WEEK 3: Epilepsy Flashcards
What is a seizure?
Seizures are sudden, transitory, and uncontrolled episodes of brain dysfunction resulting from abnormal discharge of neuronal cells with associated motor, sensory or behavioral changes.
Seizures result from paroxysmal and excessive electrical neuronal discharges in the brain that cause a variety of clinical manifestation.
While The term EPILEPSY is usually restricted to those cases with a tendency for recurrent seizures.
What is epilepsy?
Epilepsy is a group of chronic CNS disorders characterized by recurrent seizures.
Discuss epilepsy prevalence.
There are 2 million Americans with epilepsy in the US alone
(CDC- Center for Disease Control and Prevention, 2011)
WHO estimates that 10 million people in Africa live with
Epilepsy (80% NOT treated) *
In 2004, WHO estimated the lifetime prevalence rate for active epilepsy **
1.5- 14 per 1000 person-years in ASIA
5.1- 57 per 1000 person-years in Latin America
5.2 to 74.4 per 1000 person-years in Sub-Saharan Africa
Highest in the very young and the elderly
Almost 10% of the population will experience at least one epileptic seizure in 80 years of life.
What is Botswana’s ranking of epilepsy in the world?
Epilepsy as a CAUSE of DEATH in Botswana – #16 worldwide in 2017
Describe the mechanism of seizure generation.
Excitation (too much)
Ionic—inward Na+, Ca++ currents
Neurotransmitter—glutamate
Inhibition (too little)
Ionic—inward CI-, outward K+ currents
Neurotransmitter—GABA
Discuss the importance of a GOOD history.
The first goal is to determine whether the event was truly a seizure.
Questions should focus on the symptoms before, during, and after the episode in order to differentiate a seizure from other paroxysmal events.
Seizures frequently occur out-of-hospital, and the patient may be unaware of the ictal and immediate post-ictal phases; thus, witnesses to the event should be interviewed carefully.
Discuss psychogenic seizure.
Describe the presentation of psychogenic seizures.
Psychogenic seizures, also known as non-epileptic seizures (NES) or psychogenic non-epileptic seizures (PNES), are episodes that resemble epileptic seizures but are not caused by abnormal electrical activity in the brain.
Instead, they are thought to be triggered by psychological factors such as stress, trauma, or emotional distress.
These seizures can be challenging to diagnose and manage because they mimic epileptic seizures in appearance but have different underlying causes.
Head shaking side to side, abdominal thrusting, bicycling, crying, tremors/shaking of the face… suspect Psychogenic Seizures
Describe the Classification of Epilepsy.
I. Partial (focal) Seizures
Simple Partial Seizures
Complex Partial Seizures
Partial Seizures with secondary generalization
II. Generalized Seizures
Generalized Tonic-Clonic Seizures
Absence Seizures
Tonic Seizures
Atonic Seizures
Clonic and Myoclonic Seizures
III. Unclassified Seizures
Includes all seizures that defy classification due to incomplete data… An example is seizures in infancy, which may involve chewing, swimming movements, eye movements apnea and have NOT yet subtyped…
Discuss partial seizures.
Describe the 3 types of partial seizures.
Partial (focal) seizures are a type of seizure that originates in a specific area of the brain, rather than involving the entire brain.
They are characterized by abnormal electrical activity in a localized region, which can result in a wide range of symptoms depending on the area of the brain affected.
Begin focally in a restricted area of the cortex.
The symptoms could be simple (motor or sensory phenomenon) or complex (automatisms and/or unawareness)
Partial seizures can spread to other areas and evolve into generalized tonic-clonic seizure.
- Simple Partial Seizures
Jacksonian
*Begin focally in a restricted area of the cortex
*No alteration of consciousness
*EEG: Excessive synchronized discharge by a small group of neurons. Contralateral discharge
They can result in abnormal sensations, movements, or feelings that are localized to one part of the body or one side of the body.
Examples of symptoms include tingling, twitching, dizziness, visual disturbances, or unusual smells or tastes.
- Complex Partial Seizures
*Temporal Lobe Epilepsy or Psychomotor Seizures
*Produces confusion or dazed behavior, stares into space
*Automatism – grimacing, gesturing, lip smacking
*Consciousness impaired
*EEG: Bizarre generalized EEG activity with evidence of temporal lobe focal abnormalities
*Memory loss for events occurring during the seizure - Partial Seizures with secondary generalization
In some cases, partial seizures may begin in a localized area of the brain but then spread to involve both hemispheres, leading to a generalized seizure.
This progression is referred to as secondary generalization and can result in a loss of consciousness and widespread motor activity characteristic of generalized seizures.
Discuss generalized seizures.
Begin with bilateral hemisphere involvement from the onset of the seizure.
There will be immediate impairment of consciousness with no noted focal onset.
May manifest with absences, tonic clonic seizures, myoclonic jerks or atonic attacks.
Discuss the 5 types of generalized seizures.
- Generalized Tonic-Clonic Seizures
Formerly known as grand mal seizures, these are the most dramatic and well-known type of seizure. They typically involve two phases:
*Tonic phase: The muscles suddenly contract, causing stiffness and rigidity throughout the body. This phase often lasts for a few seconds to a minute. Sustained powerful muscle contraction which arrests ventilation.
*Clonic phase: This is characterized by rhythmic, jerking movements of the limbs and body. The person may also experience loss of bladder or bowel control and may bite their tongue or cheek. This phase can last for a couple of minutes.
After the seizure, the individual may experience confusion, fatigue, or headache.
- Absence Seizures
Formerly called petit mal seizures, these seizures are characterized by a brief loss of consciousness and absence of motor activity.
Usually of short duration (5-10 sec), but may occur several times in a day
The person may appear to stare blankly into space for a few seconds, with a sudden return to awareness afterward.
