Summary of the Class on Epilepsy
In this lecture, we discussed the neurological disorder known as epilepsy, which is characterized by unpredictable and recurring seizures. These seizures are the result of abnormal electrical activity in the brain, where there is either an excess of neurotransmitter activity that stimulates neurons or a lack of inhibitory neurotransmitter activity to suppress excessive brain neuron activity.
Detailed Notes on Epilepsy
Definition and Basic Concepts
- Epilepsy: A disorder characterized by recurrent seizures due to abnormal neuronal activity in the brain.
- Seizure: Manifests when there is synchronous activation of neurons that typically wouldn't fire together.
Neuronal Mechanism Underlying Seizures
- During normal neuronal activity:
- Neurons transmit impulses via electrical signals controlled by ions passing through protein channels.
- Neurotransmitters, or signaling molecules, interact with specific receptors to either continue or inhibit the electrical impulse.
Types of Neurotransmitters and Neurons
- Excitatory neurotransmitters: These encourage the opening of ion channels to continue signaling; an example is glutamate.
- Inhibitory neurotransmitters: These cause cells to close channels to stop signaling, such as GABA (gamma-aminobutyric acid).
- Two groups of neurons:
- Transmitting electrical signals
- Blocking electrical signals
Pathophysiology of Epilepsy
- Epileptic seizures occur when inhibitory signals fail in a region, leading to uncontrolled, repeated signals.
- Responsible receptors like NMDA open ion channels for calcium, which intensifies the signal.
- With some patients, mutations make GABA receptors nonfunctional, reducing the brain's ability to suppress these excessive signals.
Types of Epilepsy and Seizures
- Focal Seizures:
- Simple focal seizures: Consciousness is retained.
- Complex focal seizures: Consciousness is altered or lost.
- Jacksonian March: A condition where the seizure starts in one muscle group and spreads to surrounding ones.
- Generalized Seizures:
- Involvement of both brain hemispheres.
- Tonic seizures: Muscles tense up.
- Clonic seizures: Muscles undergo repeated contractions.
- Tonic-clonic seizures: A mix of tonic and clonic phases.
- Atonic seizures: Muscle tone is lost entirely.
- Myoclonic seizures: Quick, short muscle jerks.
- Absence seizures: Characterized by short losses of consciousness without convulsions.
Epileptic Status
- When a seizure lasts longer than five minutes or when seizures occur close together without recovery in between, this is termed "status epilepticus", a life-threatening condition often treated with benzodiazepines.
Diagnostic and Treatment Approaches
- Diagnostic tools: MRI, CT scans, and EEGs help in determining structural or functional abnormalities.
- Treatment:
- Seizures are primarily managed with daily anticonvulsant or antiepileptic drugs.
- Surgery may be necessary for removing tumors or other structural causes of epilepsy.
- Keto diet: Sometimes recommended; it forces the body to use fats rather than carbohydrates, producing ketones for brain energy.
Post-Seizure Conditions
- Transient confusion and Todd's paralysis (temporary postictal paralysis) may occur after recovery from a seizure.
Surveillance and Ongoing Management
- Regular monitoring and adjustments in medication or dietary recommendations are essential based on the patient's lifestyle, age, and type of seizures experienced.
This overview encapsulates the main topics covered about epilepsy, emphasizing the underlying neural mechanisms, types of seizures, management strategies, and the ongoing research into therapies and diagnostics.