Blackouts, Seizures + Epilepsy Flashcards
A blackout is a transient loss of consciousness. Collapse is an abrupt loss of postural tone (with our without transient LoC).
What is syncope?
- transient loss of consciousness (partial or complete)
- caused by global impairment of cerebral perfusion
- causing collapse
- spontaneous complete recovery
What are causes of blackout?
- neurological → epilepsy, stroke, TIA, tumour
- cardiovascular → vasovagal syncope, situational syncope, carotid sinus syncope, stokes-adams attack (arrythmias), orthostatic hypotension
- other → hypoglycaemia, anxiety, drop attacks, factitious, hyponatraemia + hypocalcaemia
What is a seizure?
- an acute change in neurological function produced by abnormal synchronous activity in the cerebral cortex
- epilepsy is having a predisposition to having seizures
- >more than 5 mins amnesia = strong marker
What are causes of seizures?
- infection → meningitis, encephalitis, cerebral abscess
- vascular → stroke, haemorrhage, venous thrombosis
- trauma → traumatic brain injury
- endo/met → hypoglycaemia, hypocalcaemia, hypomagnesaemia, uraemia, hyper/hypothyroidism
- toxic → alcohol, BDZ withdrawal, most rec drugs
What are acute provoked seizures?
- single seizures w/ underlying cause
- eg. trauma, hypoglycaemia, hyponatraemia, high fever, alcohol/drug abuse
What is the definition of epilepsy?
- at least 2 unprovoked (or reflex) seizures occurring more than 24hrs apart
Epileptic seizures may be classified as focal, generalised or unknown onset w/ subcategories of motor, non-motor (absence), with retained or impaired awareness for focal seizures.
The basic classification of epilepsy has changed in recent years. The new basic seizure classification is based on 3 key features.
What are these 3 key features?
- where seizures begin in the brain
- level of awareness during a seizure
- other features of seizures
What causes epilepsy?
- idiopathic → most common!
- structural → cortical scarring, SOL, developmental, stroke, tumour
- other → SLE, sarcoidosis, tuberous sclerosis
Generalised seizures affect your whole brain. During most of these seizures the person loses consciousness.
What are the two main types that generalised seizures can be classified into?
-
Motor onset:
- tonic-clonic + variants
- tonic
- atonic
- myoclonic
- myoclonic-atonic
- epileptic spasms
-
Non-motor onset:
- typical absence
- atypical absence
- myoclonic absence
- absence w/ eyelid myoclonia
What are tonic-clonic seizures?
- bilateral symmetric generalised motor seizures
- loss of consciousness
- tonic ⇒ bilateral increased tone (secs-mins)
- clonic ⇒ bilateral sustained rhythmic jerking
- tongue biting, incontinence, drowsy, confused, myalgia, headache
What are atonic seizures?
- sudden loss of muscle tone
- without apparent preceding myoclonic or tonic features
- very brief (<2seconds)
- may involve head, trunk, limbs
- often occur in indivdiuals w/ intellectual impairment
- can cause drop attacks
What is a myoclonic seizure?
- sudden jerk of limb, face or trunk
- may suddenly be thrown to the ground
- have violently disobedient limb
- tend not to black out
- occur in morning
What is an absence seizure?
- appear to be staring blankly into space
- unaware of surroundings + mildly confused after
- usually only last a few seconds
- eyelid fluttering + head flopping
- happen commonly in children + teenagers
- don’t usually continue into adulthood
- previously known as ‘petit mal’ seizures
Focal seizures originate within networks linked to one hemisphere and often are seen with underlying structural disease.
What is the new classification of focal seizures?
- aware or impaired awareness
- motor-onset
- non-motor onset
- focal to bilateral tonic-clonic seizure
Temporal lobe is the most common area for focal seizures. What are features if originating from the temporal lobe?
- automatisms: eg. funny hand movement, lip smacking
- dysphagia
- deja vu
- emotional disturbances
- delusional behaviour
- bizarre associations eg. cans make me pass out
How do focal seizures originating from the frontal lobe present?
