS complexes may suddenly stop or change during that specific period
Eye-roll and slump back is textbook characteristic
what are the primary causes of syncope?
dehydration, missed meals, extended standing in warm environment
what are the secondary causes of syncope
hypoglylcaemia anaemia infection anaphylaxis cardiac
what are the signs and symptoms of syncope
• Prodrome = remember in event or how you felt before • Hot or clammy • Sweaty • Dizzy and lightheaded • Vision going blurry or dark - falling to ground
what investigations would you do for syncope?
CV exam
• postural blood pressure readings: a symptomatic fall in systolic BP > 20 mmHg or diastolic BP > 10 mmHg or decrease in systolic BP < 90 mmHg is considered diagnostic
• ECG
• tilt table test
• 24 hour ECG
• Bloods: FBC for anaemia, electrolytes, blood glucose
what are the differences between seizures and syncope?
look at table in notes
how do you manage syncope
lifestyle: water, avoid missing meals etc
during episode: sit or lie down, water and food
