Seizures Flashcards
What is a seizure?
A period when neurons are synchronously active when they shouldn’t be
- can be due to increased excitation or decreased inhibition
Discuss over excitation in epilepsy
Patients with epilepsy: long acting NMDA receptors – Ca2+ entry and depolarization
Discuss too little inhibition in epilepsy
Patients with epilepsy can have dysfunctional GABA receptors
- normally cause ion channels to open that allows Cl- influx
Discuss focal seizures
Focal aware (simple partial)
- small area of brain
- strange sensations
- jerking
- patient aware and remembers
Focal impaired awareness (complex partial)
- may not remember
*focal seizures can become generalised – termed secondary generalised
Discuss generalised seizures
- Tonic: stiff, flexed muscles, patient falls back
- Atonic: floppy, patient falls forward
- Clonic: violent convulsions
- Tonic clonic: most common
- Myoclonic: short muscle twitches
- Absence: loss and gain of consciousness with little outward sign
What is status epilepticus?
Seizure lasting >5mins
- usually tonic clonic
*treated with benzos to increase GABA transmission
What would the consequences be in a patient were to have a focal epileptic seizure in their frontal lobes?
- Bladder incontinence
- Disinhibition
- Expressive aphasia
- Dyspraxia
What would the consequences be in a patient were to have a focal epileptic seizure in their parietal lobes?
- Sensory disturbance
- Paresthesia (abnormal sensation)
e. g. warmth up one side of body
What would the consequences be in a patient were to have a focal epileptic seizure in their temporal lobes?
- Odd smell
- auditory/ visual hallucinations
- pallor, flushing, HR changes
- fidgeting, lip smacking
- emotional changes
- repetitive speech or speech arrest
What would the consequences be in a patient were to have a focal epileptic seizure in their occipital lobes?
Swirly multicoloured visual disturbance
Discuss pharmacology of epilepsy
- Diazepam: GABA receptor agonist
- Carbamazepine: anticonvulsant Na+ channel blocker
- Phenytoin: Na+ channel blocker - DO NOT GIVE FOR ABSENCE SEIZURES partial absence seizues
- Sodium valproate: Na+ channel blocker and GABA agonist
What is syncope?
Syncope is the commonest cause of episodes of loss of awareness. Simple faints or vasovagal syncopal attacks can usually be related to identifiable precipitants. Most often they occur on getting up quickly, or standing for prolonged periods, particularly if associated with peripheral vasodilation (e.g. during hot, stuffy weather, crowded trains or rooms, or are related to drug or alcohol use).
What is non-epileptic attack disorder (NEAD)
Non-epileptic attack disorder, previously known as pseudoseizures typically gives rise episodes of two broad types:
(a) attacks involving motor phenomena
(b) attacks of lying motionless.
Psychogenic nonepileptic seizures
AKA pseudoseizures
Features
- Pelvic thrusting
- Family member with epilepsy
- Crying after seizure
- Don’t occur when alone
- Gradual onset
Features favouring true epileptic seizures
- Tongue biting
- Raised serum prolactin
What are seizures?
Spontaneous, episodic, abnormal discharges of electrical activity in the brain
Epidemiology of epilepsy
- 0.5-1% prevalence in UK
- 450,000 people in UK
- 30,000 new diagnoses/ year
Peak in first presentations in children due to primary idiopathic epilepsies and developmental anomalies
Second peak in elderly due to acquired brain diseases e.g. stroke and dementia
Provoked vs unprovoked
- Unprovoked: spontaneous
- Provoked: can provoke a normal brain to have a seizure e.g. alcohol, electrolyte disturbance, recreational drugs
Risk factors causing predisposition for epilepsy
- Prematurity
- Complicated febrile seizures
- Genetic condition known to be associated with epilepsy e.g. tuberous sclerosis or neurofibromatosis
- Brain development malformations
- Family hx
- Head trauma, infections (meningitis, encephalitis), tumours
- Comorbidities e.g. cerebrovascular disease
- Dementia and neurodegen
- Recreational drugs or alcohol withdrawal
- Medication e.g. clozapine
- Electrolyte imbalances: hyponatremia is the most common cause as well as hypoglycaemia - basically any electrolyte derangement can precipitate a seizure