Epilepsy Flashcards
What is the definition of epilepsy?
A tendency to recurrent, usually spontaneous, epileptic seizures.
Who does epilepsy most commonly affect?
Any age but most common in infancy and old age
Generalised epilepsy presents in childhood and adolescence and most have genetic predisposition
What are some risk factors for epilepsy?
Genetic
Acquired brain injury
Metabolic
Toxic
Environmental
What is the pathophysiology of epilepsy?
Epileptic seizure is abnormal synchronisation of neuronal activity (usually excitatory with high frequency action potentials but sometimes predominantly inhibitory)
Interruption of normal brain activity
Usually brief (secs-mins)
What is primary generalised epilepsy?
Often presents in childhood/teens
Early morning jerks
Risk factors - sleep deprivation, flashing lights
What is focal onset epilepsy?
Underlying structural cause
Onset at any age
Hippocampal sclerosis can occur
What are the types of generalised seizures?
Tonic-clonic
Absence
Atonic (‘drop attacks’)
Myoclonic
What are the types of focal seizures?
Temporal lobe
Frontal lobe
Parietal lobe
Occipital lobe
What is a tonic-clonic seizure?
Loss of consciousness and tonic (muscle tensing) and clonic (muscle jerking) episodes
May have tongue biting, incontinence, groaning and irregular breathing
Prolonged post-ictal period where person is confused, drowsy, feels irritable/depressed
What is an absence seizure?
Typically in children and stop as get older
Patient becomes blank, stares into space and then abruptly returns to normal
Unaware of surrounding during episode and won’t respond
Lasts 10-20 seconds
What is an atonic ‘drop attack’ seizure?
Brief lapses in muscle tone, causing patient to fall
Don’t usually last more than 3 minutes
Consciousness retained
What is a myoclonic seizure?
Sudden brief muscle jerks of a limb, trunk, face
What is temporal lobe epilepsy?
Aura occurring in most patients:
- Rising epigastric sensation
- Psychic or experiential phenomena (eg deja vu)
- Hallucinations less common (eg auditory, gustatory, olfactory)
Seizures lasting around 1 min
- Automatisms (lip smacking, grabbing, plucking)
With or without impaired awareness/consciousness
What is frontal lobe epilepsy (motor)?
Head/leg movements
Posturing
Post-ictal weakness
Jacksonian march
What is parietal lobe epilepsy (sensory)?
Paraesthesia
What is occipital lobe epilepsy (visual)?
Floaters/flashes
What are some investigations for epilepsy?
ECG (rule out prolonged QT syndrome)
Imaging (MRIb)
EEG (generalised epilepsy shows generalised spike-wave abnormalities)
What are the principles for starting anti-epileptics?
Drug therapy only started after minimum two fits
Only use one drug at a time, begin with small dose and gradually increase until control is achieved, toxic affects occur, or max dose is reached
What are the first and second line drugs for generalised seizures in men?
1) Sodium valproate
2) Lamotrigine/levetiracetam
What are the first line drugs for generalised seizures in women of childbearing age?
Lamotrigine/levetiracetam
What are the first and second line drugs for focal seizures?
1) Lamotrigine/levetiracetam
2) Carbamazepine
What is the first and second line treatment for absence seizures?
1) Ethosuximide
2) Sodium valproate
3) Lamotrigine/levetiracetam
What anti-seizure drugs can exacerbate absence and myoclonic seizures?
Carbamazepine
Gabapentin
Phenytoin
Pregabalin
Lamotrigine (for myoclonic only)
What is the first and second line drugs for myoclonic seizures?
1) Sodium valproate
2) Levetiracetam
What is the driving advice for epilepsy?
If driver has seizure of any type, must immediately stop driving and inform the DVLA
First unprovoked epileptic seizure/single isolates seizure = 6 months no driving
Established epilepsy must be seizure free for at least 1 year
What is the definition of status epilepticus?
A seizure lasting >5 mins, or multiple seizures over 5 minutes with incomplete resolution
What are some precipitants of status epilepticus?
Severe metabolic disorders
Infection
Heady trauma
Sub-arachnoid haemorrhage
Abrupt withdrawal of anti-convulsants
Treating absence seizures with CBZ
What can status epilepticus cause?
Respiratory insufficiency and hypoxia
Hypotension
Hypothermia
Rhabdomyolysis
What are some investigations for status epilepticus?
Identify cause after stabilising patient
- Emergency blood tests +/- CT
How is status epilepticus treated?
1) 2x doses benzodiazepines
- Diazepam 10-20mg rectally
- Midazolam 10mg buccally
- Lorazepam 4mg IV
2) IV phenytoin/levitiracetam/sodium valproate
3) General anaesthesia with propofol/midazolam/thiopental sodium
- Continued for 12-24 hours after last seizure then dose tapered
Generally:
Give high concentration oxygen
Give glucose if hypoglycaemic
Give IV thiamine is suggestion of alcoholism/impaired nutritional status
Assess cardiac and respiratory function
