From the Guidelines
A seizure is defined as a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. This definition is based on the most recent and highest quality study available, which is the 2024 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations 1. Seizures can vary widely in presentation, from brief lapses of attention or muscle jerks to severe and prolonged convulsions. They can be classified as focal (starting in one area of the brain) or generalized (involving both sides of the brain from the start). Common symptoms include temporary confusion, staring spells, uncontrollable jerking movements of the arms and legs, loss of consciousness or awareness, and cognitive or emotional symptoms such as fear, anxiety, or déjà vu.
Key Points
- Seizures can result from various causes including epilepsy, high fever, head injuries, certain medications, alcohol withdrawal, or low blood sugar.
- A single seizure doesn't necessarily mean a person has epilepsy, which is defined as having two or more unprovoked seizures.
- Understanding the underlying cause of seizures is crucial for proper treatment, which may include anti-seizure medications, surgery, or other therapies depending on the specific diagnosis.
- The International League Against Epilepsy (ILAE) defines epilepsy as having at least two unprovoked seizures occurring more than 24 hours apart, or one unprovoked seizure and a probability of further seizures similar to the general recurrence risk after two unprovoked seizures, occurring over the next 10 years, or diagnosis of an epilepsy syndrome 1.
Classification of Seizures
Seizures can be classified into different types, including:
- Focal seizures: arising within networks of a single cerebral hemisphere and may remain localized or subsequently become more widely distributed 1.
- Generalized seizures: rapidly affect both hemispheres as well as both sides of the body, even when caused by a “focal” lesion 1.
- Unknown onset seizures: seizures for which the onset is unknown or cannot be classified 1.
Importance of Definition
The definition of a seizure is important because it helps healthcare professionals to diagnose and treat seizures accurately. It also helps to distinguish between seizures and other conditions that may have similar symptoms. The American Clinical Neurophysiology Society has established terms and definitions for seizures, including electrographic seizures, electroclinical seizures, and electroclinical status epilepticus 1. These definitions are essential for consistent communication and treatment of seizures.
From the Research
Definition of a Seizure (Convulsion)
- A seizure is defined as 'a sudden surge of electrical activity in the brain, which usually affects how a person appears or acts for a short time' 2
- Seizures are uncontrolled hypersynchronous electrical discharges of neurons in the brain that interfere with normal function 3
- Epilepsy is a condition of recurring seizures that do not have a reversible metabolic cause 3
Key Characteristics of Seizures
- Abnormal electrical discharges from the brain cause recurrent unprovoked seizures 4
- Seizures can be an extremely distressing experience for patients and their families 2
- Seizures can be confused with a variety of other conditions, so an understanding of seizure manifestations is crucial in making an accurate diagnosis 3