Epilepsy Flashcards
What is epilepsy?
Common neurological condition characterised by recurrent seizures. Need to have had >2 seizures (>24 hrs apart) for a diagnosis of epilepsy.
What is a seizure?
excessive activity of cortical neurons resulting in transient neurological symtpoms
There are 2 types:
- Focal
- Generalised
What are the 2 types of seizures, explain them?
- Focal Seizure → seizure localised to specific cortical regions. May be complex (consciousness affected) or non-complex (consciousness not affected).
- Generalised Seizure → affects the whole brain and consciousness (lost immediately). Types include tonic-clonic, absence, myoclonic, atonic, tonic.
What is status epilepticus?
Seizure lasting longer than 5 mintues or ≥2 seizures within a 5-minute period without the person returning to normal between them. Tx with IV lorazepam or PR diazepam.
- Rule out hypoxia and hypoglycaemia (measuring blood glucose is key part in management of status epilepticus)
What are the different types of generalised seizures?
- Tonic-clonic: LOC, limbs stiffen (tonic) then jerk (clonic)
- Absence: brief pauses
- Myoclonic: sudden jerk of a limb, face or trunk
- Atonic: sudden loss of muscle tone causing fall (muscles relax)
- Tonic: muscles become stiff
Describe the pathophysiology of epilepsy
- 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
What are some possible causes of epilepsy?
- Structural causes:
- Cortical scarring e.g. head injury years before onset
- Developmental
- Space-occupying lesion
- Stroke
- Hippocampal sclerosis
- Vascular malformations - Other causes:
- Tuberous sclerosis
- Sarcoidosis
- SLE
- PAN - Non-epileptic causes of seizure
- Trauma
- Stroke
- Haemorrhage
- Raised ICP
- Alcohol or benzodiazepine withdrawal
- Metabolic disturbance: hypoxia, sodium imbalance, low calcium, glucose imbalance, uraemia
- Liver disease
- Infection e.g. meningitis, encephalitis
- High temperature
- Drugs e.g. tricyclics, cocaine, tramadol, theophylline
Summarise the epidemiology of epilepsy
COMMON
1% of the general population
Typical age of onset: CHILDREN and ELDERLY
What presenting symptoms of focal seizures (epilepsy) can be found in the history?
(post-ictal:period that begins when a seizure subsides and ends when the patient returns to baseline)
1. Frontal Lobe → motor convulsions, may show post-ictal flaccid weakness, jacksonian march (clonic movements starting in one extremity and moving proximally through the body) loss of consciousness, involuntary actions, rapid recovery
2. Temporal Lobe (most common type of partial seizure) → aura (weird smells, involuntary movements, deja vu, abdominal pain), lip smacking/plucking/grabbing (automatisms), post-ictal dysphasia and hallucinations
3. Occipital Lobe → visual disturbances (flashers and floaters)
4. Parietal Lobe → sensory issues (paraesthesia - tingling, numbness)
What presenting symptoms of generalised seizures (epilepsy) can be found in the history?
- Tonic-Clonic → vague symptoms before attack (eg. irritability), tonic phase (generalised muscle spasm - goes stiff and falls to floor), clonic phase (repetitive synchronous jerks - jerking limbs or loss of bladder control), urinary incontinence, tongue biting. Post-Ictal phase = impaired consciousness, lethargy, confusion.
- Absence → onset in childhood, loss of consciousness but maintained posture (don’t fall down). No post-ictal phase. Often begin abruptly without warning and end abruptly, with patients having no recollection of the episode. (Stare blankly into space). Tx with Ethosuximide.
- Myoclonic → convulsions without the muscle tensing (tonic phase). Sudden jerking of limb, trunk or face with preserved consciousness.
- “Juvenile myoclonic seizure”: There are 3 different types of seizures that people with JME may get. These are called myoclonic, tonic-clonic and absence seizures. All people with JME have myoclonic seizures. Myoclonic seizures cause sudden jerks of the muscles in the arms, legs, or whole body. - Atonic → sudden muscle relaxation causing patients to fall to the ground and then lay motionless. Can also result in incontinence.
- Tonic → muscle tensing without convulsions (clonic phase)
What investigations are used to diagnose/ monitor epilepsy?
- Clinical Diagnosis → 2 or more unprovoked seizures 24 hrs apart
- EEG → helps classify epilepsy and confirm diagnosis
- MRI/CT → look for structural, space occupying or vascular lesions that may cause midline shift
- Possibly if non-epileptic patient presenting with seizures
- Capillary Blood Glucose → exclude hypoglycaemia
- Electrolytes → look for hypocalcaemia and hyponatraemia
How is epilepsy managed?
Only start anti-convulsant treatment after >2 unprovoked seizures.
- 1st Line Focal Seizures → carbamazepine or lamotrigine (anticonvulsants)
- Carbamazepine ⇒ can cause SIADH and drowsiness, stevens-johnson syndrome.
- Lamotrigine ⇒ stevens-johnson syndrome = large blistering rash throughout the body. - 1st Line Generalised Seizures → sodium valproate (shouldn’t be used in pregnancy/women of childbearing potential/female children and adolescents).
- 2nd line = Lamotrigine or levetiracetam (if pregnant/woman of childbearing potential).
- Ethosuximide ⇒ can be used in absence seizures (after sodium valproate) - Status Epilepticus → IV lorazepam (hospital) or PR diazepam (community). If this doesn’t work give IV Phenytoin - SE: peripheral neuropathy, megaloblastic anaemia.
- Maximum of two doses of IV benzodiazepines can be administered. - DVLA
- 1st unprovoked seizure = 6 months off driving (if abnormal brain imaging or EEG then 12 months)
- No formal diagnosis of epilepsy after 1 seizure
What signs of epilepsy can be found on physical examination?
Depends on aetiology
Patients tend to be normal in between seizures
Identify possible complications of epilepsy
- Fractures from tonic-clonic seizures
- Behavioural problems
- Sudden death in epilepsy (SUDEP)
- Complications of anti-epileptic drugs:
- Gingival hypertrophy (phenytoin)
- Neutropaenia and osteoporosis (carbamazepine)
- Stevens-Johnson syndrome (lamotrigine)
Summarise the prognosis for patients with epilepsy
50% remission at 1 year
