Epilepsy Flashcards
What is the mangement?
- A-E assessment - hypoglycaemia is an important cause of seizures
- Clear airway and administer oxygen by mask - prevents HIE
- Establish IV access
- Administer bolus injection of intravenous benzodiazepine (e.g. lorazepam 10mg) over 2 minutes
The patient stops convulsing after Lorazepam 10mg IV and is now drowsy and probably post ictal. What do you do now?
- Check FBC, urea and electrolytes, glucose and calcium
- Blood gases
- ECG
- Take further history from husband
- Examine patient further
- Set up cardiac monitor and pulse oximetry
Blood screen is now needed (including calcium) once patient stabilised. History and further examination are essential.
Define epilepsy.
>2 seizures
Epilepsy is a recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifesting as seizures. Convulsions are the motor signs of electrical discharges.
Define seizure.
Ictus - paroxysmal synchronised cortical electrical discharges
How common is epilepsy?
Common affects 1% of population
Peak age of onset is in early childhood or in the elderly
What are the two types of seizures?
- Focal/Partial - localised to a specific cortical region. Used to be divided into simple partial and complex partial seizures which did not and did affect consciousness respectively.
- Generalised - affect consciousness; usually split into 5 types.
Describe the elements of a seizure (before/after).
Prodrome - experienced by some patients and may last hours to days; usually a change in mood/behaviour.
Aura - usually implies a focal seizure of the temporal lobe e.g
- strange feeling in gut
- deja vu
- strange smells
- flashing lights
Post ictally pt may experience
- headache
- confusion
- myalgia
- temporary weakness after focal seizure in motor cortex (Todd’s palsy)
- dysphasia
What is the aetiology of epilepsy?
Majority idiopathic - 2/3 of cases
Primary epilepsy seizures e.g. idiopathic generalised epilepsy, temporal lobe epilepsy, junvenile myoclonic epilepsy
Secondary seizures (symptomatic epilepsy)
- tumour
- infection (e.g. meningitis, encephalitis, abscess)
- inflammation (vasculitis, rarely MS)
- toxic/metabolic (sodium imbalance, hyper/hypoglycaemia,hypocalcaemia, hypoxia, porphyria, liver failure)
- Drugs (and withdrawal e.g. alcohol, benzodiazepines)
- Vascular (haemorrhage, infarction)
- Congenital anomalies (e.g. cortical dysplasia)
- Neurodegenerative disease (e.g. Alzheimer’s disease)
- Malignant hypertension or eclampsia
- Trauma
Common seizure mimics
- syncope
- migraine
- non-epileptiform seizure disorder (e.g. dissociative disorder)
What is the pathophysiology of epilepsy?
Seizures result from imbalance in the inhibitory and excitatory currents (e.g. Na+ or K+ ion channels) or neurotransmission (i.e. glutamate or GABA neurotransmitters) in the brain.
Precipitants include any trigger which promotes excitation of the cerebral cortex (e.g. flashing lights, drugs, sleep deprivation, metabolic) but often cryptogenic.
What are the key questions to ask in an epilepsy history?
- Rapidity of onset
- Duration of episode
- Any alteration of consciousness
- Any tongue-biting or incontinence
- Any rhythmic synchronous limb jerking
- Any post-ictal period
- Drug history (alcohol, recreational drugs)
Can be difficult to diagnose as there are 40 different types. All pts must be referred to specialist within 2 weeks if it’s a first seizure. Ask about previous funny turns/odd behaviour.
What are the subtypes of partial/focal seizures and how do they differ?
NB partial seizures - originate within one hemisphere
- W/o impaired consciousness (“simple”) - awareness N, with focal motor/sensory/autonomic/psychic symptoms. No post-ictal symptoms.
- W/ impaired consciousness (“complex”) - awareness impaired; most commonly arise in temporal lobe and have post-ictal confusion
- Evolving to bilateral, convulsive seizure (“secondary generalised”) - electrical disturbance of a partial seizure spreads widely causing gen seizure in 2/3 patients (typically convulsive)
What are the subtypes of generalised seizures and how do they differ?
NB generalised = no localising features, spread bilaterally quickly.
- Absence seizures(petit mal)- brief <10sec pauses LOC but maintained posture, present in childhood. Usually rolling eyes, staring or chewing.
- Tonic-clonic seizures (grand mal) - LOC, limbs stiffen (tonic), then jerk (clonic), post-ictal confusion and drowsiness. Assoc with tongue biting and faecal/urinary incontinence.
- Myoclonic seizures - sudden jerk of limb/face/trunk, may throw pt violently to the ground, or pt may have violently disobedient limb
- Atonic (akinetic) seizures - sudden loss of muscle tone causing a fall, no LOC
- Infantile spasms - common in tuberous sclerosis
??. Non-convulsive status epilepticus: Acute confusional state. Often fluctuating. Difficult to distinguish from dementia.
What is the recurrence rate of provoked vs unprovoked seizures?
Provoked = 3-10% e.g. if caused by trauma, stroke, haemorrhage, alcohol.
Unprovoked = 30-50%
What are the localising features of a focal seizure…
in the temporal lobe?
- Automatisms - complex motor phenomena with impaired awareness, varying from primitive oral (lip smacking, chewing, swallowing) or manual movements (fumbling, fiddling, grabbing), to complex actions.
- Dysphasias
- Deja vu (when everything seems strangely familiar) or jamais vu (strangely unfamiliar)
- Emotional disturbance e.g. sudden terror, panic, anger, elation, derealisation (out-of-body experiences)
- Hallucinations of smell, taste or sound
- Delusional behaviour
- Bizzare associations
What are the localising features of a focal seizure starting in the…
frontal lobe?
- Motor features such as posturing/peddling movements of legs
- Jacksonian march - spreading focal motor seizure with retained awareness, often starting with the face or a thumb
- Motor arrest
- Subtle behavioural disturbances (often diagnosed as psychogenic)
- Dysphasia or speech arrest
- Post-ictal Todd’s palsy
