Knowing your child’s seizure type can be helpful in understanding the symptoms and directing therapy. There are two main categories of seizures: partial seizures, which are produced by abnormal electrical activity in a region of the brain, and generalized seizures, which are produced by abnormal electrical activity throughout brain.
Partial seizures may be simple, without loss of consciousness, or complex, with some alteration of consciousness. Partial seizures are further defined by their symptoms.
- Partial motor seizures produce clonic movements (shaking) or tonic activity (stiffening) of a limb.
- Partial sensory seizures may cause a child to experience a hallucination, to sense something that is not real such as a strange feeling, an image, a smell, or sounds and voices.
- Autonomic seizures cause disturbances of breathing and circulation.
Partial seizures may be heralded by subtle symptoms, often difficult for the person to describe. For example, some experience a strange rising feeling in their chest or abdomen or an odd taste. These early symptoms of seizure are known as the aura. It is common to have a period of fatigue, headache, or even vomiting after a partial seizure.
Generalized seizures are either primary generalized, which means the whole brain became excited at onset of the seizure, or secondary generalized, which means that the seizures began as a partial seizure in a region of brain and spread to involve the rest of brain.
There are several types of primary generalized seizures:
- Absence seizures cause the child to stare and lose awareness of his/her surroundings. These usually last 10-20 seconds, but may be more prolonged in some children. There is no warning that an absence seizure is coming and the recovery is instant.
- Myoclonic seizures produce lightening-like jerks of the arms or legs. Consciousness may or may not be preserved with myoclonic seizures.
- Atonic seizures cause a sudden loss of body tone and the person falls to the floor. There is usually no warning that an atonic seizure is about to occur and recovery occurs nearly instantly in most cases.
- Generalized tonic seizures produce stiffening of the trunk and limbs, while generalized clonic seizures produce shaking of the trunk and limbs. Many times there is some combination of tonic and clonic movements, these are called generalized tonic-clonic seizures. With tonic or clonic seizures, it is not unusual to see irregularities of breathing and drooling. It is also common with generalized tonic or clonic seizures to have a period of fatigue, headache, confusion, or vomiting after the seizure.
Infantile spasms are a special type of seizure occurring in infants. Infantile spasms typically occur in clusters around awakening from sleep. The baby may have repetitive flexion of the trunk with stiffening of the arms and legs. Others have repetitive elevation of the arms up by the ears as if raising the arms to cheer. There may also be a combination of the two movements.