Epilepsy and Seizures Flashcards
What is a seizure? What can they be caused by?
A seizure is a transient occurrence of signs or symptoms due to abnormal, unsynchronized neuronal activity in the brain. It is a sudden clinical event, that occurs with a clear beginning and end.
They can occur at any age, have variable recurrence and can have multiple etiologies.
A seizure can be a manifestation of CNS injury : CNS disorder (vascular disorders, head injuries, hypoxia), metabolic disorder (hypo/hyperglycemia, hypo/hypernatremia), toxic disorder (alcohol withdrawal syndrome, cocaine), infectious diseases.
A previous seizure increases the chances of having another one, especially if the cause remains : missed medication intake, altered drug absorption, pharmacokinetic interactions, sleep deprivation, alcohol intake.
Semiology of seizures?
Semiology of seizure focuses on how different parts of the brain contribute to specific signs and symptoms during a seizure. This can help identify the epileptogenic zone.
- It is important to recall initial symptoms and details as they can provide important clues to the epileptogenic zone.
- Patterns of seizure spread often start with face jerks and the progress to the upper and then lower limbs.
- Lobe specific seizure.
- The temporal lobe generates cognitive and emotional symptoms such as Deja vu, can cause auditory or olfactory hallucinations and is associated to automatisms such as lip smacking, chewing.
- The occipital lobe may cause visual hallucinations that vary in complexity.
International classification of siezures 1981 and the new ILAE classification of 2017?
The international classification of seizures 1981 is old but still used.
- Partial seizures that can be :
- Simple (no loss of consciousness) and can be sensory, motor, psychic, autonomic.
- Complex (with impaired consciousness) and can be with/without aura and with/without automatisms.
- Generalized seizure (wide area of brain) and can be tonic-clonic, atonic, myoclonic.
The new ILAE classification isn’t based on :
- Onset :
- Focal, starts from specific point in the cortex.
- Generalized, both hemispheres affected since beginning.
- Unknown.
- Motor involvement.
- Awareness.
What is an absence seizure?
Absence Seizure is a type of generalized seizure most commonly seen in children, though it can occasionally occur in young adults. It’s essential to differentiate it from “minor seizures” because, in absence seizures, there are no jerks or tonic-clonic movements.
Pathophysiology: Thought to be due to abnormal interactions between the cortex and the thalamus, leading to sudden, synchronized discharges across the brain.
Clinical Presentation : the child suddenly stops an activity (like reading or drawing), becomes unresponsive, and exhibits a “blank stare” or behavioral arrest. There may be some minor movements such as slight blinking or muscle twitching. Unlike other generalized seizures, the patient recovers immediately.
What is epilepsy?
Epilepsy is a brain disorder characterized by a long-term predisposition to generate epileptic seizures. Historically, the diagnosis of epilepsy required at least two unprovoked seizures occurring more than 24 hours apart. This definition arose from the observation that the risk of a second seizure following a single event was about 30%, but it rose to around 70% after a second event, indicating a stronger likelihood of recurrent seizures.
The modern approach to epilepsy diagnosis doesn’t always require two seizures. A single seizure can be enough for diagnosis if risk factors indicate a high likelihood of recurrence, equivalent to the risk seen after two unprovoked seizures. Risk factors include imaging abnormalities, epileptiform discharges on EEG, nocturnal seizures. Also depends on the lifestyle and occupation.
Classification of epilepsy?
Seizure classification is based on the onset of the seizure, which refers to the initial area of the brain where abnormal activity begins, rather than how the seizure evolves over time.
- Focal seizures —> activity spreads from a specific locus.
- Generalized forms of—> sudden involvement of all the cortex.
- Combined forms —> generally associated with encephalopathies.
- Unknown.
What are the main causes of epilepsy, and how is understanding its etiology important for treatment?
Epilepsy can have various causes:
- generalized epilepsies are often genetic, linked to polygenic familiarity, with abnormal thalamus-cortex interactions leading to widespread cortical involvement.
- Combined epilepsies are secondary to conditions like developmental delays or encephalopathies. Emerging evidence highlights immunological (autoimmune-related) and metabolic factors as additional causes.
Understanding etiology is essential for assessing recurrence risks and disease progression, but current treatments (anti-seizure medications) address symptoms, not the root causes, making research into these mechanisms critical for future therapies.
What is epileptic syndrome? How are they distinguished?
It is a specific set of seizure types and EEG with imaging that tends to have age dependent features, triggers and prognosis.
Until 2022 they were distinguished binary : self limited, syndromes with a spontaneous resolution and often age related and pharmacoresistant/catastrophic, do not show spontaneous resolution.
Later ILAE published many papers regarding the classification. What is impirnat to understand is that these syndromes are a spectrum. So as a patient ages they can move across this spectrum from a benign phenotype to a malignant one. This is because epilepsy is polygenic.
West syndrome?
