Medical seizures range in severity and have a number of potential causes. there are two main classes of seizures: epileptic, which are caused by a seizure disorder, and non-epileptic, which are caused by other factors, according to the Merck Manual. These can include fevers, medications or infections. There are also several sub-types of medical seizures, each with its own characteristics.
Partial Seizures
Partial seizures may be classified as simple or complex. The Mayo Clinic reports that partial seizures occur in only one segment of the brain. They are sometimes called focal seizures. The National Institutes of Health report that simple partial seizures do not affect the memory, while complex partial seizures may cause some blacking out. A person having a simple partial seizure may experience twitching in a limb, or may have temporarily altered sensations (such as taste or vision). A person having a complex partial seizure may perform repeated movements that seem to have no purpose, or he may stare off into space.
Petit Mal Seizures
Petit mal seizures, also known as absence seizures are a form of generalized seizure, which involves the entire brain. Like a complex partial seizure, they may cause a person to stare and may also cause a loss of consciousness. A person having a petit mal seizure may suddenly stop what they are doing, and resume the same activity a few moments later, according to the NIH.
Myoclonic Seizures
Myoclonic seizures, according to the Mayo Clinic, cause sudden twitches in the arms or legs. The Merck Manual adds that myoclonic seizures may also involve the trunk. During a myoclonic seizure, which is usually brief, a person usually remains conscious and able to interact. Repeated myoclonic seizures, however, may trigger a more intense type of seizure.
Atonic Seizures
Atonic seizures cause decreased muscle tone. According to the Merck Manual, most of these types occur in children. An atonic seizure causes the person to fall down due to decreased muscle control; however, they do not experience unusual twitching movements. Atonic seizures usually cause a short loss of consciousness.
Tonic Seizures
Tonic seizures cause a person's muscles to stiffen or become rigid, according to the Merck Manual. This may happen gradually or suddenly and often takes place while the person is sleeping. If the person is awake, however, they typically do not lose consciousness. Tonic seizures occasionally cause jerking movements, but this is not common.
Grand Mal Seizures
A grand mal seizure, also known as a tonic-clonic seizure, is often the first type of seizure that comes to people's mind. According to the Mayo Clinic, it is the most intense type of seizure. During a tonic-clonic seizure a person loses consciousness. They often experience muscle rigidity and jerking muscles. In other words, while they may become stiff, they may also experience violent shaking at the same time. Some people may lose control of their bladder during a tonic-clonic seizure. According to the NIH this type of seizure may last for several minutes and may also be followed by a period of weakness which can last up to two days.
