Epilepsy is a neurological condition involving the brain that makes people more susceptible to having recurrent unprovoked seizures. It is one of the most common disorders of the nervous system and affects people of all ages, races and ethnic background. According to the CDC, almost 3 million Americans live with epilepsy and nearly 200,000 people in the U.S. develop this condition annually.
Anything that interrupts the normal connections between nerve cells in the brain can cause a seizure; this includes a high fever, low blood sugar, alcohol or drug withdrawal, or a brain concussion. Under these circumstances, anyone can have one or more seizures. However, when a person has two or more recurrent unprovoked seizures, he or she is considered to have epilepsy. There are many possible causes of epilepsy, including an imbalance of nerve-signaling chemicals called neurotransmitters, tumors, strokes, and brain damage from illness or injury, or some combination of these. In the majority of cases, there may be no detectable cause for epilepsy.
What Is a Seizure?
The brain is the center that controls and regulates all voluntary and involuntary responses in the body. It consists of nerve cells that normally communicate with each other through electrical activity.
A seizure occurs when part(s) of the brain receives a burst of abnormal electrical signals that temporarily interrupts normal electrical brain function.
What Are the Different Types of Seizures?
The type of seizure depends on which part and how much of the brain is affected and what happens during the seizure. The two broad categories of epileptic seizures are generalized seizures (absence, atonic, tonic-conic, myoclonic) and partial (simple and complex) seizures. Within these categories, there are several different types of seizures in children, including:
Focal seizures. Focal seizures take place when abnormal electrical brain function occurs in one or more areas of one side of the brain. Focal seizures may also be called partial seizures. With focal seizures, particularly with complex focal seizures, the child may experience an aura before the seizure occurs. The most common aura involves feelings such as dejavu, impending doom, fear, or euphoria. Visual changes, hearing abnormalities, or changes in the sense of smell can also be auras. Two types of partial seizures include:
Simple focal seizures. The child may show different symptoms depending upon which area of the brain is involved. If the abnormal electrical brain function is in the occipital lobe (the back part of the brain that is involved with vision), the child’s sight may be altered. However, more commonly, a child’s muscles are affected. The seizure activity is limited to an isolated muscle group, such as fingers or to larger muscles in the arms and legs. Consciousness is not lost in this type of seizure. The child may also experience sweating, nausea, or become pale.
Complex focal seizures. This type of seizure commonly occurs in the temporal lobe of the brain, the area of the brain that controls emotion and memory function. This seizure usually lasts one to two minutes. Consciousness is usually lost during these seizures. Losing consciousness may not mean that a child passes out–sometimes, a child stops being aware of what’s going on around him or her. The child may look awake but have a variety of behaviors. These behaviors may range from gagging, lip smacking, running, screaming, crying, and/or laughing. When the child regains consciousness, he or she may complain of being tired or sleepy after the seizure. This is called the postictal period.
Generalized seizures. Generalized seizures involve both sides of the brain. There is loss of consciousness and a postictal state after the seizure occurs. Types of generalized seizures include the following:
Absence seizures (also called petit mal seizures). These seizures are characterized by a brief altered state of consciousness and staring episodes. Typically the child’s posture is maintained during the seizure. The mouth or face may move or the eyes may blink. The seizure usually lasts no longer than 30 seconds. When the seizure is over, the child may not recall what just occurred and may go on with his/her activities, acting as though nothing happened. These seizures may occur several times a day. This type of seizure is sometimes mistaken for a learning problem or behavioral problem. Absence seizures almost always start between ages 4 to 12 years.
Atonic (also called drop attacks). With atonic seizures, there is a sudden loss of muscle tone and the child may fall from a standing position or suddenly drop his/her head. During the seizure, the child is limp and unresponsive.
Generalized tonic-conic seizures (also called grand mal seizures). The classic form of this kind of seizure, which may not occur in every case, is characterized by five distinct phases. The body, arms, and legs will flex (contract), extend (straighten out), tremor (shake), a conic period (contraction and relaxation of the muscles), followed by the postictal period. Not all of these phases may be seen with every one of this type of seizure. During the postictal period, the child may be sleepy, have problems with vision or speech, and may have a bad headache, fatigue, or body aches.
Myoclonic seizures. This type of seizure refers to quick movements or sudden jerking of a group of muscles. These seizures tend to occur in clusters, meaning that they may occur several times a day, or for several days in a row.
Infantile spasms. This rare type of seizure disorder occurs in infants from before six months of age. There is a high occurrence rate of this seizure when the child is awakening, or when they are trying to go to sleep. The infant usually has brief periods of movement of the neck, trunk, or legs that lasts for a few seconds. Infants may have hundreds of these seizures a day. This can be a serious problem, and can have long-term complications.
Febrile seizures. This type of seizure is associated with fever and is not epilepsy, although a fever may trigger a seizure in a child who has epilepsy. These seizures are more commonly seen in children between 6 months and 5 years of age and there may be a family history of this type of seizure. Febrile seizures that last less than 15 minutes are called “simple,” and typically do not have long-term neurological effects. Seizures lasting more than 15 minutes are called “complex” and there may be long-term neurological changes in the child.