Epilepsy attacks: types and features
What are epileptic seizures? How do myoclonic , tonic, clonic and other seizures manifest themselves in children and adults?
Depending on the type of epilepsy, as well as the cause of the disease, patients may experience different types of seizures. It is important to remember that the same patient may experience various epileptic seizures.
Types of seizures in epilepsy
All seizures of epilepsy are divided into focal (focal, partial) and generalized. Focal seizures occur due to the localization of abnormal electrical activity in a certain area of the brain, and generalized ones are characterized by the spread of this activity to both hemispheres.
According to clinical signs, epileptic seizures are also divided into:
Myoclonic seizures are characterized by rapid twitching of various muscle groups. Most often they are bilateral and symmetrical, but they can also be single. Twitching can occur in various muscle groups, but is most commonly seen in the shoulder girdle and arms, affecting the extensor muscle groups.
During an attack, patients may drop objects from their hands or involuntarily throw them aside. For example, patients complain that a cup or fork falls out of their hands during breakfast or a toothbrush while washing. Often, neither children nor adults attach much importance to this at first, thinking that this refers to problems with coordination or lack of sleep.
If the attack is localized in the legs, then patients may fall, as if they were hit under the knees or pushed.
Myoclonic seizures ( myoclonus ) may present as:
- Flexion – Patients shake their heads or flex their arms.
- Extension – with this type of attack, patients unbend their arms or spread them to the side. At the same time, the fists are also unbent.
- Spasms of the occiput – the head is thrown back and can be bent rhythmically. As a rule, these attacks occur in series of about 10 seconds.
Tonic convulsions are sharp muscle contractions during which a limb or the entire body freezes in one position. This type of seizure can be localized (when seizures occur in a specific part of the body, such as the arm) or generalized (affect the entire body).
Most often, tonic seizures occur in children with diagnoses: West syndrome, Lennox – Gastaut syndrome and Otahara syndrome .
They appear as irregular and rapid muscle contractions that follow each other after a short period of time.
Clonic convulsions are often found in focal forms of epilepsy. However, in some cases, it may occur in patients with a generalized type of disease. This happens due to the rapid spread of electrical activity in both hemispheres of the brain.
Clonic seizures are common in children diagnosed with Dravet syndrome . In children under 1 year of age, clonic seizures may not manifest themselves, and the disease is expressed in febrile paroxysms with a focal component. After 3-5 years, clonic convulsions may appear, which can change the side of the lesion even during one attack.
Tonic-clonic seizures are mixed paroxysms that combine tonic spasms and rapid clonic contractions. In epilepsy, these seizures occur when abnormal epileptic activity in the brain extends to both hemispheres. Many of these seizures begin as focal in the cerebral cortex and then spread to become generalized .
Some of these attacks begin with myoclonic twitches in certain parts of the body, and then acquire the usual course.
A tonic-clonic seizure consists of 3 phases:
Tonic Phase – During the tonic phase, the patient’s body tenses up and the back arches. In this case, the patient may scream, involuntary urination and biting of the tongue may occur.
Clonic phase – during the clonic phase, the muscles begin to contract
sharply and rapidly, causing the patient to make convulsive jerky movements. At
the same time, frothy saliva may be released from the mouth, and the eyes begin
to blink actively.
Postictal state – after an attack, patients experience drowsiness, weakness in the limbs, as well as general exhaustion. In this condition, the patient needs rest to recuperate.
In some cases, before an attack, patients may experience an aura, which is a harbinger of an attack. Each patient may have an individual aura, you can learn about the types of which in the article – “Aura in epilepsy”.
Atonic seizures are characterized by a sudden loss or weakening of muscle tone. They can be either limited, when a certain part of the body is involved (arms, legs, head), or generalized.
According to the duration, 2 types of atonic seizures are distinguished:
- Short – in most cases, affect only one muscle group, and if they lead to a fall, then the patient can rise on his own after an extremely short period of time.
- Prolonged – last from one to several minutes. With this type of seizure, loss of consciousness and falls are more common.
Atonic seizures occur in both generalized and focal types of epilepsy. In particular, these attacks can manifest themselves in Lennox – Gastaut syndrome and Dravet syndrome .
It should be noted that atonic seizures can be a component of other types of seizures, for example, absences . Some patients who have been diagnosed with status epilepticus of slow -wave sleep suffer from absences with an atonic component of certain muscle groups.
Why do epileptic seizures occur?
The brain is made up of nerve cells – neurons that are capable of generating and also conducting electrical impulses. In the brain of healthy people, impulses are distributed evenly and smoothly distributed along the chains of neurons. However, in patients with epilepsy, neurons are able to generate electrical impulses of greater strength than necessary – this becomes the cause of an epileptic seizure.
Abnormalities that occur during a seizure may indicate an area of the brain where abnormal electrical activity occurs.