Neuroscience of Seizures and Treatment

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Questions and Answers

Which local anesthetic has a slow onset and long duration with a great potential for toxicity?

Mepivacaine

Lidocaine

Bupivacaine

Tetracaine (correct)

Which anesthetic is specifically indicated for patients with hypertension?

Bupivacaine

Etomidate (correct)

Proprofonol

Ropivacaine

What is the primary action of amphetamines in treating ADHD?

Block reuptake of serotonin

Block reuptake of NE and dopamine (correct)

Promote reuptake of dopamine and norepinephrine

Increase reuptake of NE only

Which drug is a prodrug of amphetamine used to treat ADHD and obesity?

Lisdexamfetamine Signup and view all the answers

What is a common CNS adverse effect associated with CNS stimulants?

Dizziness Signup and view all the answers

What mechanism of action does modafinil utilize?

Atypical transporter mechanism Signup and view all the answers

Which local anesthetic is contraindicated in pregnant women due to its toxicity to neonates?

Mepivacaine Signup and view all the answers

What is the treatment for malignant hyperthermia?

Dantrolene Signup and view all the answers

Which substance is responsible for xerostomia as a side effect of CNS stimulants?

Vasoconstriction Signup and view all the answers

Which of the following CNS stimulants is the first non-stimulant treatment for ADHD?

Atomoxetine Signup and view all the answers

What is the primary mechanism of action for Phenytoin?

Voltage gated Na+ channel inhibitor Signup and view all the answers

Which of the following seizure types is associated with a loss of awareness?

Absence seizure Signup and view all the answers

What is a common adverse effect of Carbamazepine?

Hyponatremia Signup and view all the answers

What type of seizures is Ethosuximide primarily used to treat?

Absence seizures Signup and view all the answers

Which drug is known for having a mechanism of action that is not fully understood?

Levetiracetam Signup and view all the answers

Which antiepileptic drug is most likely to cause Steven Johnson syndrome?

Lamotrigine Signup and view all the answers

What is an effect of Benzodiazepines when used in managing seizures?

Sedation Signup and view all the answers

What is the expected outcome of antiepileptic therapies?

Control and reduce frequency Signup and view all the answers

What is the main therapeutic use of Valproic acid?

Generalized seizures Signup and view all the answers

Gabapentin resembles other AEDs but has a unique aspect; what is it?

Has no relation to GABA Signup and view all the answers

What type of seizures involve rapid loss of muscle tone?

Atonic seizures Signup and view all the answers

Which neurotransmitter is primarily affected by the action of Benzodiazepines?

GABA Signup and view all the answers

What phenomenon occurs when there is irregular electrical activity in the brain during a seizure?

Localized firing Signup and view all the answers

Which local anesthetic is known to have a vasodilating effect?

Procaine Signup and view all the answers

Study Notes

Action Potentials and Seizures

Sodium (Na+) channels are crucial for action potentials. Slowing Na+ channels slows action potential transmission and can suppress seizures.
Calcium (Ca+) channels are implicated in absence seizures. Blocking Ca+ channels in the hypothalamus can prevent these seizures.

Antiepileptic Drugs (AEDs)

AEDs can have adverse effects, including increased suicidal thoughts, fetal abnormalities, and dermatological reactions like rashes and Stevens-Johnson syndrome.

Types of Seizures

Focal onset seizures stay confined to one hemisphere of the brain. Impaired awareness can occur, but isn't always present.
Generalized onset seizures are more problematic as they originate in core brain areas (thalamus or brainstem) and spread.
Absence seizures are characterized by brief lapses of awareness (seconds) without loss of posture. They are common in childhood, typically resolving by adulthood.
Tonic-clonic seizures involve muscle stiffness and rhythmic jerking.
Atonic seizures involve rapid loss of muscle tone.
Myoclonic seizures involve sudden, brief muscle contractions.

Seizure Characteristics

Seizures are not typically life-threatening.
The brain usually stops a seizure.
Breathing may stop for seconds during a seizure.
Patients do not feel pain during seizures.
Post-seizure effects can include altered behavior.
Seizures involve irregular electrical activity in the brain.
Localized seizures involve high-rate firing in one hemisphere.
Generalized seizures involve irregular firing throughout the brain.

Seizure Treatment

Treatment aims to identify and address the cause and control seizures.
AEDs suppress seizure frequency, not cure them.
Therapy supports seizure management and prevention.

