S12 L1 Epilepsy Flashcards
What is a seizure?
Transient occurencer of signs or symptoms due to abnormal electrical activity in the brain leading to a disturbance of consciousness, behaviour, emotion, motor function or sensation
What is the pathophysiology of a seizure?
- Abnormal excessive excitation and synchronisation of a group of neurones in the brain
- This can be due to a loss of inhibitory signals (GABA) OR and excess of excitatory signals (Glutamate)
What are some causes of seizures?
- Genetic epilepsy syndromes (genetic differences in receptor structure)
- Exogenous activation of receptors e.g drugs and alcohol
- Changes in brain chemistry e.g drug withdrawal, metabolic changes like low glucose
- Damage to any networks e.g stroke or tumour knocking out inhibitory neurones
What are some signs and symptoms of seizures?
- Generalised have loss of consciousness, changes in muscle tone, tongue biting
- Tonic clonic have initial hypertonic phase then rapid clonus
- Post-ictal period
- Often aura before
What is the definition of epilepsy and what is the criteria that has to be met to fulfil this diagnosis?
- Tendency towards recurrent seizures unprovoked by a systemic or neurological insult. Due to abnormal hyperactivity in the brain
- At least 2 unprovoked (or reflex) seizures occuring more than 24 hours apart OR one unprovoked seizurte and a high recurrence risk (60% over 10 years)
What is a reflex seizure?
How can we classify seizures?
- Generalised: electrical spread across both hemispheres of the brain and result in a loss of consciousness. Absence and tonic-clonic seizures
Focal Onset: no loss of awareness mostly and the most common type of seizure
What are provoked seizures and how do we treat them?
- Seizure as a result of another medical condition
- Need to treat both the seizure and the underlying condition and unlikely to need ongoing AED treatment if cause treated
What are some differential diagnoses for seizures?
Pseudoseizures are a result of psychological causes such as severe mental stress, they won’t response to benzodiazepenes
What is the initial management for a seizure?
- Primary Survey
- Start a timer
- Get some help
- Wait five minutes before giving drugs as most self-terminate
What is status epilepticus?
- Medical emergency as the brain uses up all of its resources and hypoxia occurs. Can lead to sudden death months later due to effects on brain
- Can also lead to AKI due to rhabdomyolysis from muscle contractions
What is the pharmacological treatment pathway for status epilepticus?
- Wait five mins with A to E
- Benzodiazepines (Lorazepam IV)
- Benzodiazepines again
- Phenytoin Infusion
- Thiopentone/Anaesthesia but call ICU
Only take next step if not resolving
How do benzodiazepenes work in epilepsy?
GABA enhancing drug so cause cells to become hyperpolarised with Cl- ions so less likely to fire
- Lorazempam (IV): Fast acting
- Diazepam (rectally)
- Midazolam (buccal): middle acting
Put in slowly as can always add more
What investigations do clinicians do into seizures to see whether there is a diagnosis of epilepsy/which type of epilepsy a patient has?
- Ask for eyewitness accounts of seizures or videos
- EEG sleep deprived but sometimes shows no abnormalities or normal people have abnormal EEG
- MRI to rule out vascular or structual epilepsy
- FBC to check ion levels e.g Mg and Ca
Why do we give patients with epilepsy anti-epileptic drugs?
- Sudden Unexplained Death in Epilepsy risk higher in people with poor seizure control
- Massive impact on life: cannot drive, swim, have a bath, time out of work and school