The brain tissue is composed of millions of nerve cells. The signals from one nerve cell to another are passed through electric current as well as brain chemicals. This all is done in an organized manner. However, in a seizure the electric current between the cells passes in haphazard way. The electrical activity increases abnormally during a seizure. It can happen in one area of brain or in the entire brain cells. When only small part of brain is affected the seizure is referred as partial seizure or focal onset seizure.
A seizure causes host of symptoms such as muscle contraction, blackouts, disturbance in vision, froth in mouth, clenching of jaw etc. When seizures occur repeatedly, we call it epilepsy. Generally a seizure lasts for few seconds or a minute.
Although the exact cause of seizure in many cases remains unknown, certain factors are known to produce seizures. Brain tumor, a scar in brain, heat stroke, low blood sugar, infection of the central nervous system, head trauma, brain stroke etc can trigger a seizure. Focal seizure can be treated with medicines. Person having partial seizure can live a normal life if he takes prescribed anti epileptic medicines as recommended by his physician.
Types And Causes Of Focal Onset Seizures
Focal seizures are of different types. It can be simple focal seizure or complex focal seizure. Seizure is said to be simple partial seizure when a person is aware of his surrounding, remembers every event that occurs during the episode after the seizure has ended.
In complex partial seizure, the person does not remember that he had a seizure afterwards, he is not conscious during this period and he is not aware of his behavior or movement.
Often the cause of seizure is not detected. However, there are many conditions that are known to be associated with this type of seizure. Following are the possible reasons that may trigger a seizure:
- Low blood sugar (hypoglycemia)
- Heat stroke
- Brain tumor
- Head injury
- High blood pressure
- Alcohol withdrawal
- Use of illegal drugs
- Congenital malformation in brain such as cavernous hemangiomas.
- Poison bites from insects and snakes.
- Genetic condition such as phenylketonuria which can cause damage to the brain.
- Infection of the central nervous system such as meningitis. It can be viral or bacterial meningitis.
Signs And Symptoms Of Focal Onset Seizures
The signs and symptoms of focal onset seizures depend on the part of brain involved. There are three different lobes in the brain namely the temporal lobe, frontal lobe, parietal lobe, and occipital lobe. All this lobes have different functions to play. Hence these functions can be affected during the seizure.
Following are the common symptoms of focal seizures:
- Repeated contractions and relaxation of muscles.
- Contraction can occur in one hand and leg of the same side.
- Numbness and tingling in legs and hands.
- Abnormal mouth and tongue movements.
- Abnormal eye movement.
- Difficulty in speaking.
- Repeats words and phrases.
- Rapid movement of eyes.
- Rapid heart and pulse rate.
- Loss of balance
- Pain in abdomen
- Vision impairment
- Face is flushed
- Change of mood
- Sudden blackouts.
Usually a focal seizure does not last for more than one minute. However, if the seizure lasts for a long period of time, the patient needs emergency medical attention.
Diagnosis And Treatment Of Focal Onset Seizures
Focal onset seizure is not difficult to diagnose by the doctor after listening to the patient symptoms as well as from people who have seen the patient’s behavior during the episode. He can then ask for different tests to confirm the diagnosis. These tests include EEG (electroencephalogram), brain scan MRI, spinal tap if needed.
Focal onset seizure can be treated with medications. The main aim of treatment is to reduce the episodes of epilepsy in future so that the patient can live normal life. There are several anti epileptic drugs that may be useful. The physician will recommend the appropriate drug.
Patient has to take this drug on time as prescribed. If he misses the medicine there is risk of an epileptic episode. The patient has to regularly keep follow up with his physician as close monitoring of the patient is necessary for any side effects that develop due to medicines.