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Epilepsy-International Classification of seizures, types

TYPES OF SEIZURES                                               

Types of epilepsy seizures

Partial seizures

These originate in one of the lobes of the brain. There are two types of partial seizure

simple and complex – and each manifests itself in the patient according to the part of the brain from which it originated.
Simple partial seizures– These originate in the lobes of the brain

Patients may say they are having an aura, or warning, in cases it may be an epigastric sensation;

– Consciousness is not impaired;

– Some patients report a tingling or numbing sensation, while others report flashing lights.

– In some patients there is posturing of the upper and lower limbs, which may extend outwards, and the head may turn to one side;

– Patients who have no warning will fall to the floor if they are standing. A phase of involuntary motor movements may follow of which the patient usually is totally unaware.

Complex partial seizures last from a couple of minutes to several days in a few extreme cases.

The involuntary movements (automatisms) may present differently in different patients. Some may have verbal automatisms, making noises, meaningless sounds, grunts, or whistling noises, others may clearly repeat words or sentences.

Some patients may demonstrate ambulatory automatisms such as walking about the room or running very quickly when least expected. Oro-alimentary auto-matisms involve the oro-facial muscles, and include chewing movements, lip smacking, and swallowing movements.

Patients may show signs of fear or laughter, known as mimicry automatisms. Other automatisms cause patients to fiddle with their hands, clothes, or objects in the room, or they may tap, pat or rub objects. This could become serious if a patient were in an acute hospital ward near vital life-saving equipment. Some patients may start undressing or fiddling with themselves in the genital area. Violent automatisms can occur, but these are usually a result of the patient being acutely confused as a consequence of the seizure. Some patients become violent if they are restrained. A person who is having a complex partial seizure is often mistaken by the public or emergency response teams as being drunk or having taken drugs.

Generalised seizures

Generalised seizures differ from partial seizures in that they involve both hemispheres of the brain at onset. Patients never have a warning with generalised seizures and consciousness is almost always impaired from the start. The various types of generalised seizure are discussed below.

Absence seizures

These used to be called ‘petit mal’ seizures but this is discouraged today. Absence seizures may be typical or atypical.

Typical absence seizures

These are characterised as follows

  • Patients will suddenly stop what they are doing and lose consciousness for the duration of the event. They do not usually fall if they are standing;
  • Patients appear to have a gazed or vacant expression on their face, with drooping of their eyelids. They are totally unaware of their surroundings;
  • There may be very subtle jerks of the eyelids and/or slight tremor in the limbs. The seizure lasts about 10 seconds then stops as abruptly as it started;
  • Patients can normally continue with whatever they were doing before the seizure.

Atypical absence seizures

  • These are longer in duration than a typical absence seizure – sometimes up to 45 seconds;
  • The changes noted in the typical absence group tend to be more apparent in atypical absences, with a longer recovery time;
  • Loss of awareness is not always complete.

Many absence seizures go unnoticed to an onlooker. But should the patient go on to have an atypical absence seizure that lasts, say, 40 seconds while crossing a busy road, he or she will require assistance, as both the patient and other road users are at risk.

Myoclonic seizures

  • A myoclonic seizure is a ‘brief contraction of a muscle, muscle group or several muscle groups caused by cortical discharge’ some patients may have only a single ‘jerk’, while others may have many in a cluster, or a continuous spasm;
  • Myoclonic jerks are sometimes strong enough to throw patients out of bed or a chair, and if they are standing, they could be thrown to the floor by the jerking movement. They may utter a very brief vocal noise at the time of the jerk;
  • As these seizures last for less than five seconds, a single myoclonic jerk may go unnoticed. It is not until they cluster that they become noticeable. They may lead into a generalised tonic clonic seizure;
  • The muscles involved in the myoclonic jerks are generally those in the arms, legs, torso and face, but some patients’ bladder or bowel muscles are affected and they may try to get to the toilet for fear of being incontinent.
  • Because of the nature of the jerks in patients having a myoclonic seizure, they may harm themselves; for example, if they are holding a hot drink they may scald themselves (or others who happen to be close by); or if they fall they may sustain injury to their knees, ankles or face.

