Understanding Epilepsy and Seizures

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Questions and Answers

Which of the following is NOT a common etiology for GCSE?

Diabetes Mellitus (correct)

CNS infection

Subtherapeutic anti-epileptic drug therapy

Head trauma

What is the primary mechanism of neuronal excitation in GCSE?

Inhibition of NMDA receptors

Endocytosis of sodium channels

Inhibition of GABA concentration

Unabated self-sustaining neuronal excitation (correct)

What is the effect of prolonged seizures on GABA receptors?

Enhances Na channel activation

Increases GABA receptor concentration

Increases glutamate receptor sensitivity

Leads to reduction in their inhibitory function (correct)

What does cerebrovascular disease primarily refer to?

Tumors and strokes, especially in those over 60 Signup and view all the answers

Which physiological effect is NOT driven by activation of the sympathetic nervous system during a seizure?

Decreased heart rate Signup and view all the answers

Which EEG activity is considered most useful in diagnosing epilepsy?

Activities during active seizure Signup and view all the answers

What is a potential complication of prolonged seizures related to muscle contractions?

Rhabdomyolysis Signup and view all the answers

What primarily causes neuronal hyperexcitability in epilepsy?

Alterations in Na, Ca, K, and Cl ion channels Signup and view all the answers

Which of the following is a defining characteristic of the post-ictal phase?

It involves confusion and transient neurological deficits Signup and view all the answers

Which type of seizure is characterized by intact awareness and is formerly known as a simple partial seizure?

Focal seizure with maintained awareness Signup and view all the answers

What distinguishes tonic-clonic seizures from other types?

They include a tonic phase followed by a clonic phase Signup and view all the answers

Which neurotransmitter deficiency is primarily associated with diminished inhibitory mechanisms in epilepsy?

Gamma aminobutyric acid (GABA) Signup and view all the answers

Absence seizures are primarily characterized by which feature?

Impaired consciousness without convulsions Signup and view all the answers

What is a common physiological response of the autonomic nervous system during a seizure?

Flushing and sweating Signup and view all the answers

Which term describes the sensation of unfamiliarity with familiar events or situations during a seizure?

Jamais vu Signup and view all the answers

In what type of seizure does a patient commonly experience auras that are stereotypical for them?

Complex partial seizure Signup and view all the answers

Which seizure manifestation includes non-purposeful, repetitive movements?

Automatisms Signup and view all the answers

How does the Jacksonian march typically present during a seizure?

Starts distally and progresses proximally Signup and view all the answers

What is the hallmark of generalized seizures regarding awareness?

There is impaired awareness Signup and view all the answers

Which feature is NOT typically associated with myoclonic seizures?

Loss of consciousness Signup and view all the answers

What indicates the transition from a focal seizure to a generalized seizure?

Seizure activity extends to both hemispheres Signup and view all the answers

What is the primary difference between a seizure and epilepsy?

A seizure is a single event, while epilepsy is a chronic condition of recurrent seizures. Signup and view all the answers

Which of the following is NOT a common precipitating factor for seizures?

Hypertension Signup and view all the answers

Which of the following is a common etiology of epilepsy in infants and children?

Genetic abnormalities Signup and view all the answers

What is the primary mechanism that leads to a seizure?

Simultaneous firing of cortical neurons with prolonged depolarization Signup and view all the answers

What is the role of calcium influx in the pathophysiology of a seizure?

Calcium influx is responsible for the depolarization of neurons, leading to a seizure. Signup and view all the answers

Which of the following is an example of an automatism often observed during a seizure?

Involuntary lip smacking Signup and view all the answers

What is the primary purpose of anti-epileptic medications?

To treat the symptoms of epilepsy by reducing the frequency and severity of seizures. Signup and view all the answers

Which of the following is a key characteristic of status epilepticus?

Recurring seizures without regaining consciousness between seizures. Signup and view all the answers

Which of the following is NOT a common complication of status epilepticus?

