What is a seizure? 

A seizure is a sudden, uncontrolled electrical disturbance in the brain. It happens when nerve cells, or neurons, send excessive or synchronized electrical signals all at once, disrupting the normal communication pathways of the central nervous system. This surge of electrical activity can cause temporary changes in behavior, movements, feelings, and levels of consciousness. While many people associate seizures with visible shaking or convulsions, they can also manifest as subtle symptoms like staring spells, unusual sensations, or a brief loss of awareness. 

In a clinical setting, it is important to distinguish between a single seizure and epilepsy. A seizure is a single event, whereas epilepsy is a chronic neurological condition characterized by a tendency to have recurrent, unprovoked seizures. Seizures can be triggered by many factors, including high fever, head trauma, low blood sugar, or drug withdrawal. Understanding the specific type of seizure an individual is experiencing is essential for medical professionals to determine the underlying cause and provide the most effective treatment plan to maintain neurological stability. 

What we will discuss in this article 

• The physiological mechanism of electrical bursts in the brain 

• Different categories of seizures and how they present 

• Common triggers and underlying causes of seizure activity 

• The difference between provoked and unprovoked seizures 

• Diagnostic tools used by doctors to assess seizure activity 

• Immediate first aid and safety steps for bystanders 

• Emergency guidance for identifying when to seek urgent care 

How a seizure happens in the brain 

The brain operates using a delicate balance of electrical impulses that allow us to think, move, and feel. 

The electrical surge 

During a seizure, this balance is lost. A group of neurons becomes hyper excitable and fires signals in an abnormal, rapid, and disorganized way. This electrical storm can remain localized in one small part of the brain or spread to involve both hemispheres. The symptoms a person experiences are a direct reflection of which part of the brain is being affected. If the electrical activity reaches the motor cortex, the person will experience muscle jerks; if it involves the temporal lobe, they might experience strange smells or sudden emotional shifts. 

Types of seizures 

Seizures are classified based on where the electrical activity begins and whether consciousness is affected. 

Focal onset seizures 

Focal seizures start in one specific area of the brain. They are divided into focal aware seizures, where the person remains conscious and knows what is happening, and focal impaired awareness seizures, where the person appears confused or performs repetitive, purposeless movements like lip smacking. These were formerly known as partial seizures. 

Generalised onset seizures 

Generalised seizures involve both sides of the brain from the start. These include absence seizures, which look like brief staring spells, and tonic clonic seizures, which involve a loss of consciousness and full body convulsions. Other types include atonic seizures, where the person suddenly loses muscle tone and may fall, and myoclonic seizures, which cause brief, shock like jerks of a muscle or group of muscles. 

Comparison: Focal vs Generalised Seizures 

Feature	Focal Seizures	Generalised Seizures
Starting Point	One specific part of the brain	Both sides of the brain
Awareness	Can be fully preserved or impaired	Usually lost immediately
Typical Signs	Unusual tastes, smells, or jerks	Convulsions or staring spells
Memory	The person may remember the event	Usually no memory of the event
Duration	Often lasts 1 to 2 minutes	Can range from seconds to minutes

Causes and triggers of seizures 

Not every seizure is caused by epilepsy; many are provoked by temporary external or internal factors. 

• Medical Conditions: High fever common in children, infections like meningitis, or a sudden stroke can trigger a seizure. 

• Metabolic Imbalances: Very low blood sugar, sodium imbalances, or kidney and liver failure can disrupt brain chemistry. 

• Trauma: A significant head injury or brain tumor can create scar tissue that interferes with electrical signals. 

• Lifestyle Factors: Extreme sleep deprivation, high stress, or the sudden withdrawal from alcohol or certain medications can lower the seizure threshold. 

• Genetic Predisposition: Some individuals are born with a lower threshold for seizure activity due to their genetic makeup. 

To Summarise 

A seizure is a temporary disruption of the brain electrical activity that can affect anyone under the right circumstances. While the experience can be intense and frightening for both the person and those watching, most seizures are brief and end on their own without causing permanent damage. Identifying whether a seizure was a one off event caused by a specific trigger or part of a long term condition like epilepsy is the primary goal of a medical evaluation. With proper diagnosis and management, most people who experience seizures can live healthy, active lives while minimizing the risk of future events. 

Emergency guidance 

If you see someone having a seizure, stay calm and track the time. Clear the area of hard or sharp objects to prevent injury. Do not restrain the person or put anything in their mouth, as this can cause choking or injury. Place something soft under their head and loosen tight clothing around their neck. Once the seizure ends, turn them onto their side in the recovery position. Call 999 if the seizure lasts longer than five minutes, if the person does not wake up afterward, if they are pregnant or injured, or if you know it is their first seizure. 

Authority Snapshot 

Dr. Rebecca Fernandez is a physician with an MBBS and experience in general surgery, cardiology, internal medicine, gynecology, intensive care, and emergency medicine. She has managed critically ill patients, stabilised acute trauma cases, and provided comprehensive inpatient and outpatient care. In psychiatry, Dr. Fernandez has worked with psychotic, mood, anxiety, and substance use disorders, applying evidence based approaches such as CBT, ACT, and mindfulness based therapies. Her skills span patient assessment, treatment planning, and the integration of digital health solutions to support mental well being in 2026.