What is epilepsy?
Epilepsy is a chronic disorder that causes unprovoked, recurrent seizures. A seizure is a sudden rush of electrical activity in the brain.
There are two main types of seizures. Generalized seizures affect the whole brain. Focal, or partial seizures, affect just one part of the brain.
Causes of epilepsy
Epilepsy may develop after a brain injury or insult. Severe lack of oxygen at birth (asphyxia), head injury, brain infections (meningitis and encephalitis) may lead to epilepsy. This is called symptomatic epilepsy or secondary epilepsy.
In many individuals epilepsy may develop without any identifiable cause and then it is called idiopathic epilepsy or primary epilepsy.
Cryptogenic epilepsy is a condition when no evidence of damage to the brain can be found, but other symptoms, such as learning difficulties, suggest that damage to the brain has occurred.
Symptoms of epilepsy
Seizures are the most common symptom of epilepsy. A seizure is a result of excessive nerve-cell discharges in the brain. When there is excess discharge of tiny microscopic electric impulses in the brain at a region, they travel fast all over the brain via neurons. During a seizure, the electrical impulses are disrupted, which can cause the brain and body to behave abnormally.
The severity of the seizures can differ from person to person. While some may go into a “trance like” stage for a few seconds or minutes, others may lose consciousness. Yet others may have convulsions or uncontrollable shaking of the body.
Types of epilepsy
Seizures are divided into two main types - generalized and partial. Generalized seizures occur if the abnormal electrical activity affects all or most of the brain. This affects most of the body. A tonic-clonic seizure is the most common type of generalized seizure. The whole body stiffens and the person loses consciousness and falls. This is followed by a violent uncontrollable shaking. Absence seizure is another type of generalized seizure. The person may lose consciousness or awareness. This is common in children. Other types include a myoclonic seizure, a tonic seizure and an atonic seizure.
Partial seizures are also called focal seizures. Here only one part of the brain is affected. There may be localized (focal) symptoms. These may be simple partial seizures or complex partial seizures.
Sometimes a partial seizure develops into a generalized seizure. This is called a secondary generalized seizure.
Diagnosis of epilepsy
Epilepsy is most often diagnosed after more than one seizure or fit. Description of the seizure and its video recording often helps to diagnose the type of epilepsy. Scans of the brain using CT scans and MRI are used to detect visible brain damage. EEG or Electro Encephalogram is used to detect the electrical activities of the brain.
Epilepsy generally has no cure. There are however several medications that can be used to control seizures. These are known as anti-epileptic drugs (AEDs). In around 70% of cases, seizures are successfully controlled by AEDs. The right dose and combination or type of drug may require some trials and adjustments. In some cases, surgery may be used to remove the area of the brain affected or to install an electrical device that can help control seizures.