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Seizures (or convulsions) are temporary alterations in brain functions due to abnormal electrical activity of a group of brain cells that present with apparent clinical symptoms and findings. An isolated abnormal electrical activity recorded by an electroencephalography examination without a clinical presentation is not called a seizure.
Seizures can cause involuntary changes in body movement or function, sensation, awareness, or behavior. A seizure can last from a few seconds to a few minutes. There are more than 20 different types of seizures.
Seizures are often associated with epilepsy and related seizure disorders.
Seizure is often associated with a sudden and involuntary contraction of a group of muscles. However, a seizure can also be as subtle as marching numbness of a part of body, a brief loss of memory, sparkling of flashes, sniffing an unpleasant odor, a strange epigastric sensation or a sensation of fear. Therefore seizures are typically classified as motor, sensory, autonomic, emotional or cognitive.
Some seizure types are:
Symptoms experienced by a person during a seizure depend on where in the brain the disturbance in electrical activity occurs. Some seizures may be frightening to onlookers. A person having a tonic-clonic (grand mal) seizure may cry out, lose consciousness and fall to the ground, and convulse, often violently. A person having a complex partial seizure may appear confused or dazed and will not be able to respond to questions or direction. Some people have seizures that are not noticeable to others. Sometimes, the only clue that a person is having an absence (petit mal) seizure is rapid blinking or a few seconds of staring into space.
It is still disputable whether a febrile seizureA febrile seizure also known as a fever fit or febrile convulsion is a generalized convulsion caused by elevated body temperature. They most commonly occur in children below the age of three years old and should not be diagnosed in children under the age has to be regarded as an epileptic disorder or not. In general, a patient with two or more episodes of seizures is accepted to have epilepsy (a condition also known as a seizure disorder.) Many people with epilepsy perceive " aurasFor other meanings, see Aura (disambiguation). An Aura is an optical effect wherein gas or dust surrounding an object luminesces or reflects light from the object. The visual disturbance seen by about half of all migraine sufferers is also called aura .": telltale sensations such as strange lights, unpleasant smells or odd sensations before their seizures.
Major causes of seizures include head trauma, infection, tumors, metabolic alterations (e.g. low or high blood glucose levels), and as part of the withdrawal symptoms associated with certain classes of addictive drugs, especially sedativeA sedative is a drug that depresses the central nervous system (CNS), which causes calmness, relaxation, reduction of anxiety, sleepiness, slowed breathing, slurred speech, staggering gait, poor judgment, and slow, uncertain reflexes. Sedatives may be refs such as alcoholIn general usage, alcohol (from Arabic al-khwl , or al-ghawl ) refers almost always to ethanol, also known as grain alcohol and often to any beverage that contains ethanol (see alcoholic beverage . This sense underlies the term alcoholism ( addiction to a, barbiturates and benzodiazepines. Some medications produce an increased risk of seizures and electroconvulsive therapy (ECT) deliberately sets out to induce a seizure. Many seizures have unknown causes.
Seizures in pregnancy can be a sign of eclampsia.