Many people who do not have epilepsy experience involuntary jerks as they are going to sleep. It is important to stress that this is a normal physiological phenomenon and not epilepsy.

Atonic seizures

These occur as a result of sudden loss of tone in the postural muscles (They are characterised as follows:

  • The patient will drop to the floor if standing, and if seated will slump in the chair;
  • Consciousness will be lost for a split second; in most cases the patient can get up again straightaway.
  • Common injury sites are the ankles, knees and chin area of the face. In some cases fractures are sustained at the sites of impact.

Tonic seizures

These are characterised as follows

  • A sudden increase in the body’s muscle tone causes the muscles to contract;
  • The neck extends, but it does not rotate to either side;
  • The upper limb muscles contract forcing the arms and shoulders to abduct and elevate. The upper parts of the arms usually come alongside the ears, but in some cases the arms will stretch down to the floor;
  • The patient’s hands will abnormally posture, either being clenched in a fist shape or flexed open with fingers extended outwards;
  • The facial muscles contract, which cause the eyes to open and the eyeballs to rotate upwards;
  • The muscles involved in respiration contract, forcing air out of the lungs, which can be heard as a cry. This is followed by a short phase of apnoea, during which consciousness is lost;
  • The patient’s legs extend outwards. Patients who are standing will fall to the floor.
  • Tonic seizures are brief and for some patients consciousness is regained before they hit the floor. The most common injury tends to be to the patient’s head. As with any head injury, post-seizure care involves recording neurological observations and using a recognised recording scale, such as the Glasgow Coma Scale. Recordings should continue until they are reviewed by a doctor, or if the patient has obviously recovered.

Clonic seizures

These are characterised by asymmetrical jerking, without any prior stiffening.

Tonic clonic phase

Tonic clonic seizures

Tonic clonic seizures are the most dramatic form of epileptic seizure, and are usually the type nurses fear the most. These used to be called ‘grand mal’ fits. There are two stages – tonic and clonic. The characteristics of the tonic phase have already been described above.

All the movements characteristic of the tonic phase will occur at the same time, and will continue for up to 30 seconds before the seizure proceeds into the clonic phase, the characteristics of which are as follows

  • Convulsive movements, usually involving all four limbs and the facial muscles, may be seen. The limbs abduct and extend repeatedly for up to 60 seconds. These movements then diminish in strength and slow down in frequency;
  • Breathing is impaired, and because the muscles involving breathing have contracted, air is expelled, generating a noise as it does so;
  • Excessive salivation may present as frothing at the mouth;
  • Changes in some autonomic functions occur as a result of the assault on the body described above; for example, the pulse rate and blood pressure increase and may take time to return to normal;
  • A period of rest follows the above activity, after which the patient’s muscles relax and become flaccid;
  • Breathing becomes stertorous and may last from two to 25 minutes;
  • Consciousness is regained slowly;
  • Patients remain confused for some time after the seizure and drift off into a deep sleep.
  • Some patients will be incontinent of urine or faeces during a seizure. On recovery, they may report headaches and sore muscles. It may be several days before some patients feel better.
  • Some patients drift off to sleep after the seizure but it is important to note whether or not this is normal for them, because they may have sustained some form of internal trauma that is causing them to slip into unconsciousness.
  • Some patients may start to have another seizure while they are being observed, their breathing may become very shallow, or they may stop breathing during the sleep phase. At this stage, respiratory arrest procedures must be implemented according to local policy.

Unclassifiable seizures

There are many other epileptic seizures that do not fit clearly into either of the above groups. While seizures of whatever type can be frightening, most are self-limiting and will stop without any intervention other than good nursing care. Some seizures recur at frequent intervals, but the patient fully recovers in between. Seizures can also occur in clusters, occurring at certain times; for example, in the case of female patients at the time of their menstrual period.