- motor features eg. peddling
- jacksonian movement → clonic movements that move proximally eg. hand up arm
- motor arrest
- subtle behaviour changes
- dysphagia
- post-ictal Todd’s palsy
How do focal seizures arising from the parietal and occipital lobes present?
- parietal → sensory disturbances eg. paraesthesia, motor symptoms
- occipital → visual phenomena eg. flashes/floaters
Epilepsy is primarily a clinical diagnosis. What investigations can be done for suspected epilepsy?
- bloods → rule out reversible causes
- ECG
- EEG → interictal not very sensitive, repeating improves stats, sleep EEG even better, ambulatory
- MRI → if suspected focal
- 1st fit → neurology referral
There are now >25 UK licensed anti-epileptic drugs.
What are some of the 1st line medications?
- carbamazepine
- lamotrigine
- valproate
- levetiracetam
Common SEs: CNS (sedation, unsteadiness, diplopia) / weight gain or loss / behavioural / nausea + diarrhoea
~50% of patients with newly diagnosed epilepsy will become seizure-free with the first anti-epileptic drug (AED) prescribed.
Choice of medications is tailored to individual taking into account complex web of what factors?
- efficacy
- tolerability
- drug/comorbidity interactions
- remember, many AEDs including phenytoin, carbamazepine + topiramate are inducers of P450 enzyme
- caution when co-prescribing w/ warfarin or OCP
- pregnancy considerations
Monotherapy is preferable + increases probability of compliance, “start low + go slow”
Which anti-epileptic drugs are best for the different types of seziures?
- focal seizures → lamotrigine or carbamazepine
- focal seizures + migraines → topiramate or valproate
- generalised → valproate or lamotrigine
- absence → ethosuximide or valproate
- co-existing mood disorder → carbamazepine, lamotrigine or valproate
Choice of antiepileptic drug (AED) should be based on the likelihood of pregnancy in the near future. The latest data available on teratogenicity should be consulted and should play an important role in AED choice.
What anti-epileptic drugs are safer in pregnancy?
- oxcarbazepine
- lamotrigine
- levetiracetam
avoid: valproate, phenytoin, topiramate, phenobarbital
What is status epilepticus?
- seizure or series of seizures lasting more than 30 minutes without regaining full consciousness in between
- emergency treatment should commence after 5 minutes
- convulsive status epilepticus is the most severe type - mortality 20%
What is the general (not drug) acute management of status epilepticus?
- secure airway if possible / ABC
- attach monitoring → BP, ECG, oximetry
- give 100% O2
- protect patient’s head
- obtain IV access
- bloods to send off → glucose, lactate, pH, WCC, electrolytes, TFTs, AED level
- correct abnormalities as per, esp consider:
- 10ml pabrinex (thiamine)
- 50% dextrose
What is the immediate drug management of status epilepticus?
Oh My Lord, Phone The Anaesthetist
- Seizure >5mins: Slowly IV lorazepam 4mg for adults (100 mcg/kg for _<_11 yr olds)
- if no IV → rectal diazepam 10mg or buccal midazolam 10mg
- Seizure persists after 10 mins of first benzo: 2nd dose of benzo (IV lorazepam)
- Seizure persists after 10 mins of 2nd benzo: IV phenytoin 20mg/kg @ 50mg/minute, warn anaesthetist, can give phenobarbital
- If seizure persits after 20 mins: call anaesthetist, intubate, start propofol or thiopental
What are the rules in regards to driving and seizures?
- if you have a driving licence, and have a seizure of any kind, you must stop driving and tell the DVLA
- unless doctors consider that your seizures are likely to meet the criteria for permitted or provoked seizures, pt should fill in a ‘Declaration of Surrender for Medical Reasons’ form and return licence to the DVLA
- if don’t return license → license revoked + fined
- doctors can break confidentiality but should inform pt first
- normal licenses (epilepsy) → to drive, pt has to have been completely free of seizures for 1 year +/- AEDs
- normal license, isolated seizure → seizure-free for 6months
- lorries, buses, minibus drivers (epilepsy) → to drive, need to be seizure free, without AEDs for last 10 years + DVLA satisfied not likely to have any more seizures
- lorries etc isolated seizure → seizure-free for 5 years