West Syndrome, with an incidence of 2-4 per 1,000 births, is characterized by epileptic spasms (brief flexion or extension movements lasting 1-3 seconds, primarily of the head and upper limbs) and an EEG pattern of hypsarrhythmia. Diagnosis is typically based on psychomotor regression. The syndrome can be symptomatic or not, depending on its etiology. Prognosis is often poor, with most patients developing intellectual disabilities. While spasms usually resolve by ages 3-5, many cases progress to Lennox-Gastaut Syndrome. Despite its varied etiologies, West Syndrome is classified as a single entity due to shared diagnostic criteria and treatment responses.
Lennox Gastaut?
Lennox-Gastaut Syndrome (LGS) is an epileptic and developmental encephalopathy characterized by a diagnostic triad: multiple seizure types (notably tonic-clonic seizures and status epilepticus), intellectual impairment, and distinctive EEG findings. The prognosis is poor, with most patients experiencing intellectual disabilities and refractory seizures persisting into adulthood.
Dravet Syndrome?
Dravet Syndrome (DS) is an epileptic encephalopathy that begins within the first year of life and is marked by normal development prior to the onset of seizures. The first epileptic episode often coincides with high fever, leading to misattribution to vaccinations. It is commonly linked to mutations in the SCN1A gene affecting Na+ channels, though this mutation alone does not cause the condition. After one year, patients experience various seizure types, including myoclonic, generalized, focal, and absence seizures. DS causes cognitive decline due to both the disease and recurrent seizures. Treatment is challenging, but the recently developed drug fenfluramine has shown promise in reducing seizure frequency and improving non-seizure outcomes, such as executive function.
Panayiotopoulus syndrome?
Panayiotopoulos Syndrome is a benign childhood epilepsy typically affecting children aged 3-6 years. Its hallmark symptom is nocturnal episodes of confusion and prolonged vomiting, often misdiagnosed until a final convulsion occurs. Diagnosis is confirmed with an EEG, especially during sleep, as excessive epileptic discharges can disrupt sleep architecture, crucial for development. Treatment is only necessary if EEG findings indicate significant sleep disruption.
Childhood absence epilepsy?
Childhood Absence Epilepsy (CAE) is a common type of generalized genetic epilepsy affecting children and young adults. It is characterized by absence seizures, brief episodes lasting 3-10 seconds, often triggered by hyperventilation. These seizures can be self-triggered by children as they may perceive them as pleasurable. The EEG typically shows generalized 3 Hz spike-and-wave discharges. Prognosis is generally good, but in some cases, CAE can progress to other genetic epilepsies.
Janz Syndrome?
Juvenile Myoclonic Epilepsy (Janz Syndrome) is a common epilepsy characterized by myoclonic seizures and generalized seizures, with absence seizures being rare. It typically begins during puberty or later, often presenting with generalized myoclonic seizures. Sleep deprivation is a major trigger for seizures in this condition, making lifestyle management crucial. Early diagnosis is important, as some medications can worsen the condition. Fortunately, Janz Syndrome is highly drug-sensitive, and most patients achieve seizure freedom with low-dose therapy, though it is a lifelong condition that rarely resolves spontaneously.
Rolandic epilepsy?
Rolandic Epilepsy is one of the most common childhood epilepsies. It typically involves nocturnal focal motor seizures without impaired consciousness. Prognosis is generally good, and treatment is often unnecessary unless seizures are frequent. Sleep EEG is crucial to rule out continuous spike-and-wave during sleep (CSWS), which can cause cognitive impairments, particularly in speech and comprehension. Neuropsychological evaluation is recommended to detect cognitive regression and guide treatment decisions if needed.
Landau Kleffner syndrome?
Landau-Kleffner Syndrome is a form of epilepsy characterized by a specific impairment in speech and comprehension. Patients often experience cognitive regression, which requires evaluation by a neuropsychologist. If cognitive decline is detected, treatment is indicated to address the neurological and developmental concerns associated with the syndrome.
Lafora disease and Unverricht-Lundborg disease?
Lafora Disease and Unverricht-Lundborg Disease are rare, progressive myoclonic epilepsies that typically begin with myoclonic and generalized myoclonic seizures, similar to juvenile myoclonic epilepsy. However, they evolve into progressive forms, leading to both motor and cognitive deterioration. These conditions are often genetically inherited, with onset usually occurring between childhood and adolescence. The main characteristics include cortical myoclonic seizures and progressive cognitive impairment.
What is Status Epilepticus, and why is it a medical emergency?
Status Epilepticus (SE) is defined by recurrent (2 or more in 30 min) seizures without recovery between episodes, seizures lasting longer than 5 minutes, or non-convulsive seizures exceeding 20 minutes. It is a medical emergency because prolonged seizures can cause neuronal death, brain network damage, and increase the risk of developing epilepsy. SE is categorized by two critical time points:
• T1: The time (e.g., 5 minutes for tonic-clonic SE) after which a seizure is unlikely to stop spontaneously, requiring urgent intervention.
• T2: The maximum time (e.g., 30 minutes for tonic-clonic SE) before which the seizure state must be resolved to prevent critical complications.
Tonic-clonic SE progresses from an initial compensatory phase (increased CO2, blood pressure, blood sugar, and lactate) to a decompensation phase, leading to respiratory collapse, rhabdomyolysis, kidney failure, and multi-organ failure if untreated. Immediate medical intervention is essential.
