Epilepsy Flashcards
Pathophysiology of seizure?
Clusters of brain neurons temporarily impaired -> paroxysmal electrical discharges -> symptoms
I.e. Bunch of neurons are firing at the same time
2 basic concepts of causes of seizure?
Too much excitation or too little inhibition
Explain how too much excitation can lead to seizure
Glutamate binds to NMDA receptors to open ion channel for calcium to allow calcium in to pass on electrical message. If patient has fast/long-lasting activation of NDMA receptors then can cause too much excitation and seizure
Explain how too little inhibition can lead to seizure
GABA binds to GABA receptors which opens ion channels that let chloride in which stops electrical message. Genetic mutations can occur in GABA receptor making it dysfunctional so can’t help inhibit signals
Main brain excitatory neurotransmitter and receptor
glutamate and NMDA receptor
Main brain inhibitory neurotransmitter and receptor
GABA and GABA receptor
What is epilepsy?
Seizure disorder of recurring and unpredictable seizures
Most common cause of epilepsy?
Idiopathic
Epilepsy prevalence
About 0.5% - very common
70% of epilepsy cases have no identified cause but 70% are well controlled with drugs. True/false
True
At what age does epilepsy normally present?
What age groups most common in?
Childhood/teenage years,
Old age
There is no genetic component of epilepsy. True/false?
False - 30% of patients will have first degree relative with epilepsy
List 6 causes for epilepsy
Trauma, Tumours, Infection, Vascular abnormalities e.g. stroke, Metabolic disturbance, Drugs
List 5 triggers that can push neuron excitation pas the seizure threshold in some patients with epilepsy
Sleep deprivation, Alcohol (both intake and withdrawal), Drug misuse, Flickering light, Infection/metabolic disturbance
Flickering lights are a trigger for only what type of epilepsy?
Primary generalised epilepsy only
Epilepsy is classified into partial and generalised epilepsy. What is the difference?
Partial epilepsy is focal seizures - confined to one area (hemisphere or lobe) of the brian,
Generalised epilepsy originate in the midbrain or brainstem and spread to whole brain
Partial seizures can be classified into simple partial & complex partial seizures. What is the main difference?
In simple partial seizures the patient remains conscious,
In complex partial seizures the patient has impaired consciousness
Simple partial seizure presentation?
Conscious!
Small area of brain affected so can be:
Sensory: strange sensations e.g. smell, auditory, taste
Motor: jerking movements of one limb,
Autonomic: sweating, pupil dilation, incontinence
Often aware & remembers
What is Jacksonian march?
When simple partial seizure causes jerking of one limb/muscle group which then spreads to another limb/groups
Complex partial seizure presentation?
Lose consciousness!
Often partial seizure symptoms precede as aura:
Sensory: Vertigo, auditory, visual,
Psychological: deja vu, emotional disturbance
Automatisms: lip smacking, chewing, swallowing, walking away
Impaired awareness & may not remember
What is Todd’s paralysis?
Weakness or paralysis of limbs may follow a seizure and lasts about 15hours, usually only one side
What are secondary generalised seizures and what type is it usually?
Partial seizures that spread to lower brain areas which then cause a generalised seizure, usually tonic-clonic
Generalised seizure types? (6)
Tonic, Atonic, Clonic, Tonic-clonic, Myoclonic, Absence seizures
Petit mal AKA
Absence seizures
Grand mal AKA
Tonic-clonic seizure
Most common type of generalised seizure?
Tonic-clonic
Tonic seizure presentation
All muscles contract and flex so patient usually falls backwards
Atonic seizure presentation
All muscles relax and go floppy so patient usually falls forward
Clonic seizure presentation
Convulsions: Muscles contract and relax
Tonic-clonic seizure presentation
Tonic phase for 10-60s - rigidity, epileptic cry, tongue biting, incontinence, hypoxia/cyanosis so no breathing
Then clonic phase for seconds-mins - convulsions, eye rolling, tachycardia, no/random breathing
Myoclonic seizure presentation
Short muscle twitches so different to clonic in that it is short jerking whereas clonic is periods of jerking
Absence seizure presentation
Unresponsive to stimuli but conscious, stares but only lasts around 15 seconds
Temporal lobe seizures AKA
Complex partial seizure
Absence seizures generally present at what age?
Childhood
What is status epilepticus?
Seizure that lasts >30mins or multiple seizures in which consciousness not recovered lasting >30mins
Why is status epilepticus a medical emergency?
Brain cells swell due to electrolyte imbalance and brain can herniate
Status epilepticus treatment? Initial, 1st, 2nd and other
Initial: ABC, emergency bloods (BG!!) +/- CT
After 10mins of seizures:
1st: benzodiazepines, if no response to 20mg then next
2nd: phenytoin
3rd: sodium valproate, phenobarbital.
Other: glucose if any suggestion hypoglycaemia, thiamine if any suggestion alcoholism or low nutritional status
Phenobarbital risk?
