Dr. Chidambaramurthy Udaya Shankar, Senior Consultant – Neurology, Sakra World Hospital

Epilepsy, a chronic non-communicable disease of the brain is one of the most common neurological disorders in the world. It comes with recurrent seizures – brief episodes of involuntary movement of either the whole body or a part of the body accompanied by loss of consciousness and control of bladder and bowel function. Epilepsy amps up the risk of premature death by almost three times.

A seizure is a repeated and uncontrolled burst of electrical activity between brain cells or neurons that results in temporary abnormalities in the tone of muscles and muscle movements like stiffness, twitching to limpness, behaviours, sensations or states of awareness. Not all seizures are same. Seizures can be a single event as well as a recurring one. When it occurs again and again, it is known as epilepsy.

In order to get appropriate and accurate seizure diagnosis it is essential to identify the various characteristics and kinds of seizures. Identifying the seizure kinds helps in apt identification of the causes and thereby plan for an effective treatment approach.

The various kinds of seizures and their characteristics

• Focal or partial seizures: Also known as partial seizures, focal seizures usually begin in one area of the brain and are caused by any type of focal injury that leaves scar tangles. The most common causes of focal seizures as identified by an MRI or medical history include trauma, stroke and meningitis. Children may get focal seizures when there are developmental scars that occur as part of fetal and early brain growth.
• Generalised onset seizures: These kinds of seizures could be genetic but only a handful of people with generalised onset seizures have family members with similar condition. However, the risk of generalised onset seizures increases among children with family members suffering from the same. Severity of this kind of seizures vary from one person to person. A genetic testing may help doctors to identify the causes. Inadequate sleep and excessive alcohol consumption can increase the risk of generalised onset seizures especially among those who are genetically prone to it.

Generalised onset seizures have several categories:

• Absence seizures or Petit Mal seizures: This kind of seizures refer to childhood absence epilepsy that occurs as brief staring episodes aming children in the age bracket of four and six. Once they age further, they usually outgrow this kind of seizures. Juvenile absence epilepsy starts a little later and continues into adulthood. Those suffering from absence seizures may also develop tonic-clonic seizures alongside.
• Myclonic seizures: These are characterised by sudden body or limb jerks involving the arms, head and neck. The spasms affect both sides of the body and occurs in the morning. When these seizures are seen during adolescence alongwith tonic-clonic seizures, they become a part of juvenile myoclonic epilepsy.
• Tonic and Atonic seizures, also known as drop attacks: Those with multiple brain injuries and intellectual disability may face sudden stiffness in the arms and body resulting in falls and injuries. These are known as tonic seizures and most of them who suffer from such seizures have a syndrome called Lennox Gastaut syndrome. People suffering from diffuse brain disorders may have stonic seizures which are characterised by sudden loss of bone tone resulting in collapsing and injuries. When seizures occur in sequence – first a brief tonic episode followed by atonic episode, it is called tonic-atonic seizure.
• Tonic, Clonic and Tonic-Clonic seizures, earlier known as Grand Mal seizures: These seizures can evolve from both focal and generalised seizure types. When a focal seizure spreads to both sides of the brain and cause tonic clonic seizures. Also, a group of myoclonic seizures can evolve into tonic clonic seizures. This kind of seizures can be a part of the juvenile Myoclonic Epilepsy.

Why is it important to classify and characterise seizures

Identifying the various kinds and characteristics of seizures is crucial for various reasons.

• Correct classification and characterisation paves way for appropriate treatment. Identifying it correctly makes the therapy and medications more accurate.
• Incorrect classification of seizures may actually lead to inappropriate medication that can worsen the condition.
• Classifying seizures into syndromes may give doctors better and in-depth information that may help in choosing the right treatment approach.

Correct classification and characterisation of seizures plays a significant role in accurate diagnosis and treatment of the condition leading to quick recovery.