Seizure Disorders and Epilepsy Overview

Seizure Disorders

• Uncontrolled firing of neurons in the brain, resulting in random activity.
• Caused by either increased neuronal activation or decreased inhibition across neuronal pathways.

Epilepsy

• Characterized by recurrent seizures, often unprovoked.
• Seizures are considered unprovoked when two or more seizures happen more than 24 hours apart, with a likelihood of another seizure in the next 10 years.
• There is a familial genetic link to epilepsy.

GABA

• An inhibitory neurotransmitter that may be defective or influenced by other mechanisms.
• Defective GABA can lead to neurons depolarizing in a disorganized manner.

Causes of Seizures

• Changes in the permeability of neuronal membranes, affecting sodium and calcium channels.
• Neurotransmitter imbalance, potentially due to a defect in inhibitory neurons.
• Reduced ability of neurons to inhibit activity due to GABA deficiency.
• Enhanced excitatory activity in neurons.

Acute Seizure Causes

• Immediately following brain injury.
• Infections of the nervous system, such as meningitis.
• Electrolyte imbalances, especially hyponatremia (low sodium).
• Severe hypoglycemia, particularly after insulin administration.
• Withdrawal from drugs or alcohol.
• Brain hemorrhage or tumor.
• Toxins and medications.
• Hypoxia (lack of oxygen).

Triggers of Epileptic Seizures

• External or internal factors can trigger seizures.
• External triggers include loud noises, bright flashing lights, and biochemical stimuli like stress, medication changes, and hyperventilation (alkalosis).
• Internal triggers can include an "aura" - a sensory warning such as a smell or visual hallucination, that occurs before the seizure starts.

Characteristics of Seizure Disorders

• Seizures can last from seconds to minutes.
• People experiencing seizures may become unconscious and disoriented.
• Seizures can repeat moments later.
• Intense muscle activity may occur during seizures.
• Sensory functions may be impaired.
• Respirations may be impaired or the airway blocked.
• Repeated seizures can cause hypoxia, hypotension, acidosis, and hypoglycemia.
• Injuries can occur due to loss of consciousness during seizures.

Diagnostic and Testing

• EEG (Electroencephalogram) is used to monitor electrical activity in the brain during seizures.
• CT scans and MRI scans are used to identify structural abnormalities in the brain.
• PET (Positron Emission Tomography) scans use radioactive material to detect brain abnormalities.
• SPECT (Single-Photon Emission Computerized Tomography) scans provide a 3D map of blood flow during brain activity.

Focal Seizures

• Begin in a localized area of the brain and affect one or more parts of the body, but not the entire body.
• The individual may be conscious but unaware of the seizure.
• Simple Focal Seizures: Affect a small area of the brain, causing a twitch in an extremity or a change in sensation.
• Complex Focal Seizures: Cause muscle or nerve reactions, resulting in confusion or disorientation. Consciousness is not lost.
• Secondary Generalized Seizures: Begin as a focal seizure but spread to both sides of the brain, becoming a generalized seizure.

Generalized Seizures

• Affect both sides of the brain simultaneously, impacting the entire body.
• The person experiences loss of consciousness and remains unaware until the seizure ends.
• A post-ictal period of confusion follows the seizure.
• Absence Seizures: Also known as petit mal seizures, they can go unnoticed. The person may stare blankly and become unresponsive for a brief period. There is loss of consciousness, but not always atonia (muscle slackness). No significant muscle activity is observed.
• Tonic-Clonic Seizures: Characterized by sudden tightening and loosening of all major muscle groups, also known as grand mal seizures or convulsions. Loss of consciousness and potential injury result. All extremities become rigid.

Response to Seizures

• Protect and support the person's airway and breathing.
• Prevent injury.
• Start timing the seizure and stay with the person.

Treatment

Acute Symptomatic Seizures

• Address the underlying cause.
• Correct electrolyte imbalances like hyponatremia (low sodium) or hypoglycemia (low blood sugar).
• Administer anti-seizure medications or benzodiazepines.
• Status epilepticus: Refers to seizures that last for an extended period of time and require emergency care.

Chronic Epilepsy Management

• Identify and avoid triggers that increase the risk of seizures.
• Take anti-seizure medications daily.
• Driving may be restricted.

Aspects of Seizure Disorders

• Environmental factors: Toxins and chemical ingestion.
• Lifestyle factors: Drug and alcohol use, brain injury.
• Genetics and congenital birth defects.
• Age: Older adults may experience more severe complications.

Seizure Prevention

• Manage diabetes and insulin carefully.
• Avoid medication triggers.
• Wear protective equipment when engaging in activities that carry a risk of head injury.
• Understand and avoid individual seizure triggers.

This quiz covers key concepts related to seizure disorders, including the nature and causes of epilepsy. It explores the role of neurotransmitters, particularly GABA, in the occurrence of seizures. Additionally, the quiz discusses the genetic factors and various mechanisms that contribute to seizure activity in the brain.