Seizure And Epilepsy Flashcards
5 points of relevance for seizure and epilepsy…GO
1- Epilepsy is a common neurological condition affecting approx 1 in 200 people.
2- Epilepsy is the most common serious brain disorder worldwide with no age, racial, social class, national or geographic boundaries
3- Some of the most common maternal neurological disorders are seizures during pregnancy.
4- The frequency of seizures in pregnancy with pre existing epilepsy is known to increase by 30-50%
5- At least 50% of cases begin in childhood or adolescence.
What is tuberous sclerosis?
- A rare condition that causes growths in organs including the brain 🧠
What is Neurofibromatosis?
- A genetic condition that can cause growth on the nerves
What are 10 of the triggers and provoking factors of seizures?
1- Brain damage from prenatal or perinatal causes eg loss of O2 or trauma during birth
2- Severe head injury, haemorrhage, cerebral oedema
3- Malnutrition
4- Hyperglycaemia
5- Hyperthermia
6- Infections of the brain such as meningitis
7- Alcohol
8- Pregnancy
9- Pyrexia (temperature)
10- Parasitic disease
Explain the concept of the seizure threshold.
- This is one part of the genetic makeup
- The chance of having a seizure may depend partly on whether either or both of the parents have epilepsy
- If you have a low seizure threshold your brain is resistant to seizures, these people rate more likely to start having seizures for no obvious reason.
What are the causes and triggers for epilepsy?
- Triggers for a seizure are not the same as causes for epilepsy
- A trigger for someone to have their first seizure may be a stressful situation, but the underlying cause for that person to start having seizures may be different
- Causes can be genetic or as a result of structural damage to the brain 🧠.
Examples include:
- Not taking medication
- Sleep and epilepsy
- Photo sensitive epilepsy
- Musicogenic epilepsy
- Alcohol and drugs epilepsy
- Febrile convulsions
What are Febrile convulsions?
- This is the most common childhood neurological disease with an incidence of 1-10% in children
- However the pathophysiology of febrile convulsions remains unclear
What are some of the explanations for febrile convulsions?
- High temps may decrease the neurological threshold
- Inflammatory mediators have a role to play
- Electrolyte imbalance
What does pyrexia (high temps) do to cells?
Extremely high temps cause cellular damage by:
- Disrupting the Golgi apparatus
- Swelling of the mitochondria (this is where the conversion of glucose to ATP takes place)
- Changes cellular permeability
- Disrupts the nucleus and aggregation of chromatin which is the combination of DNA and protein in the nucleus
- Elevating protein synthesis
MEGA PRINCIPLE
What can a disruption to the sodium potassium pump cause?
- Anything that’s interferes with the sodium potassium pump can result in seizure.
- Anything that interferes with the sodium potassium pump in the heart can result in cardiac arrest.
What 5 things interfere with the sodium potassium pump?
1- O2 2- Acid 3- Cardiac output 4- Glucose 5- Change in temp
The epilepsy society divides seizures into three groups.
What are they?
- Where they start in the brain (onset)
- Whether or not a persons awareness os affected
- Whether or not seizures involve other symptoms such as memory loss
There are three classifications of seizures what are they?
1- Focal onset
2- Generalised onset
3 Unknown onset
These classifications are based on where the seizures start
What are focal onset seizures?
- these seizures start in and effect one area of the brain it might affect a large part of one hemisphere or just a small area in one of the lobes
- Sometimes they can spread to both sides of the brain ( Focal bilateral tonic- clonic seizure) this is then a warning that another seizure will happen.
What are focal aware seizures?
- In these seizures the person is conscious (aware and alert) will usually know that something is happening and will remember the seizure afterwards
- During the seizure that may feel ‘strange’ but not be able to describe the feelin afterwards.
What are focal impaired awareness seizures?
- These affect a bigger part of one hemisphere of the brain then focal onset seizures
- The persons consciousness is affected and they may be confused and difficult to communicate with
- These seizures often happen in the temporal lobes but can happen in other parts of the brain.
- After the seizure the person may be confused for a while,tired and may not remember the event at all
What are the six motor symptoms of a Focal seizure?
- Making lip smacking or shewing movements
- Repeatedly picking up objects or pulling at clothes
- Suddenly loosing muscle tone and limbs going floppy or becoming stiff
- Repetitive jerking movements that affect one or both sides of the body
- Making loud cries or screams
- Making strange postures pr repetitive movements such as cycling or kicking
What are the 5 non- motor symptoms of focal seizures?
- Deja vu
- Unusual smell or taste
- Intense feeling, fear, or joy
- Twitching, numbness, tingling
- Visual disturbances flashing lights hallucinations
What are focal to bilateral Tonic - clonic seizures?