Can cause circulatory depression
Phenytoin risk?
Can cause severe cardiac arrhythmia
Epilepsy diagnosis need minimum of _ seizures
2
List 6 systemic disorders that can cause seizures
Uraemic encephalopathy, Hepatic encephalopathy, Electrolyte imbalances, Hypoglycaemia, Thiamine deficiency, Vitamin B12 deficiency
Investigations for seizure
ECG!!! Bloods: electrolytes, BG, FBC, LFTs, U&Es, serum calcium, CK (will be raised in true epileptics after tonic & clonic), MRI/CT for abnormalities, Urinalysis, EEG, Neuro exam,
Phenobarbital mechanism of action
Inhibits sodium channels so reduces action potential propagation
Phenytoin mechanism of action
Inhibits sodium channels so reduces action potential propagation
List 4 drugs that can cause epilepsy
Phenothiazines,
Isoniazid,
Tricyclic antidepressants,
Benzodiazepine withdrawal
List 6 types of metabolic disorders that can cause epilepsy
Uraemia, Hypoglycaemia, Hyponatraemia, Hypernatraemia, Hypocalcaemia, Hypercalcaemia
Primary generalised epilepsy first line treatment and alternative
First line: sodium valproate
Alternative as first line teratogenic: lamtrigine
Focal onset epilepsy treatment
Carbamazepine or lamotrigine
Postictal confusion in what type of seizures
May happen after partial complex seizures or generalised tonic-clonic
Why ALWAYS do ECG when seeming like seizure symptoms?
Could be long QT syndrome which can present like fit due to hypotension
When is EEG helpful? (4)
Whether someone is non-convulsive status or septic encephalopathy (old person confused),
Determine if someone having non-epileptic attack,
Epileptic surgical evaluation,
Epilepsy classification
Driving seizure and epilepsy rules
1st seizure: 6 months off road and 5 years for heavy duty vehicles
Epilepsy: can’t drive if seizure in last 1 year or changed meds in last 6 months, can drive when 1 year seizure free or 3 years during sleep only and 10 years seizure free & off medication for heavy duty vehicles
Which epilepsy types predominantly affect young people and which type predominantly older?
Young: generalised, usually spike-wave abnormalities on EEG
Old: partial/focal, because due to structural brain abnormality so more likely when older
When can focal epilepsy present in childhood?
Due to structural damage e.g. problem during birth or lots of febrile seizures
Common example of focal onset epilepsy
Complex partial seizures with hippocampal sclerosis
List 4 side effects of sodium valproate
Weight gain,
Teratogenic,
Hair loss,
Fatigue
Carbamazepine can make ________ epilepsies worse
Primary generalised epilepsies
Which 2 drugs useful for absence seizures?
Sodium valproate and Ethosuximide
What are functional attacks?
Psychogenic non-epileptic attack - like a seizure but not actually a seizure, not consciously mediated and often related to trauma etc.
Auras often precede seizures. True/false?
False - aura symptoms e.g. numbness, auditory are seizures in that area
3 common presentations of functional attacks and usual duration
- Attack with lots of motor activity
- Episodes of collapse with no movement
- Abreactive attacks e.g. fear, gasping & hyperventilation
Duration prolonged e.g. 10-20mins
List 4 anti-convulsant drugs that induce hepatic enzymes
Carbamazepine, phenytoin, phenobarbitol, topiramate
Women and anti-convulsants that induce hepatic enzymes considerations?
Can alter efficacy of combined oral pill so need dose adjustment,
Shouldn’t use progesterone only pill, depot or implants due to not being effective,
Morning after pill not adequate so need higher dose,
Older adults and anti-convulsants that induce hepatic enzymes considerations?
Can affect antihypertensive, cholesterol lowering, warfarin and chemotherapy efficacy
3 types of status epilepticus?
Generalised convulsive status epilepticus,
Non convulsive status, (conscious but confused and altered state)
Epilepsia partialis continua (continual focal seizures)
List 6 precipitants of status epilepticus
Severe metabolic disorders, Infection, Head trauma, Sub-arachnoid haemorrhage, Abrupt withdrawal of anti-convulsants, Treating absence seizures with carbamazepine
List 4 methods of death due to convulsive status that happen even before brain neuronal death.
Respiratory insufficiency and hypoxia, (due to choking)
Hypotension,
Hyperthermia,
Rhabdomyloysis
(Last 3 due to constant squeezing muscle complications)
When ICU for status?
If no response to drugs or if GCS really low (think benzo resp depression)
Partial status epilepticcus AKA non convulsive status diagnosis and treatment?
EEG to confirm diagnosis and then status treatment
Mechanism of action of benzodiazepines
Enhance GABA receptor
Child patient having fall to floor seizure indicates _____ whereas adult having fall to floor seizure indicates ____
Child indicates generalised atonic seizure whereas adult indicates non-epileptic attack
