Understanding epilepsy

More than 10 million persons suffer from epilepsy in India. Epilepsy is one of the most common neurological disorders causing unprovoked recurrent seizures. There are about 70 million people around the globe affected by epilepsy and more than 10 million in India. Genetic causes are responsible for almost 70-80% of epilepsy cases and in the remaining 20-30% cases, acquired conditions such as stroke, tumour or head injury may be the reason.

Causes for childhood epilepsy

Injury to the brain before, during or after birth, such as developmental defects of the brain, perinatal brain injury due to bleeding or lack of oxygen or traumatic injury of the brain early in neonatal life

Genetic defects

Degenerative disorders that affect the brain

Metabolic and chemical disorders

Infections of the nervous system

Brain tumours and clots

Toxic reactions to drugs and other substances

Types of treatment

Medication: It is usually the first choice of treatment and the majority of children with different forms of seizures are controlled with anti-epileptic drugs (AED). Almost 80% of children respond well to some form of oral medication, and newer anti-epileptics that have fewer side effects are available.

Surgery: If the patient doesn’t respond to drugs, surgery to remove a small portion of the brain where the seizures originate can be considered. The chances of eliminating seizures after surgery range from 60% to 70%. While most children make remarkable recoveries after such surgeries, they sometimes suffer weakness on one side of the body.

Special diet: Sometimes, a special diet can be considered for children who don’t respond to anti-epileptic medication and who are not good candidates for surgery. The ketogenic diet, which is high in fat and low on carbohydrates, mimics a fasting state and forces the body to use fat rather than carbohydrates as an energy source. The ketogenic diet has been used for nearly 100 years to control epileptic seizures.

Prognosis

Children who have mild brain injury will outgrow their seizures in the first month. However, a small percentage will go on to develop difficult-to-treat seizures that can be lifelong.

Generally speaking, 50% to 75% of children with epilepsy will eventually have a completely seizure-free life. Remission is more likely if there is no underlying neurological deficit present, seizure frequency is low, and response to anti-epilepsy medication is good.

About 20% of children with epilepsy will have intellectual disabilities. Their epilepsy tends to persist throughout their lives with a low rate of remission. Behavioural and psychiatric problems, such as attention deficit-hyperactivity disorder, autism, depression and anxiety, are also common.

Role of genetics

Advances in genetics have transformed the diagnosis and treatment of epilepsy. It has been proven that inherited epilepsy occurs even without a family history and it can affect anyone irrespective of age and gender. Genetic changes in certain genes in the brain can result in brain malformations leading to epilepsy or epilepsy can also be caused due to any abnormality in sodium or calcium channel controlling gene. Scientists have identified many genes that contribute to different paediatric epilepsy syndromes,

Certain paediatric epilepsies are resistant to medication and sometimes multiple drugs are needed to control such epilepsy syndromes. But now medications that are tailored for specific genetic mutations are on the horizon and they have changed how the condition is treated. Genetic testing helps medical experts decide the most suitable medication to control the seizures, to plan a customised diet and minimise the necessity of invasive testing.

Despite the availability of antiepileptic drugs (AEDs), there is a large treatment gap among patients with epilepsy. For treatable epilepsy, this treatment gap can be attributed to poor education, poverty, cultural beliefs, stigma, and poor healthcare infrastructure; whereas for chronic epilepsy, this gap can be attributed to lack of proper diagnosis and treatment. The limitation of genetic testing is accessibility and availability of such test and the cost for the same.

(The author is consultant clinical
geneticist, MedGenome Labs)