Understanding Seizures and Status Epilepticus

Definition of Seizure

• A seizure is a transient occurrence of signs and/or symptoms from abnormal, excessive, or synchronous neuronal activity in the brain, often described as an "electrical storm."
• Convulsions refer to the motor act associated with seizures.

Status Epilepticus (SE)

• SE is defined as continuous convulsions lasting more than 5 minutes or serial convulsions with no return of consciousness between them.
• Criteria for SE varies:
  • Generalized tonic-clonic seizures: > 5 minutes
  • Focal seizures with impaired awareness: > 10 minutes
  • Absence seizures: 10-15 minutes.

Types of Seizures

• Acute Symptomatic Seizures: Provoked by immediate factors like electrolyte imbalance; often good prognosis but may signal severe brain issues.
• Unprovoked Seizures: Not linked to an acute issue; first unprovoked seizure has a 30% chance of progressing to epilepsy.
• Remote Symptomatic Seizures: Related to past brain injuries, such as old strokes.
• Reflex Seizures: Triggered by specific stimuli (e.g., flickering lights).

Classification of Epilepsy

• Epilepsy is diagnosed after two or more unprovoked seizures occurring more than 24 hours apart or by one unprovoked seizure if EEG confirms predisposition.
• Epileptic syndromes are classified by specific seizure types, age of onset, EEG findings, and prognosis.

Epileptic Encephalopathy

• Severe EEG abnormalities result in cognitive and developmental impairments.
• Developmental Epileptic Encephalopathy: Both the EEG abnormalities and genetic factors contribute to developmental delays.

Diagnosis and Classification

• ILAE classification involves multiple levels: determining if an event was a seizure, identifying the type of epilepsy, fitting it into a syndrome, and establishing a comprehensive diagnosis.
• Etiology of seizures includes genetic, structural, metabolic, immune, infectious, and undefined origins.
• Comorbidities like developmental delays and psychiatric disorders should be considered.

Types of Epileptic Syndromes

• Genetic Epilepsies: Linked to specific genetic defects; includes childhood absence epilepsy and Dravet syndrome.
• Metabolic Epilepsy: Caused by metabolic disturbances.
• Structural Epilepsy: Resulting from identifiable brain structural issues.
• Immune-mediated Epilepsy: A consequence of inflammation in the CNS treatable with immunotherapies.
• Infectious Epilepsy: Relating to chronic infections rather than acute ones.

Seizure Types and Clinical Features

• Seizure classification involves examining age of onset, seizures' characteristics, and EEG results, which assist in prognosis and treatment.
• Types include:
  • Partial Seizures: Simple (consciousness retained) and complex (impaired consciousness).
  • Generalized Seizures: Affect both hemispheres of the brain.

Generalized Tonic-Clonic Seizures

• Often presents suddenly with loss of consciousness; includes a tonic phase followed by a clonic phase.
• Postictally, patients remain semicomatosely in deep sleep, often with headaches and vomiting.

Myoclonic Epilepsies of Childhood

• Characterized by brief, symmetric muscle contractions; may result in fall or slumping forward.
• Can vary from benign in childhood to serious in adults.

Laboratory Tests for Seizures

• Essential tests include serum electrolytes, toxicology screening, metabolic testing, glucose levels, EEG, lumbar puncture, skull X-ray, and neuroimaging (preferably MRI).

Indications for Brain Imaging

• Urgent CT or MRI is necessary for focal seizures, postictal deficits, lack of return to baseline, trauma before seizures, or high-risk medical histories.