Epilepsy Flashcards
Define epilepsy
Define status epilepticus
**Epilepsy: **Recurrent tendency (minimum 2 episodes) to spontanous, intermittent, abnormal electrical activity in part of the brain, manifesting as seizures
Status epilepticus: State of seizure activity lasting for 30 min with no return to consciousness
Define convulsions
Motor signs of electrical discharges
Outline a typical seizure
- Prodrome - hours/ days previous a ‘change’ is noticed
- Aura - patient notices change
- Strange feeling in the gut, deja vu, strange smells, flashing lights
- Implies focal seizure from temporal lobe (normally)
- Aura - patient notices change
- Seizure occurs
- Post-ictally
- Headache, confusion, myalgia, sore tongue
- Todd’s palsy - motor cortex seizure causing temp. weakness
- Expressive dysphasia (frontal)/ Receptive aphasia (temporal)
Outline the different seizure classifications
Partial seizures - focal onset
- Simple - awareness unimpaired, no post-ictal symptoms
- Complex - awareness impaired, aura & post-ictal symptoms common
- 2ndary generalization - starts focal & spreads causing 2ndary generalised seizure
**Generalized seizure **- throughout cortex, no localising features
- Absence (petit mal)- brief (<30s) pauses, then continues
- Tonic-clonic (grand mal)- loss of consciousness, limbs stiffen (tonic), then jerk (clonic), post-ictal confusion
- Myoclonic - sudden jerk of limb, face or trunk
- Atonic (akinetic) - sudden loss of muscle tone (no LOC)
- Infantile spasms
What are the causes of epilepsy & seizures?
What are precipitating factors?
- Idiopathic (2/3, familial)
- **Structural **(1/3)
- CVA
- Space-occypying lesion
- Head injury (particularly when LOC >30min + structural findings)
Others causes of seizures;
- Alcohol/ benzodiazepine **withdrawal **(& binging)
- Meningitis/ Encephalitis
- Drugs: phenothiazines, isoniazid, tricyclic antiDs
-
Metabolic:
- Hypoxia - O2 sats
- ↑↓Na+- electrolytes
- ↑↓**Glucose **- blood glucose
- ↓Ca2+ - blood calcium
- Ureaemia - urine biochemistry
- Liver/ kidney disease - LFTs/ U&Es
Precipitating factors;
- Sleep deprivation, alcohol & medications lower threshold
- Peak during ovulation/ 2nd half of cycle
How do you investigate & diagnose epilepsy?
-
Electroencephalograph (EEG)
- When Hx suggests seizure is epileptic in origin
- Neuroimaging: MRI > CT
-
Structural abnormalities
- Focal? Medication failure?
-
Structural abnormalities
- Bloods
- Hypoxia - O2 sats
- ↑↓Na+ - electrolytes
- ↑↓Glucose - blood glucose
- ↓Ca2+ - blood calcium
- Ureaemia - urine biochemistry
- Liver/ kidney disease - LFTs/ U&Es
- 12-lead ECG
How would you localise a partial (focal) seizure?
-
Temporal - bizzare
- Automatisms - complex motor phenomena
- Emotion - hippocampal areas
- Smell/ tast - uncal areas
- Receptive aphasia - Wernicke’s area
- Delusional behaviour
-
Frontal
- Motor
- Jasksonian march [distal limb to ipsilateral face]
- Expressive Dysphasia - Broca’s area
- Post-ictal Todd’s palsy
-
Parietal
- Sensory
-
Occipital
- Visual
Outline the long term management of epilepsy?
Anti-Epileptic Drugs (AED)
- Absence - Sodium valproate (SV) (or Ethosuximide ⇒Lamotrigine)
- Generalized tonic-clinic - SV (⇒Lamotrigine)
- Myoclonic - SV (⇒Levetiracetam)
- Atonic - **SV **(⇒ Lamotrigine)
- Partial - Carbamazepine (⇒ sodium valproate or lamotrigine)
- Drug resistant: Levetiracetam, topiramate, zonisamide
+ supplementary Psychological interventions
Surgery…
Outline the mechanism of action of Sodium Valproate
Anticonvulsant;
- Blocks Na+ channels (weakly)
- Inhibits GABA deactivators
- Promotes GABA synthesis?
Outline the mechanism of action of Lorazepam
Benzodiazepine
- Increases GABA effect’s by binding to allosteric site of GABA receptor
Outline the acute management of an epileptic seizure & status epilepticus
- 0-5min
- Airway - protect, insert airway if possible
- Breathing - high flow mask 10L/min
- Circulation - IV access, 02 stats
- Bloods
- Lorazepam 4mg IV bolus (diluted 1:1 with sodium chloride/ water) (⇒ Diazepam 10mg IV/ 2min) - monitor O2 sats
- Poor nutrition/ alcoholism
- Parenteral thiamine as Pabrinex IV 100mL/ 30min/ 8hrly
- 5-10min
- Repeat Lorazepam [max. 8mg]/ Diazepam [max. 30mg]
- 10-40min
- Phenytoin IV with cardiac monitoring
- Contact Neurology Registrar
- >40min
- Contact consultant
- MIU/ critical care
- Arrange other investigations (ie EEG)
What are the differential diagnoses for seizures?
-
Syncope!
-
Vasovagal
- Reflexive anoxic seizures (asystole due to trigger [pain, fear])
- Carotid sinus hypersensitivity
- **Cardiac **- arrythmias & mechanical valves
-
Electrolyte abnormalities
- ↑↓Na+
- ↑↓Glucose
- ↓Ca2+
- Ureaemia
- Orthostatic hypotension
-
Vasovagal
- Hyperventilation
What implications does epilepsy have on driving?
What are the laws regarding it?
- Following a seizure you must stop driving, inform DVLA & motor insurance company
- Group 1 (car/ motorcycle)
- Epileptic attack
- Stop driving for 1 year after attack
- If attack while sleeping must stop for 1 year also (unless for the past 3 years youve only had an attack while asleep)
- Must comply with treatment & check-ups
- First unprovoked seizure
- 6 months off unless evidence suggests risk
- Epileptic attack
- Group 2 (large goods)
- For epileptics
- 10 years preceeding license issue must have NO epileptic attacks & be on no medication
- First unprovoked seizure
- 5 years off driving unless evidence suggests risk
- For epileptics
What are complications of epilepsy?
- SUDEP
- Sudden unexpected death in epilepsy (no identifiable cause)
- 500 deaths each year
- Risk increases with inc. freq. & severity of seizures
- Accidents (obviously)
- Depression & anxiety more prevalent
- Women with epilepsy: osteoporosis, osteomalacia, fractures
Outline typical petit mal seizure
- Presentation
- Provocation
- Prognosis
Absence seizure;
- Child stops what they are doing, stares, then continues
- Provoked by hyperventilation
- 90% resolve by teens
- ⇒ Grand mal (tonic-clonic) & Juvenile myoclonic epilepsy