32 Questions
What percentage of patients with epilepsy have seizures completely controlled by optimal drug therapy?
75%
Which of the following mechanisms is NOT a way that antiepileptic drugs prevent proximal discharge?
Correct underlying neuronal abnormality
What is the primary mechanism of action of vigabatrin?
Inhibits GABA transaminase
Which type of calcium channel is inhibited by ethosuximide?
T-type Ca2+ channel
What is the primary mechanism of action of gabapentin?
Binds to the α2δ1 subunit of P/Q-type Ca2+ channels
What is the estimated percentage of epilepsy cases that involve genetic mutations?
1/3
What is the mechanism of action of Levetiracetam in terms of synaptic transmission?
Binds synaptic vesicle protein 2A (SV2A) and interferes with NT release
Which antiepileptic drug is known for its multiple mechanisms of action?
Topiramate
What is the primary problem with NMDA antagonists as antiepileptic drugs?
Too narrow therapeutic window
What is the effect of inhibiting T-type Ca2+ channels in terms of seizure type?
Effective in absence seizures
What are the three major categories of antiepileptic drugs?
Enhance GABA action, Inhibit Na+ channels, Inhibit Ca2+ channels
What percentage of the population is affected by epilepsy?
0.5-1%
Which type of seizure is characterized by abrupt stopping of activity, staring vacantly for a few seconds, and abrupt recovery with no after effects?
Absence seizure
What is the main purpose of Electroencephalography (EEG)?
To detect electrical activity in the brain
What is the name of the type of epilepsy that is associated with progressive mental retardation and excitotoxic neurodegeneration?
Lennox-Gastaut syndrome
Which of the following is NOT a type of brain imaging?
Computed Tomography (CT)
What is the term for the initial strong contraction of whole musculature that occurs during a tonic-clonic seizure?
Tonic phase
Kainic acid injection in the amygdaloidal nucleus of a rat results in spontaneous seizures within 24 hours.
False
Electrically induced seizures can be prevented by GABA antagonists.
False
Valproate is primarily used to treat absence seizures due to its ability to block T-type Ca2+ channels.
False
Tiagabine is used to treat partial seizures by inhibiting GABA transaminase.
False
Carbamazepine is effective in treating all types of seizures, including absence seizures.
False
Levetiracetam binds to voltage-gated Na+ channels
False
Topiramate is a specific inhibitor of T-type Ca2+ channels
False
NMDA antagonists have a wide therapeutic window
False
Ethosuximide is an inhibitor of voltage-gated Na+ channels
False
All antiepileptic drugs act by enhancing GABA action
False
Antiepileptic drugs work by enhancing the action of Na+ channels.
False
Generalised seizures always begin with a local discharge before spreading to other parts of the brain.
False
Magnetic Resonance Imaging (MRI) is used to detect electrical activity in the brain.
False
Psychomotor seizures are characterized by involuntary jerking of a muscle group.
False
Lennox-Gastaut syndrome is a type of partial seizure disorder.
False
Study Notes
Overview of Epilepsy
- Epilepsy is a common disorder characterized by seizures, which affect 0.5-1% of the population
- Often, there is no recognizable cause, but it can be caused by brain damage, inherited neurological syndromes, trauma, stroke, infection, or tumour
- Epilepsy is a neurological disorder that exhibits periodic seizures, which are episodic high-frequency discharges of impulses by a group of neurons (focus)
Imaging
- Electroencephalography (EEG) detects electrical activity, recording from electrodes, and recognizes the type of seizure by nature and distribution of the abnormal discharge
- Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) are also used for imaging
Types of Epilepsy
- Partial seizures:
- Jacksonian epilepsy: Focus in motor cortex, repetitive involuntary jerking of a muscle group, begins one side of body, and spreads
- Psychomotor epilepsy: Consists of purposed movements, lasts a few minutes, and patient recovers with no recollection
- Generalised seizures:
- Tonic-clonic: Two phases, initial strong contraction of whole musculature (tonic phase), and series of violent, synchronous jerks (clonic phase)
- Absence seizure: Abruptly stops activity, stares vacantly for a few seconds, and recovers abruptly with no after effects
- Lennox-Gastaut: Severe, associated with progressive mental retardation, due to excitotoxic neurodegeneration
Antiepileptic Drugs
- Mechanism of action:
- Enhance GABA action
- Inhibit Na+ channels
- Inhibit Ca2+ channels
- Examples:
- Benzodiazepines: Enhance activation of GABAA, used for acute seizures in children and status epilepticus
- Vigabatrin: Irreversibly inhibits GABA transaminase (GABA-T), used for all types of epilepsy
- Carbamazepine: Voltage-gated Na+ channel blockers, used for all types of epilepsy except absence seizures
- Ethosuximide: T-type Ca2+ channel inhibition, used for absence seizures
- Galapentin: P/Q-type Ca2+ channel inhibition, used for partial seizures
- Valproate: Used for all types of epilepsy, especially effective in infantile epilepsy
- Levetiracetam: Binds synaptic vesicle protein 2A (SV2A), interferes with NT release, used for partial seizures
- Topiramate: Blocks Na+ and Ca2+ channels, enhances GABA action, and blocks AMPA, used for partial and generalised seizures
This quiz covers the basics of epilepsy, including its causes and effects on the brain. It also delves into the different types of antiepileptic drugs and how they work to reduce seizures. Test your knowledge on this important neurological disorder.
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