Seizures l: Introduction

Understanding seizures and epilepsy relies on key definitions that help in recognizing, classifying, and managing these disorders. These definitions provide a framework for recognizing, classifying, and managing seizure disorders.

Definitions

A seizure is a sudden, abnormal burst of electrical activity in the brain that can cause changes in awareness, movement, sensation, or behavior, depending on the area involved. Epilepsy is a chronic condition characterized by recurrent, unprovoked seizures, reflecting an underlying tendency of the brain to generate abnormal electrical activity due to genetic, structural, or metabolic causes. A convulsion is a seizure characterized by intense, involuntary muscle contractions; not all seizures are convulsive, such as absence seizures.

Classification of Seizures

Seizures are classified as provoked or unprovoked. Provoked seizures occur due to identifiable causes like trauma, infection, or metabolic disturbances, while unprovoked seizures are not linked to immediate triggers and are often associated with epilepsy. Focal seizures originate in a specific brain region and may occur with preserved awareness (causing unusual sensations) or impaired awareness (leading to staring or repetitive movements). Generalized seizures involve both hemispheres from onset and always impair consciousness, including tonic-clonic, absence, myoclonic, atonic, tonic, and clonic types.

Additional Key Terms

Other important terms include epileptic spasms, seen mainly in infants as sudden body movements in clusters; aura, a warning sensation before some focal seizures; postictal state, the recovery phase marked by confusion or drowsiness; and status epilepticus, a medical emergency involving prolonged or repeated seizures without recovery.