- When this happens the person becomes unconscious and will usually have tonic clonic convulsions or shaking.
- If this happens very quickly they may not be aware that it has started as a focal seizure
What is a generalised onset seizure?
- These affect both sides of the brain at once and happen without warning
- The person will be unconscious (except in myoclonic seizure), even is just for a few seconds and afterwards will not remember what has happened during the seizure
What happens at the start of a tonic clonic seizure?
- The person becomes unconscious
- Their body goes stiff and if they are standing up they will usually fall backwards
- They may cry out
- They may bite Their tongue or cheek
What happens to a person during a tonic clonic seizure?
- They jerk and shake as their muscles relax and tighten rhythmically
- Breathing difficulties
- Incontinence
- After the seizure they may feel tired, confused or want to sleep
What are Clonic seizures?
These involve repeated rhythmical jerking movements of one side or part of the body or both sides (whole body) depending on where the seizure starts.
- Seizures can start in one side of the brain (focal) or affect both sides of the brain (generalised)
What are tonic and atonic seizures?
- In a TONIC seizure the persons muscles suddenly become stiff if stood up they often fall backwards and may injure their head. They tend to be very brief and happen without warning.
- In and ATONIC seizures the persons muscles suddenly relax and they become floppy
- With both tonic and atonic seizures people usually recover quickly apart form possible injury
What are myoclonic seizures?
Myoclonic = muscle jerk
- Muscle jerks are not always due to epilepsy (some people have them as they fall asleep)
- Myoclonic seizures are brief but can happen shortly after waking up
- In myoclonic seizures the person is conscious but they care classified as generalised seizures. This is because the person is likely to have another problem seizure such as a tonic, clonic seizure as well as a myoclonic seizure
Absence seizures
What are typical absences?
- During a typical absence the person becomes briefly blank and unresponsive for a few seconds they may appear to be daydreaming
- The person may stop what they are doing, look blank and stare. Their eyelids might blink or flutter.
- They will not respond to what is happening around them
- If they are walking they may carry on walking but not be aware of what they are doing.
Absence seizures
What are Atypical absences?
- These are similar to typical absences but they start and end slowly and last a bit longer they a typical absence.
- They also include a change in muscle tone where the limbs go limp or floppy some people may even fall.
What is the pathophysiology of seizures?
- The brains cells have to work in harmony
- The entire nervous system functions by sending nerve impulses to one another rand muscles and glands
- The electrical activity of the brain can be measured using an EEG
- In individuals with epilepsy the EEG is abnormal, characteristic wave forms are altered by the appearance of spikes in electrical activity
- The brain requires 20% of the resting cardiac output
- Most epileptic seizures are thought to be the result from abnormal hyperactive neurones that form and epileptogenic focus
- During and epileptic seizure there is abnormal and excessive discharging of impulses from brain cells.
- This reaches the Skeletal muscle fibres to stimulate contractions and later subsides due to a lack of neurotransmitters in the synapse
Why can seizures be so serious?
- During a seizure the cerebral O2 consumption increases by as much as 60%
- In status epilepticus O2 and glucose consumption by skeletal muscle contraction coupled with periods of apnoea, rapidly depletes the O2 delivery + nutritive stores leading to hypoxemia, hypercapnia and hyperglycaemia
- Seizures cause metabolic requirements to increase which results in elevation of cerebral blood flow and volume
- The increase in cellular lactate further complicate the pathophysiological state
- The end result us and energy debt that rapidly leads to cellular exhaustion
- If blood flow cannot match the demand, ischaemia develops, cerebral energy stores are depleted and irreversible neuronal destruction occurs
How can taking a history help with the diagnosis of seizures and epilepsy?
-This will help describe the seizure type, cause, duration, previous treatment and current state.
What diagnostic tests along with baseline bloods can be done to help diagnose epilepsy?
- EEG - is a measure of the cerebral function, tracing the brains electrical activity and can identify disruption
- MRI scan - uses magnetic fields and radio waves to scan the brain in a non-invasive way to identify very small lesions and scars
- CT or CAT scan- is an enhanced x-ray technique for studying the cerebral structure.
- Ambulatory EEG- the Persian wears the EEG for several days and nights recording the brains electrical activity
- Video telemetry - This consists of simultaneous EEG recording of the brains electrical activity and and a video recording of the seizures
There are 5 types of brain wave… name them…GO
1- Delta waves- deeper levels of relaxation and restorative sleep
2- Theta waves - prevalent in a trance or hypnotic state (day dreaming)
3- Alpha waves - Bridges between conscious thinking and subconscious thinking
4- Beta waves- Channelled during conscious stage such as cognitive reasoning, thinking, calculations and speaking
5- Gamma waves- involved in processing more complex tasks
