Epilepsy Flashcards
What is the definition of epilepsy?
A tendency to recurrent unprovoked seizures
You need to have had 2+ seizures for epilepsy to be diagnosed
What is the definition of a seizure?
Paroxysmal synchronised cortical electrical discharges
Types of seizures?
- Focal Seizure: seizure localised to specific cortical regions (e.g. temporal lobe seizure). These can be further divided into: (COMPLEX partial seizure: consciousness is affected and SIMPLE partial seizure: consciousness is NOT affected)
- Generalised Seizure: seizures that affect the whole of the brain. It also affects consciousness. There are different types of generalised seizure: Tonic-clonic, Absence, Myoclonic, Atonic, Tonic
Explain the aetiology and risk factors of epilepsy?
- Most cases are idiopathic
- Primary epilepsy syndromes (e.g. idiopathic generalised epilepsy)
- Secondary Seizures:
Tumour
Infection (e.g. meningitis)
Inflammation (e.g. vasculitis)
Toxic/Metabolic (e.g. sodium imbalance)
Drugs (e.g. alcohol withdrawal)
Vascular (e.g. haemorrhage)
Congenital abnormalities (e.g. cortical dysplasia)
Neurodegenerative disease (e.g. Alzheimer’s disease)
Malignant hypertension or eclampsia
Trauma
What are things that commonly look like seizures?
- Syncope
- Migraine
- Non-epileptiform seizure disorder (e.g. dissociative disorder)
What is the pathophysiology of seizures?
- Result from an imbalance in the inhibitory and excitatory currents or neurotransmission in the brain
- Precipitants include anything that promotes excitation of the cerebral cortex
- Often it is unclear why the precipitants cause seizures
Summarise the epidemiology of epilepsy?
- Common (affects 1% of general population)
- Typical age of onset = children and elderly
How to recognise the presenting symptoms of epilepsy?
-NOTE: try and obtain a collateral history from a witness as well as the patient
-Key features to consider when taking a history from a potential epilepsy patient:
Rapidity of onset
Duration of episode
Any alteration in consciousness?
Any tongue-biting or incontinence?
Any rhythmic synchronous limb jerking?
Any post-ictal abnormalities (e.g. exhaustion, confusion)?
Drug history (alcohol, recreational drugs)
What is the focal seizure presentation?
Frontal Lobe Focal Motor Seizure
- Motor convulsions
- May show a Jacksonian march (when the muscular spasm caused by the simple partial seizure spreads from affecting the distal part of the limb towards the ipsilateral face)
- May show post-ictal flaccid weakness (Todd’s paralysis)
Temporal Lobe Seizures
- Aura (visceral or psychic symptoms)
- Hallucinations (usually olfactory or affecting taste)
Frontal Lobe Complex Partial Seizure
- Loss of consciousness
- Involuntary actions/disinhibition
Rapid recovery
What is the presentation of generalised seizures?
Tonic-Clonic (Grand Mal)
- Vague symptoms before attack (e.g. irritability)
- Tonic phase (generalised muscle spasm)
- Clonic phase (repetitive synchronous jerks)
- Faecal/urinary incontinence
- Tongue biting (MAJOR)
- Post-ictal phase: impaired consciousness, lethargy, confusion, headache, back pain, stiffness
Absence (Petit Mal)
- Onset in CHILDHOOD
- Loss of consciousness but MAINTAINTED POSTURE
- The patient will appear to stop talking and stare into space for a few seconds
- NO post-ictal phase
Non-Convulsive Status
- Epilepticus
- Acute confusional state
- Often fluctuating
- Difficult to distinguish from dementia
Recognise signs of epilepsy upon physical examination?
Depends on aetiology
Patients tend to be normal in between seizures
What is a status epilepticus?
A seizure lasting 30+ mins or repeated seizure without recovery and regain of consciousness in between
Although the definition states that the seizure must last > 30 mins, treatment is usually initiated early (after around 5-10 mins)
Management of a status epilepticus?
-ABC approach
-Check GLUCOSE (give glucose if hypoglycaemic)
IV lorazepam OR IV/PR diazepam - REPEAT again after 10 mins if a seizure does not terminate
- If seizures recur following the next dose of lorazepam or diazepam, consider IV phenytoin - an ECG monitor is required (NOTE: other agents include phenobarbitone, levetiracetam and sodium valproate )
- If this also fails, consider general anaesthesia (e.g. thiopentone) - intubation and mechanical ventilation required
- Treat the CAUSE (e.g. hypoglycaemia or hyponatraemia)
- Check plasma levels of anticonvulsants (because status epilepticus is often caused by lack of compliance with anti-epileptic medications)
How would you treat recently diagnosed epilepsy?
- Only start anti-convulsant therapy after 2+ unproveoked seizures
1st line for focal seizures = Lamotrigine or Carbamazepine
1st line for generalised seizures = sodium valproate
- Start treatment with only one anti epileptic drug
- Other anti-convulsants: phenytoin, levetiracetam, clobazam, topiramate, gabapentin, vigabatrin
What other steps may be involved in the management of epilepsy?
-> Patient Education:
Avoid triggers
Use seizure diaries
Particular consideration for women of child-bearing age because the anti-epileptic drugs can have teratogenic effects
Be careful of drug interactions (e.g. AEDs can reduce the effectiveness of the oral contraceptive pill)
-> Surgery may be considered for refractory epilepsy
