Epilepsy & LoC Flashcards
What are the classical features of a generalised (tonic-clonic) seizure?
Aura
LoC
Tonic phase (body rigid for 1min, tongue biting, incontinence)
Clonic phase (gen convulsion, frothing of mouth, rhythmic jerking, sev mins)
Post ictal phase (drowsiness/confusion/coma for sev hrs)
What are the three main types of syncope?
Vasovagal/cardiogenic syncope
Post hypotension
Post-prandial hypotension
What causes vasovagal syncope?
Due to sudden reflex bradycardia/peripheral vasodilation
What are the features of vasovagal syncope?
Occurs in response to standing/fear/venesection/pain
Pt unconscious <2mins
Recovery rapid, no treatment required
What is postural hypotension?
Drop in systolic BP of 20mmHg on standing from sitting/lying
What causes postural hypotension?
Pooling of blood in legs due to gravity
What factors increase the risk of postural hypotension?
Fluid depletion
Age-related autonomic dysfunction
Polypharmacy
What is post-prandial hypotension?
Drop in systolic BP of 20mmHg (or diastolic of 10mmHg) after eating
What causes post-prandial hypotension?
Pooling of blood in splanchnic vasculature
What are the less common causes of syncope?
Carotid sinus syncope (excessive vagal response)
Anaemic syncope
Micturition syncope
Coughing/exertion syncope
What features distinguish seizures from syncope?
Witness account of jerking movements, incontinence, post-episode confusion & amnesia = SEIZURE
Cardiac evaluation can detect risk factors for syncope
What investigations are appropriate in a pt w/ recurrent syncope?
Bloods - FBC, U&Es, glucose Lying/standing BP, tilt-tabel tests ECG/24hr tape (heart block, arrhythmias, long QT) EEG Echo/CT head
What advice must be given to all pts w/ recurrent syncope?
Do not drive until cause found
What is a seizure?
Convulsion/transient abnormal event resulting from paroxysmal discharge of cerebral neurones
What is epilepsy?
Continuing tendency to have seizures even if a long time separates the attacks
Affects 1% of population
What is a partial seizure?
Single focus of electrical activity
- simple partial
- complex partial
What are the features of a simple partial seizure?
No impairment of consciousness, single limb jerking w/ sensory aura (pattern depends on lobe involved)
- Temporal (lip smacking, chewing)
- Frontal (motor movements, speech arrest, Jacksonian march)
- Parietal (sensory disturbances, tingling/numbness
- Occipital (visual disturbances)
What are the features of a complex partial seizure?
Consciousness impaired at some stage
What is Todd’s paralysis?
Temporary paresis of originally affected limb after a partial seizure
What are the features of Temporal Lobe epilepsy?
Classical aura w/ sense of fear/deja-vu/hallucinations
Confusion/anxiety
Automatisms (lip smacking/chewing)
What are generalised seizures?
Widespread focus of electrical activity across both hemipsheres
- absence
- tonic-clonic
- tonic
- clonic
- myoclonic
- atonic
What are the features of absence seizures?
<10secs of LoC in 4-10yrs, more common in girls
Stimulated by hyperventilation/flashing lights
Remit by puberty, predispose to adult epilepsy
What are the features of tonic seizures?
Extended/flexed trunk
What are the features of clonic seizures?
Jerking
What are the features of myoclonic seizures?
Brief, shock like movements
What are the features of atonic seizures?
Sudden drop to the floor
What are the 2o causes of epilepsy?
Structural (trauma, SoL, stroke, SLE, AVMs)
Developmental (CP)
Metabolic
-hypo/hyper (glycaemia, calcaemia, natraemia)
-liver disease
Drugs (withdrawal, cocaine, TCAs, SSRIs, ciprofloxacin)
Infection (encephalitis, HIV, syphilis)
What is the immediate first aid treatment of a patient having a generalised seizure?
Place pt in recovery position
Remove harmful objects in location
Rectal dizepam
What should be done if the seizure lasts >3mins (status epilepticus)?
ABCDE IV Lorazepam (4mg bolus) Finger prick glucose (IV glucose 50ml of 50%) IV Pabrinex (if alcoholism) Preg test IV Phenytoin (if seizures persist, 15mg/kg) Continue intubation (anaesthetic review) CT/LPs/cultures
What are the possible causes of status epilepticus?
Epilepsy Hypoxia Stroke Brain injury Metabolic derangements Infections Eclampsia Drug withdrawal/toxicity
What is the prognosis of status epilepticus?
Mortality 10%
What investigations are appropriate in suspected epilepsy?
Bloods - FBC, U&Es, LFTs, Ca, Mg, glucose
Head CT/MRI
EEG
When is treatment for epilepsy started?
After two seizures, if organic causes ruled out
What is the goal of epilepsy treatment?
Control seizures w/ lowest possible dose w/ fewest side effects
-achieved in 70%
What are the most common triggers for epileptic seizures?
Lack of sleep Alcohol/drugs Hypoglycaemia Caffeine Stress Flashing lights
What medications are used to treat generalised seizures?
1st line - Valproate, Lamotrigine (if female of childbearing age)
Adjuncts - Clozabam, Carbamazepine, Levetiracetam
Ethosuxamide if absence seizure
What medications are used to treat partial seizures?
1st line - Carbamazepine, Lamotrigine (if female of childbearing age)
Multiple adjuncts used
How does Valproate work?
Potentiates GABA
Causes Na channel blockade
What are the common side effects of Valproate?
Rash/hair loss Sedation/wt gain Tremor Birth defects Thrombocytopenia Liver damage
How does Lamotrigine work?
Blocks Na channel
Reduces glutamate release
What are the common side effects of Lamotrigine?
Mild sedation
Bone marrow toxicity
How does Carbamazepine work?
Na channel blocker
What are the common side effects of Carbamazepine?
Rashes Dizziness Double vision Agranulocytosis Birth defects Liver damage Induces metabolism of itself/other drugs
How does Phenytoin work?
Voltage dependent blockage of Na channels
What are the common side effects of Phenytoin?
Gum growth
Nystagmus
Enzyme induction
Why does Phenytoin require therapeutic monitoring?
Zero order kinetics
Disproportionate increases in plasma concentration
What are the serious side effects common to all anti-epileptic drugs?
Leucopenia
Rashes
Steven-Johnson Syndrome
Toxic Epidermal Necrolysis
When can drug withdrawal be considered?
Seizure free for 2-4 years
- drug reduced in dose every 4wks
- pt stopping driving during withdrawal
What are the current laws regarding epilepsy and driving?
Pts must tell DVLA immediately/stop driving if had a seizure
-if pt was awake & LoC, license is revoked
Pts can apply for a new license if no seizures for 6mo after 1 seizure
-1yr after repeat attacks
If sleep-related epilepsy can drive if only had seizures while sleeping for 3yrs
