Seizures are generally described in two major groups of seizures, primary generalized seizures and partial seizures. The difference between these types is in how and where they begin. A new way of naming seizures has been developed by epilepsy specialists, but most often these common names are still used.
Primary generalized seizures begin with a widespread electrical discharge that involves both sides of the brain at once. Hereditary factors are important in many of these seizures.
Partial seizures begin with an electrical discharge in one limited area of the brain. Many different things can cause partial seizures, for example head injury, brain infection, stroke, tumor, or changes in the way an area of the brain was formed before birth called cortical dysplasias. Many times, no known cause is found, but genetic factors may be important in some partial seizures.
Partial seizures can be broken down further, depending on whether a person’s awareness or consciousness (the ability to respond and remember) is affected.
There are six types of generalized seizures. The most common is the generalized convulsion, also called the grand-mal seizure or a tonic-clonic seizure. The patient loses consciousness and usually collapses. The loss of consciousness is followed by generalized body stiffening ,tonic, for 30 to 60 seconds, then by violent jerking, clonic for 30 to 60 seconds, after which the patient goes into the postictal phase. During tonic-clonic seizures, injuries and accidents may occur, such as tongue biting and urinary incontinence.
Absence seizures cause a short loss of consciousness lasting only a few seconds with few or no symptoms. The patient, most often a child, typically interrupts an activity and stares blankly. These seizures begin and end abruptly and may occur several times a day. Patients are usually not aware that they are having a seizure, except that they may be aware of “losing time.”
Myoclonic seizures consist of sporadic jerks, usually on both sides of the body. Patients sometimes describe the jerks as brief electrical shocks. When violent, these seizures may result in dropping or involuntarily throwing objects.
Clonic seizures are repetitive, rhythmic jerks that involve both sides of the body at the same time.
Tonic seizures are characterized by stiffening of the muscles.
Atonic seizures consist of a sudden and general loss of muscle tone, particularly in the arms and legs, which often results in a fall.
The type of treatment prescribed will depend on several factors, including the frequency and severity of the seizures and the person’s age, overall health, and medical history