Epilepsy

Epilepsy is a complex group of neurological disorders. It is defined by a tendency to experience recurrent, unprovoked seizures. A seizure is a sudden burst of abnormal electrical activity in the brain.

These electrical bursts can cause many different symptoms. Some people experience brief lapses in awareness or simple muscle jerks. Others may undergo prolonged convulsions. These episodes can lead to physical injuries like broken bones. They can also cause accidents through loss of control. A diagnosis of epilepsy usually requires at least two unprovoked seizures. These seizures must occur more than 24 hours apart. In some cases, one seizure is enough for a diagnosis if the risk of recurrence is high.

Seizures function through different electrical pathways in the brain. The International League Against Epilepsy (ILAE) classifies them into four main groups. Focal seizures originate in one specific area of the brain. These may involve localized networks or spread to nearby regions. A person might experience a focal seizure with preserved consciousness. This means they remain aware and responsive during the event. Some focal seizures involve impaired consciousness, where awareness is lost. These may be preceded by an aura, which is a warning sensation.

Focal seizures can also include sensory, psychic, or motor phenomena. For example, a Jacksonian march occurs when muscle jerks spread to surrounding groups.

Generalized seizures follow a different mechanism of action. These seizures originate at a specific point but spread quickly across both hemispheres. This spread happens through interconnected brain networks. Most generalized seizures impair consciousness from the very beginning. One common type is the generalized tonic-clonic seizure. This involves a tonic phase of stiffening followed by a clonic phase of rhythmic jerking.

Another type is the absence seizure, which causes brief lapses in awareness. These may involve eye blinking or subtle head turning. Other types include myoclonic seizures, which cause brief muscle jerks. Atonic seizures involve a sudden loss of muscle tone, often causing falls.

Many different factors can cause these electrical disruptions. The ILAE classifies causes into six broad categories. These include structural, genetic, infectious, metabolic, immune, and unknown causes. Structural causes involve physical abnormalities in the brain anatomy. These can be acquired from strokes, brain tumors, or traumatic brain injuries. They can also be developmental or genetic in origin. For instance, mesial temporal sclerosis is a common structural cause. Genetic conditions are more frequent in children. Conversely, strokes and tumors are more common in older adults. In approximately 50% of cases, no clear cause is identified.

History shows that humans have studied these patterns for centuries. The word epilepsy comes from Ancient Greek. It means "to seize, possess, or afflict."

Early thinkers like Hippocrates documented these conditions long ago. Today, doctors use advanced tools to understand the brain. They use neuroimaging and blood tests to rule out other conditions. Electroencephalography, or EEG, is a vital tool.

An EEG records the electrical activity of the brain. This helps doctors see the patterns of the seizures. This scientific approach allows for much more precise diagnoses than in the past.

Epilepsy has a massive global impact. Approximately 50 million people worldwide live with the condition. Nearly 80% of these cases occur in low- and middle-income countries. The burden in low-income countries is more than twice that of high-income countries. This is likely due to higher exposure to risks like infections and brain injuries. It is also due to limited access to healthcare. In 2021, epilepsy was responsible for an estimated 140,000 deaths. This is an increase from 125,000 deaths in 1990. About 5% to 10% of people will have an unprovoked seizure by age 80.

Managing epilepsy involves various medical and social considerations. About 69% of cases can be controlled with anti-seizure medications.

These medications are often inexpensive and widely available. If drugs do not work, doctors may suggest surgery or neurostimulation. Dietary changes are another option for some patients. People may also wear medical alert bracelets for safety.

Living with epilepsy can also affect mental health. About one-in-three people with epilepsy have a history of a psychiatric disorder. This includes conditions like depression, anxiety, and ADHD. These challenges can lead to social stigma or functional disability. However, many people improve so much that they no longer need treatment.