Absence seizures often occur in children and may be mistaken for daydreaming or inattention.
- Tonic Seizures
Tonic seizures involve sudden and prolonged muscle contractions, leading to stiffening of the muscles.
They typically affect the muscles of the back, arms, and legs, causing the person to fall if they are standing.
Tonic seizures usually last less than 20 seconds and may be followed by a period of confusion or drowsiness.
- Atonic Seizures
Also known as drop attacks or akinetic seizures, atonic seizures involve a sudden loss of muscle tone, causing the person to collapse or fall to the ground.
These seizures can occur without warning and may result in injuries if the person falls.
Atonic seizures are relatively brief and are followed by a rapid recovery of consciousness.
- Clonic and Myoclonic Seizures
Clonic seizures are characterized by repetitive, rhythmic jerking movements of the muscles.
Myoclonic seizures involve sudden, brief muscle jerks or twitches that may affect one part of the body or the entire body.
Both types of seizures typically last for a few seconds to a minute and may occur in clusters.
Discuss investigations for seizures.
- EEG – the awake EEG is often normal
Hyperventilation, photic stimulation, and sleep-deprived EEG can increase the likelihood of finding an abnormality in EEG.
A normal EEG does not rule out the diagnosis of Epilepsy.
- Video EEG – continuous video and synchronized EEG recording usually for 24 hours or more.
*Useful in the diagnosis of patients with non-epileptiform events such as psychogenic seizures.
*Also useful in patients with frequent and several episodes in a day.
- Neuroimaging
Useful in:
*Focal seizures
*Seizures suspected to be symptomatic in origin
*Difficult to control seizures (MRI- sz protocol)
CT scan should be the initial investigation in epileptic patients.
MRI may be performed taking into consideration patient’s socioeconomic status and the type of epilepsy.
LAB TYESTS
*FBC, Checkj electrolyte balances
Describe the treatment of seizures.
The aim of treatment is to control seizures with the most appropriate antiepileptic drug (AED) without causing any significant side effects.
Treatment of epilepsy with AED should be started after confirming the diagnosis of epilepsy.
Initiated following two or more unprovoked seizures.
Conventional or First-Line Drugs:
- Phenytoin:
Mechanism of Action: Phenytoin primarily acts by blocking voltage-gated sodium channels in neurons, which reduces the excessive neuronal firing responsible for seizures. It stabilizes the neuronal membrane and limits the spread of abnormal electrical activity. - Phenobarbital:
Mechanism of Action: Phenobarbital is a barbiturate that enhances the activity of the neurotransmitter gamma-aminobutyric acid (GABA) by increasing the duration of GABA-mediated chloride channel opening. This leads to neuronal inhibition, reducing excitability and preventing seizure activity. - Carbamazepine:
Mechanism of Action: Carbamazepine primarily acts by blocking voltage-gated sodium channels, similar to phenytoin. By inhibiting sodium influx into neurons, carbamazepine stabilizes neuronal membranes and decreases abnormal electrical activity. - Oxcarbazepine:
Mechanism of Action: Oxcarbazepine is structurally related to carbamazepine and exerts its antiepileptic effects through similar mechanisms. It blocks voltage-gated sodium channels, stabilizing neuronal membranes and reducing the likelihood of seizures. - Valproate:
Mechanism of Action: Valproate has multiple mechanisms of action, including enhancing GABAergic neurotransmission by increasing GABA levels and inhibiting the breakdown of GABA. It also modulates voltage-gated sodium channels and calcium channels, reducing neuronal excitability and preventing seizure propagation.
New or Second-Line Drugs:
- Lamotrigine:
Mechanism of Action: Lamotrigine primarily inhibits voltage-gated sodium channels, similar to phenytoin and carbamazepine. By reducing sodium influx into neurons, lamotrigine stabilizes neuronal membranes and inhibits the release of excitatory neurotransmitters, thereby preventing seizure activity. - Levetiracetam:
Mechanism of Action: Levetiracetam’s precise mechanism of action is not fully understood, but it is believed to involve binding to synaptic vesicle protein 2A (SV2A), which modulates neurotransmitter release. By reducing neurotransmitter release, levetiracetam dampens excessive neuronal excitability and prevents seizures. - Topiramate:
Mechanism of Action: Topiramate acts on multiple targets, including voltage-gated sodium channels, GABA receptors, and glutamate receptors. It enhances GABAergic neurotransmission, inhibits excitatory glutamatergic transmission, and modulates sodium channels, collectively reducing neuronal excitability and preventing seizures.
Discuss the 5 treatment goals for seizures.
- No Seizures:
The ultimate treatment goal for individuals with epilepsy is to achieve seizure freedom or significant reduction in seizure frequency.
This not only improves the individual’s quality of life but also reduces the risk of injury and other complications associated with seizures.
- No Side Effects:
While controlling seizures is essential, it’s equally important to minimize the side effects of anti-epileptic medications.
Side effects can significantly impact an individual’s quality of life and may lead to medication non-adherence or discontinuation.
- Monotherapy:
Monotherapy, or the use of a single anti-epileptic medication, is preferred whenever possible, as it reduces the risk of drug interactions and simplifies the treatment regimen. - Once Daily Dosing:
Once-daily dosing schedules are preferred as they improve medication adherence and convenience for individuals with epilepsy. This reduces the likelihood of missed doses and helps maintain consistent drug levels in the bloodstream, optimizing seizure control. - No Blood Tests:
Minimizing the need for frequent blood tests is desirable to reduce inconvenience and discomfort for individuals with epilepsy.
What actually happens in SEIZURE TREATMENT?
70 % - seizure freedom with one drug
5-10% - seizure freedom with two or more drugs
20% - will still have seizures
