Epilepsy Flashcards
Definition (epilepsy)
· A tendency to recurrent unprovoked seizures
· You need to have had > 2 seizures for epilepsy to be diagnosed
Definition (seizure)
paroxysmal synchronised cortical electrical discharges
Types of seizure
o 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
· SIMPLE partial seizure: consciousness is NOT affected
o 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
Aetiology/Risk factors
· Most cases are IDIOPATHIC
· Primary epilepsy syndromes (e.g. idiopathic generalised epilepsy)
· Secondary Seizures
o Tumour
o Infection (e.g. meningitis)
o Inflammation (e.g. vasculitis)
o Toxic/Metabolic (e.g. sodium imbalance)
o Drugs (e.g. alcohol withdrawal)
o Vascular (e.g. haemorrhage)
o Congenital abnormalities (e.g. cortical dysplasia)
o Neurodegenerative disease (e.g. Alzheimer’s disease)
o Malignant hypertension or eclampsia
o Trauma
Things which look like seizures
o Syncope
o Migraine
o Non-epileptiform seizure disorder (e.g. dissociative disorder)
Pathophysiology of seizures
o Result from an imbalance in the inhibitory and excitatory currents or neurotransmission in the brain
o Precipitants include anything that promotes excitation of the cerebral cortex
o Often it is unclear why the precipitants cause seizures
Epidemiology
· COMMON
· 1% of the general population
· Typical age of onset: CHILDREN and ELDERLY
History taking
· 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:
o Rapidity of onset
o Duration of episode
o Any alteration in consciousness?
o Any tongue-biting or incontinence?
o Any rhythmic synchronous limb jerking?
o Any post-ictal abnormalities (e.g. exhaustion, confusion)?
o Drug history (alcohol, recreational drugs)
Presenting symptoms (focal seizures)
o 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)
o Temporal Lobe Seizures
· Aura (visceral or psychic symptoms)
· Hallucinations (usually olfactory or affecting taste)
o Frontal Lobe Complex Partial Seizure
· Loss of consciousness
· Involuntary actions/disinhibition
· Rapid recovery
Presenting symptoms (generalised seizures)
o 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
· Post-ictal phase: impaired consciousness, lethargy, confusion, headache, back pain, stiffness
o 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
o Non-Convulsive Status Epilepticus
· Acute confusional state
· Often fluctuating
· Difficult to distinguish from dementia
Signs on physical examination
· Depends on aetiology
· Patients tend to be normal in between seizures
Investigations
· Bloods o FBC o U&E o LFTs o Glucose o Calcium o Magnesium o ABG o Toxicology screen o Prolactin - shows a transient increase shortly after seizures
· EEG
o Helps to confirm diagnosis
o Helps classify the epilepsy
o Ictal EEGs are particularly useful (i.e. during a seizure)
· CT/MRI
o Shows structural, space-occupying or vascular lesions
· Other investigations
o If it is suspected to be a secondary seizure (e.g. due to infection)
Management plan (status epilepticus)
DEFINITION of Status Epilepticus: a seizure lasting > 5 mins or repeated seizure without recovery and regain of consciousness in between
o Treatment is usually initiated early (after around 5-10 mins)
o ABC approach
o Check GLUCOSE (give glucose if hypoglycaemic)
o IV lorazepam OR IV/PR diazepam - REPEAT again after 10 mins if seizure does not terminate
o 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
o If this also fails, consider general anaesthesia (e.g. thiopentone) - intubation and mechanical ventilation required
o Treat the CAUSE (e.g. hypoglycaemia or hyponatraemia)
o Check plasma levels of anticonvulsants (because status epilepticus is often caused by lack of compliance with anti-epileptic medications)
Management plan (newly diagnosed)
o Only start anti-convulsant treatment after > 2 unprovoked seizures
o FOCAL Seizure 1st Line: lamotrigine or carbamazepine
o GENERALISED Seizure 1st Line: sodium valproate
o Start treatment with only ONE anti-epileptic drug
o Other anti-convulsants: phenytoin, levetiracetam, clobazam, topiramate, gabapentin, vigabatrin
Surgery may be considered for refractory epilepsy
Management plan (patient education)
o Avoid triggers
o Use seizure diaries
o Particular consideration for women of child-bearing age because the anti-epileptic drugs can have teratogenic effects
o Be careful of drug interactions (e.g. AEDs can reduce the effectiveness of the oral contraceptive pill)