Specific AEDs and Mechanisms of Action

Phenytoin: Na+ channel inhibitor, slows repetitive firing, treats tonic-clonic and focal onset seizures. Adverse effects include gingival hyperplasia and drug metabolism interaction.
Carbamazepine: Na+ channel inhibitor, slows neuron firing; treats focal, focal bilateral, and tonic-clonic seizures. Adverse effects include hyponatremia, dermatological toxicity (Stevens-Johnson syndrome), and drug interactions.
Oxcarbazepine: Similar to carbamazepine, primarily for focal seizures, has a slightly reduced risk of drug interactions. Adverse effect risk increased for hyponatremia.
Lamotrigine: Na+ channel inhibitor, effective for focal, generalized, and tonic-clonic seizures. Adverse effects include suicidal ideation and Stevens-Johnson syndrome.
Levetiracetam: Mechanism unknown, used for various seizure types (focal, tonic-clonic, generalized, and myoclonic). Adverse effects include mood and behavior changes.
Valproic acid: Na+ and Ca+ channel blocker, GABA synthesis stimulant; treats generalized, tonic-clonic, and myoclonic seizures. Potential adverse effects include toxicity, hepatotoxicity, pancreatitis, and potential pregnancy and drug interaction concerns.
Ethosuximide: Ca+ channel inhibitor; first-line treatment for absence seizures. Relatively well-tolerated.
Gabapentin: Ca+ and K+ channel blocker; used for focal and tonic seizures, neuropathic pain, and migraine.
Pregabalin: Similar to Gabapentin, potentially greater adverse effect risk. (weight gain, xerostomia)

Benzodiazepines

Positive allosteric modulators of GABA receptors and can be used in status epilepticus.
Adverse effects include sedation, anesthesia, lethargy, behavioral changes, GI upset, and increased risk of status epilepticus during sudden withdrawal.
Includes PAMs for status epilepticus management.

Local Anesthetics

Classified as amino esters and amino amides based on their chemical structure and metabolism in the body.
Local anesthetics work by blocking pain perception, have high affinity for areas with high pain stimuli.
Important factors include water solubility for injection, becoming lipophilic for membrane crossing, and the need for vasoconstriction (often with epinephrine) to limit systemic absorption.
Some specific examples include: Cocaine, Procaine, Chloroprocaine, Benzocaine, Tetracaine, Lidocaine, Mepivacaine, Bupivacaine, Ropivacaine.
Their use is directly related to the desired outcome in terms of onset, duration, systemic toxicity and the route of administration. pH can also play a role in drug concentration.

Other CNS Stimulants

Malignant Hyperthermia: Characterized by a dangerously high body temperature. Treatment includes dantrolene.
Proprofol, Etomidate: General anesthetics with different properties; Propophol is a GABA receptor modulator (increasing sensitivity), while etomidate is selected for use in hypertensive patients.
Methylxanthines (caffeine, chocolate, tea): Block phosphodiesterase (increasing cAMP), block adenosine; used to treat airflow obstruction, bradycardia, and acute cardiac decompensation.
Amphetamines, Lisdexamfetamine, Methamphetamine, Methylphenidate (Ritalin), Atomoxetine: Used to treat ADHD, narcolepsy, and obesity. Amphetamines are reuptake blockers of NE and dopamine.
Ephedrine: Mixed-acting monoamine release; stimulates presynaptic NE release, used in anesthesia-induced hypertension, cardiogenic shock, and nasal congestion.
Modafinil: With an unknown mechanism, used to treat narcolepsy and sleep apnea.

CNS Stimulant Dependence

CNS stimulant dependence includes extensive psychological dependence and is a scheduled drug.
Physical withdrawal is often mild.

CNS Stimulant Adverse Effects

Common adverse effects include headaches, dizziness, tremors, irritability, insomnia, and appetite suppression.
These can lead to weight loss, stunted growth in children/adolescents, and xerostomia (dry mouth), which can increase risk of tooth decay.
Cardiovascular effects include palpitations, chills, and potential arrhythmias, chest pain, and increased HR/BP at high doses.
Drug holidays can help with adverse effects regarding appetite.

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Description

This quiz explores the mechanisms of action potentials and the role of antiepileptic drugs (AEDs) in managing seizures. It also covers different types of seizures, including focal, generalized, absence, and tonic-clonic seizures. Dive into the critical aspects of neurological function and therapeutic interventions.