Epilepsy is a group of neurological disorders characterized by recurrent epileptic seizures. Epileptic
seizures are episodes that can vary from brief and nearly undetectable periods to long periods of vigorous shaking. These episodes can result in physical injuries, including occasionally broken bones. In epilepsy,
seizures have a tendency to recur and, as a rule, have no immediate underlying cause. Isolated
seizures that are provoked by a specific cause such as poisoning are not deemed to represent epilepsy. People with
epilepsy may be treated differently in various areas of the world and experience varying degrees of social stigma due to their condition. The underlying mechanism of epileptic
seizures is excessive and abnormal neuronal activity in the cortex of the brain. The reason this occurs in most cases of
epilepsy is unknown. Some cases occur as the result of
brain injury, stroke,
brain tumors, infections of the brain, or
birth defects through a process known as epileptogenesis. Known genetic mutations are directly linked to a small proportion of cases. The diagnosis involves ruling out other conditions that might cause similar symptoms, such as fainting, and determining if another cause of
seizures is present, such as
alcohol withdrawal or electrolyte problems. This may be partly done by imaging the
brain and performing blood tests.
Epilepsy can often be confirmed with an electroencephalogram (EEG), but a normal test does not rule out the condition.
Epilepsy that occurs as a result of other issues may be preventable.
Seizures are controllable with medication in about 70% of cases; inexpensive anti-seizure medications are often available. In those whose
seizures do not respond to medication, surgery, neurostimulation or dietary changes may then be considered. Not all cases of
epilepsy are lifelong, and many people improve to the point that treatment is no longer needed. As of 2015, about 39 million people have epilepsy. Nearly 80% of cases occur in the developing world. In 2015, it resulted in 125,000 deaths, an increase from 112,000 in 1990.
Epilepsy is more common in older people. In the developed world, onset of new cases occurs most frequently in babies and the elderly. In the developing world, onset is more common in older children and young adults due to differences in the frequency of the underlying causes. About 5–10% of people will have an unprovoked
seizure by the age of 80, and the chance of experiencing a second
seizure is between 40 and 50%. In many areas of the world, those with
epilepsy either have restrictions placed on their ability to drive or are not permitted to drive until they are free of
seizures for a specific length of time. The word
epilepsy is from Ancient Greek seize, possess, or afflict. The most common type (60%) of
seizures are convulsive. Of these, one-third begin as generalized
seizures from the start, affecting both hemispheres of the brain. Two-thirds begin as focal
seizures (which affect one hemisphere of the brain) which may then progress to generalized seizures. The remaining 40% of
seizures are non-convulsive. An example of this type is the absence seizure, which presents as a decreased level of consciousness and usually lasts about 10 seconds. Focal
seizures are often preceded by certain experiences, known as auras. They include sensory (visual, hearing, or smell), psychic, autonomic, and motor phenomena. Jerking activity may start in a specific muscle group and spread to surrounding muscle groups in which case it is known as a Jacksonian march. Automatisms may occur, which are non-consciously-generated activities and mostly simple repetitive movements like smacking of the lips or more complex activities such as attempts to pick up something.
Relevant Topics in Medical Sciences
