Epilepsy Flashcards
Definition of epilepsy
Sudden paroxysmal uncontrolled synchronous discharge of cerebral neurons which produces symptoms either visible to patient or observer
Excludes gradual onset and discharge without symptoms
Prevelance
0.7-0.8% - higher in developing countries
Most common epilepsy causes in children
Perinatal problems, genetic or congenital disorders
Most common epilepsy causes in adults
Trauma, alcohol abuse, drugs, brain infection
Most common epilepsy causes in elderly
Cerebrovascular disease and mass lesions
Pre and perinatal risk factors x4
Intrauterine infections (including rubella, toxoplasmosis) maternal drug abuse, irradiation in early gestation, severe perinatal trauma or anoxia
Trauma/surgery and epilepsy
Highest risk with depressed skull fracture, penetrating injury or intracranial haemorrhage
Can be early or late when chronic epilepsy is most common
Metabolic causes of epilepsy x5
Electrolyte: Hyponatraemia, hypocalcaemia, hypomagnesaemia and hypoglycaemia
Uraemia
Hepatic failure
Acute hypoxia
Porphyria
Main pathological cause of temporal lobe epilepsy
Hippocampal sclerosis -childhood febrile convulsions are big risk factor - can treat surgically if medical not effective
Drugs which increase risk of epilepsy - 6x medication
3 x poisoning
Phenothiazines, tricyclics, MAO inhibitors, amphetamines, lidocaine and nalidixic acid
Lead, CO, Mercury
Infectious/inflammatory causes of epilepsy x6
Encephalitis Meningitis Tuberculomas Cerebral abscess Neurosyphilis
Neurocysticercosis - tapeworm - in countries where it is epidemic - major cause of epilepsy
Circulatory cause of epilepsy
Anoxic encephalopathy due to cardiac arrest or respiratory arrest
Seizure triggers
Photosensitivity, stress, sleep deprivation
Partial (focal) seizure definition
Electrical discharge limited to one region of cortex. Simple = no LOA, Complex = LOA
Generalised seizure definition
Simultaneous involvement of both hemispheres always associated with LOC or LOA
Focal can become secondary generalised
Features of absence seizures
Age of onset typically 4-12 - rarely beyond adolescence
Family history in 40% of patients
30% get TC in adolescence
Loss of awareness and vacant expression for
Tonic Clonic seizures features
Prodrome - no warning or may be an aura including tingling
Sudden LOC and drop to ground
Epileptic cry
Tonic - body stiff, elbows flexed, arms extended, eyes open, jaw clenched, pupils dilated - about 10 seconds - associated with rapid neuronal discharge
Clonic - neuronal discharge slows, jerking of limbs, increasing size but decreasing frequency, eyes open and roll backwards, might bite tongue and have urinary/faecal incontinence - lasts about 1-2mins
Post-ictal phase - flaccid unresponsiveness, confusion and drowsiness (15mins-1hour), headache, feel exhausted for days after including muscle ache due to CPK
What are myoclonic jerks?
Momentary brief contractions of a muscle or muscle group - commonest disorder = benign juvenile myoclonic epilepsy - onset in puberty - typically in the morning and affecting the upper limb.
Family hx may be present as is hereditary
What are tonic seizures?
Stiffening of the body - sustained muscle contraction - no jerking afterwards just LOC
Atonic seizures?
Sudden collapse with loss of muscle tone and LOC
Frontal Lobe Seizures?
eg. Focal motor seizure - Jacksonian march from mouth or hand quite rare
Sometimes followed by Todd’s paralysis - local temporary paralysis of limbs
What is an adversive seizure ?
Conjugate gaze deviates away from epileptic focus and head turns away too with some frontal seizures
What happens in supplementary motor cortex seizures?
Can get more complicated stereotyped movements eg. cycling motion
Occiptal lobe seizures?
Uncommon - elementary visual hallucinations
Parietal lobe seizures?
Sensory cortex therefore paraesthesia or tingling in extremities or face
Features of complex partial seizure (temporal lobe seizure)?