Hypoglycemia Signup and view all the answers

What is the main difference between generalized and focal seizure?

Generalized seizures affect both hemispheres of the brain, while focal seizures affect a smaller area. Signup and view all the answers

Study Notes

Epilepsy

Seizure: Abnormal electrical neuronal discharge causing motor, sensory, autonomic, or psychic changes.
Seizure ≠ Epilepsy: Epilepsy is a chronic condition of recurrent seizures.
Epilepsy etiology: Chronic underlying condition causing or predisposing to recurrent seizures.
At least two unprovoked seizures separated by 24 hours are required for a diagnosis of epilepsy.
Common precipitating factors for seizures:
- Metabolic derangements (e.g., hyponatremia, hypocalcemia, hypoglycemia, hypoxia)
- Kidney/liver failure
- Toxins/medication overdose (e.g., alcohol, heroin, benzodiazepine withdrawal)
- CNS infection (meningitis)
- Fever (in infants)

Epilepsy Pathophysiology

Normal neuronal activity: Coordinated sequential cell excitation/inhibition.
Seizure: Simultaneous firing of cortical neurons with prolonged depolarization.
- Intracellular influx of calcium and sodium.
- Stimulates more action potentials.
Imbalance: Cortical neuronal cell excitation and inhibition; hyperexcitable neurons.
Neuronal excitation spreads until inhibition mechanisms (e.g., GABA) predominate.

Epilepsy Types

Focal Seizure (formerly simple partial seizure):
- Intact awareness.
- Typically mono-hemispheric (one side of the brain).
- Peripheral manifestations are contralateral to the involved hemisphere.
- Motor involvement can "march" (start distally and progress proximally in limb).
Impaired Awareness Focal Seizure (formerly complex partial seizure)
- Impaired consciousness.
- Commonly involves the temporal lobe.
- Aura (stereotypical sensation) is common.
- May spread to both hemispheres.
- May progress to generalized tonic-clonic seizures.
- Automatisms (non-purposeful repetitive movements) are common.
Generalized Seizures:
- Typically bilateral hemispheric involvement.
- Impaired consciousness.
Absence Seizures (formerly petit mal seizures):
- Non-convulsive.
- Impaired consciousness (blank stare, "daydreaming", unresponsiveness).
- Brief duration (seconds) with return to normal activity (no post-ictal phase).
Generalized Tonic-Clonic Seizures (formerly grand mal seizures):
- Most common motor presentation.
- Sudden tonic muscle contraction.
- Extention of extremities.
- Brief interruption of breathing (cyanosis).
- Mandibular contraction (risk of biting tongue).
- Post-ictal phase (takes hours to regain consciousness, bladder/bowel incontinence is common).

Status Epilepticus

Prolonged seizure activity (≥ 30 minutes).
Generalized convulsive status epilepticus (GCSE): ~75% of cases.
Stages of GCSE: Based on duration of seizure.
Complications and mortality Risk↑ with increased duration
Common etiologies:
- Congenital/genetic conditions
- Substance withdrawal
- Head trauma
- CNS infection
- Subtherapeutic anti-epileptic drug therapy
- Sudden withdrawal of therapy
- Cerebrovascular disease (strokes, tumors).

Epilepsy Diagnostic Approach

Clinical presentation, witness history, and family history are important.
Electroencephalography (EEG) is useful during active seizure activity, but not directly helpful for diagnosis.
Additional tests (MRI, CT, lumbar puncture) can assess the underlying cause.

Medication Therapy (General)

Medications used to inhibit Na+ and Ca+ action potentials, attenuate glutamate and augment GABA.
- Examples include phenytoin, carbamazepine, lamotrigine, topiramate, benzodiazepines, barbiturates, and valproic acid.

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Description

This quiz focuses on the key aspects of epilepsy, including its definition, causes, diagnosis, and pathophysiology. Learn about the differences between a seizure and epilepsy, as well as the factors that can trigger seizures. Test your knowledge of this important neurological condition.