3.27
Convulsões l: Introdução
Compreender convulsões e epilepsia depende de definições-chave que ajudam a reconhecer, classificar e controlar esses transtornos. Essas definições fo…
Uma convulsão é um episódio transitório de atividade elétrica anormal e excessiva no cérebro que prejudica a função neurológica normal. Epilepsia é um distúrbio em que a pessoa tem tendência a longo prazo de ter convulsões repetidas e não provocadas.
Algumas convulsões causam convulsões — tremores violentos devido a contrações musculares rápidas. Outros podem ser mais sutis, mas menos facilmente reconhecíveis.
As crises focais começam em uma região específica do cérebro e podem ou não prejudicar a percepção. Quando a consciência é preservada, sintomas sensoriais como formigamento ou cheiros incomuns são clinicamente chamados de aura.
Convulsões generalizadas afetam ambos os lados do cérebro ao mesmo tempo. Uma pessoa pode desabar, enrijecer e se sacudir ritmicamente.
Um pródromo pode aparecer horas antes com sintomas inespecíficos, como mudanças de humor ou dores de cabeça. O estado pós-ictal é um período temporário após uma convulsão, frequentemente marcado por confusão ou fadiga.
Status epiléptico é uma emergência com risco de vida definida como uma convulsão que dura mais de cinco minutos ou convulsões repetidas sem recuperar a consciência entre os episódios.
View the full transcript and gain access to JoVE Core videos
Q1: What is the difference between a seizure and epilepsy?
A seizure is a transient episode of abnormal, excessive electrical activity in the brain that disrupts normal neurologic function. Epilepsy is a chronic disorder in which a person has a long-term tendency to have repeated, unprovoked seizures due to genetic, structural, or metabolic causes. Not everyone who experiences one seizure develops epilepsy.
Q2: What are the main types of seizures based on brain location?
Focal seizures begin in a specific brain region and may preserve awareness, causing sensory symptoms like tingling or unusual smells called an aura. Generalized seizures affect both brain hemispheres simultaneously and always impair consciousness, often causing a person to collapse, stiffen, and jerk rhythmically. These classifications help guide treatment and prognosis.
Q3: What is an aura and when does it occur?
An aura is a warning sensation or sensory symptom that may occur before some focal seizures when awareness is preserved. Common auras include tingling sensations, unusual smells, visual disturbances, or other perceptual changes. The aura provides patients with advance notice that a seizure may be beginning.
Q4: What happens during the postictal state after a seizure?
The postictal state is a temporary recovery period following a seizure, often marked by confusion, fatigue, or drowsiness. During this phase, the brain gradually returns to normal function. The duration and severity of postictal symptoms vary depending on seizure type and individual factors.
Q5: What is status epilepticus and why is it dangerous?
Status epilepticus is a life-threatening medical emergency defined as a seizure lasting more than five minutes or repeated seizures without regaining consciousness between episodes. This prolonged abnormal electrical activity can cause brain damage and requires immediate medical intervention. Increased intracranial pressure may develop during this critical state.
Q6: What is a convulsion and how does it differ from other seizures?
A convulsion is a seizure characterized by intense, involuntary muscle contractions causing violent shaking and rapid muscle movements. However, not all seizures are convulsive; some seizures, such as absence seizures, involve minimal movement or no visible muscle contractions despite abnormal brain electrical activity occurring.
Q7: What warning signs might appear before a seizure occurs?
A prodrome may appear hours before a seizure begins, presenting nonspecific symptoms like mood changes, headaches, or irritability. These early warning signs differ from an aura, which occurs immediately before focal seizures with preserved awareness. Recognizing prodromes can help patients prepare for potential seizures.