Generally, seizures fall into the two categories: focal and generalized seizures. The difference between these types is how they begin.
Focal seizures (previously called partial seizures) start in one part of the brain and affect the part of the body controlled by that part of the brain. It is important to distinguish generalised seizures from focal seizures because the medication to treat them may be different. At times focal seizures can evolve to become generalized seizures.
Primary generalized seizures involve the whole brain and therefore involve the whole body. There are many types of generalized seizures – some convulsive, others nonconvulsive.
Absence seizures (previously called petit mal seizures)
These brief, non-convulsive events involve the whole brain and usually occur in children. With this type of seizure, the person’s awareness and responsiveness are impaired, they simply stare and their eyes might roll back or their eyelids flutter.
It can be difficult to tell the difference between absence seizures and daydreaming. However, absence seizures start suddenly, cannot be interrupted, last a few seconds, and then stop suddenly. And the person resumes what they are doing. Although these seizures last less then 10 seconds, they can occur many times daily, disrupting learning.
Myoclonic seizures –
Myoclonic seizures are brief, shock like jerks of a muscle or a group of muscles, usually lasting no more than a second or two, which at times can result on a fall. There can just one, but sometimes many will occur within a short time. (clusters)
Atonic seizures –
Atonic seizures cause a sudden loss or decrease of normal muscle tone and the person often falls to the ground. Seizures usually last less than 15 seconds. Often called drop attacks, theses seizures can cause head or facial injury. Wearing protective headwear may avoid injury.
Tonic seizures –
Tonic seizures greatly increase normal muscle tone and the body, or legs sudden stiffening movements. These seizures most often occur in clusters during sleep, although they can occur when the person is awake. If the person is standing they will fall quite heavily, often injuring their head. Protective headwear may avoid injury. Seizures usually last less then 20 seconds.
Tonic Clonic seizures (previously called grand mal seizures) –
During a tonic clonic seizure a person’s body stiffens, air being forced past the vocal cords causes a cry or groan and they fall to the ground (the tonic phase). Their limbs then begin to jerk in strong, symmetrical, rhythmic movements (the clonic phase). The person may dribble from the mouth. Go blue or red in the face or lose control of their bladder and/or bowel as the body relaxes.
As consciousness returns, the person may be confused, drowsy, agitated or depressed. They may have a headache and want to sleep. This drowsiness can last for a numbers of hours.
Although this type of seizure can be frightening to watch, the seizure itself is unlikely to seriously harm the person having the seizure. They may, however, vomit or bite their tongue and can sometimes injure themselves if they hit nearby objects as they fall or convulse.
Tonic clonic seizures generally last 1 to 3 minutes. If the active movements of the seizure last more than 5 minutes, it is advisable to call an ambulance.
Prolonged seizures, or a series of seizures without a normal break in between, indicate a dangerous condition called convulsive status epilepticus and demands emergency treatment.
Epileptic spasms –
These are seizures, which are seen more commonly in infants than in older children, and are characterized by brief movement that tend to occur in a cluster when the young person first awakes. The movements involve head dropping and the arms elevating, they may be abdominal ‘crunches’ that also occur. Subtle forms may only involve a jerk/drop of the chin. These are important to distinguish early as they may be associated with regression in development.
Information taken from Epilepsy Australia’s brochure ‘'Diagnosing Epilepsy, answering your questions’. To be reviewed October 2020
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