Epilepsy Flashcards
Define epilepsy
- This is a recurrent tendency to spontaneous, intermittent abnormal electrical activity, manifesting as seizures
- It is a group of many different ‘epilepsies’ with one thing in common - a tendency to have seizures that start in the brain
Define a seizure
This is abnormal discharge of electrical activity in the brain causing alterations in behaviour, sensation or convulsions
- In most brains, neuron interactions occur in a chaotic but balanced, orderly fashion with few disruptions. Occasionally small disruptions (neuron misfires) may occur with little consequence
- When multiple cells misfire at the same time, depending on the severity & location in the brain this may cause a seizure
Are all seizures due to epilepsy ?
No!
- Other conditions that can look like epilepsy include fainting, hypoglycaemia in diabetes or a change in the way the heart is working, febrile convulsions
- These are all not epileptic seizures and the cause of them does not start in the brain
- 2.5% of the population affected by seizures but ony 0.5% are affected by epilepsy
When are CT scans indicated in someone presenting with a seizure ?
- Any new seizure
- Focal seizures
- Significant post-ictal focal deficit
- Epilepsy presenting as status epilepticus
- Associated preceding persistent headache of recent onset
- Seizure frequency accelerating over weeks or months
In general when can epilepsy only be diagnosed after ?
Once they have had >1 seizure as it is a continuing tendency to have seizures
What is there a rare risk of for 1 in 1000 people with epilepsy ?
Rare risk of sudden death (SUDEP)
Do all epileptic seizures involve convulsions ?
No some people can seem vacant, wander or are confused when a seizure is occurring
Are all people aware they are going to have a seizure ?
No - some people are aware of the beginning of a seizure hrs to days before it happens. On the other hand some may not be aware of the beginning & ==> have no warning
Describe the prodome in relation to a seizure
Some patients may notice a change in mood or behaviour, this may warn a patient a seizure may come. It is not part of the seziure & not everyone gets it
Describe an aura in relation to a seizure and the type of seizure it may hint towards
- This is part of the seizure itself & may preceed the other manifestations of a seizure. The aura may be a strange feeling in the gut, deja vu, strange smells or flashing lights
- It implies a partial (focal) seizure often but not alway, from the temporal lobe
What is the ictal-phase of a seizure ?
This is the period of time from first symptoms to the end of seizure activity
Describe the post-ictal phase after a seizure
This is where there may be any of the symptoms of; headache, confusion, myalgia or a sore tongue, or temporary weakness after a focal seizure in the motor cortex or dysphagia from a seizure afecting the temporal lobe
What are the causes of epileptic seizures ?
- 2/3rds are idiopathic (often familial)
- Cortical scarring e.g. from head injury years before onset of seizures
- Structural change in the brain such as the brain not developing properly
- Damage caused by brain injury, infections such as meningitis, a stroke or a tumour
- Structural changes such as tuberous sclerosis, or neurofibromatosis (type 1), which can cause growths affecting the brain
What are the non-epileptic causes of seizures ?
- Trauma
- Stroke
- Haemorrhage
- Raised ICP
- Alcohol or benzodiazepine withdrawal
- Metabolic disturbances (increased or decreased Na+, decreased Ca2+, increased or decreased glucose etc)
- Liver disease
- Infections e.g. meningitis, syphilis, HIV
- Increased temp (febrile convulsions main one)
- Drugs e.g. tricyclics, cocaine, tramadol etc
- Pseudoseizures (non-epileptic attack disorder)
How is epilepsy diagnosed ?
1st take a detailed history from the patient & an eyewitness to the attack to determine whether or not an epiletic seizure if likely to have occurred
If diagnosis cannot be established via history then further investigations are done