Start with aura - rising epigastric feeling and nausea with a wide range of sensory disturbances:
- memory
- visceral (olfactory or gustatory eg. lip smaking)
- visual
- affective/emotional disturbance
Followed by period of complete or partial loss of awareness (1-2mins vs 10secs of absence seizure)
Loss of awareness occurs with automatisms and speech arrest
May be followed by a short-period of post-ictal confusion and headache
Causes of epilepsy.
50% cryptogenic, 10-20% genetic, 30-40% structural or metabolic
What are febrile convulsions?
Not typically epilepsy but are epileptic seizures
Can be simple or complex
Incidence of febrile convulsions and prognosis?
Affect 3% of between ages of 6 months and 6 years
Only 5% go on to have epilepsy
Medications which lower seizure threshold x2
Anti-malarials and antidepressants
Clinical discriminator between epilepsy and syncope x4 and 2 which occur in both
Injury and urinary incontinence occur in both
Prolonged recovery period, bitten tongue and stereotyped attacks = epilepsy
Colour change - pallor = syncope and cyanosis = epilepsy
EEG findings in epilepsy
50% presenting with epilepsy will have normal EEG inter-ictal
If drug induced sleep EEG, sleep-deprived EEG or prolonged/ambulatory EEG then 85% show activity
Recurrence risk after first seizure
70-80% will have 2nd seizure and highest risk during first 6months - majority who have second will continue to have seizures if not treated
Epilepsy and psychiatric illness
Same risk of psychiatric disease as other illnesses but increased risk of psychosis
Tonic-clonic drug treatment
1st line
- Sodium valproate
then 2nd
- Lamotrigine and Carbamazepine
Others
- Oxcarbamazepine
- Levetiracetam (Keppra)
Focal first line drugs
- Carbamazepine or Lamotrigine
Then
- Levetiracetam
- Sodium valproate
- Oxcarbamazepine
Myoclonic drugs
1st - valproate
2nd - clonazepam, lamotrigine
but not carbamazepine, gabapentin, phenytoin or oxcarbamazepine as these can make it worse (same as absence)
Absence treatment
1st line - Sodium valproate and ethosuximide
2nd - lamotrigine
not carbamazepine, gabapentin, oxycarbazepine, phenytoin etc
Juvenile myoclonic treatment
Sodium valproate
Two other treatment options - not drugs
Surgery
neurostimulation (vagal nerve or trigeminal - works in 10%)
Status epilepticus definition
Medical emergency
Continued seizure for 30mins or more - or two without recovery of consciousness
Can be convulsive, absence or focal
Prognosis and incidence of status epilepticus
Mortality 10-15%
50% occur with no previous history of seizures
Treatment of status epilepticus
Early: O2 and monitoring, lorazepam IV, midazolam buccal or diazepam rectal
Established (30-90mins):
Phenytoin IV or fosphenytoin
If ongoing:
Phenobarbitol or valproate
Last line: Paralyse and ventilate
SUDEP
Sudden unexplained death in epilepsy
Night time seizure could cause heart arrhythmia which will result in patient not waking up
More common in uncontrolled epilepsy & alcohol drinking
Valproate side effects
Valproate Appetite increase and weight gain Liver failure Pancreatitis Reversible hair loss (curly when grows back) Oedema Ataxia Teratogenicity, thrombocytopenia, tremor Encephalopathy (ammonia increase)
Lamotrigine side effects
Maculopapular rash - in 10%
1 in 1000 develop stevens-johnson syndrome /toxic epidermal necrolysis
Also diplopia, blurred vision, tremor, agitation vomiting, aplastic anaemia
Phenytoin side effects
No longer first line for epilepsy because of toxicity
Nystagmus, diplopia, tremor, dysarthria, ataxia
Keppra/levetiracetam side effects
Psychiatric common - depression and agitation
Carbamazapine side effects
Leucopenia, diplopia, blurred vision, imbalance, drowsiness, rash
Tonic and atonic seizure treatment
Valproate first line
2nd lamotrigine
not carbmazepine etc
Management of essential tremor
Propanolol first line
Primidone
