EPILEPSY

Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or synchronous neuronal activity in the brain.[3] About 50 million people worldwide have epilepsy, with almost 90% of these people being in developing countries.[4]Epilepsy is more likely to occur in young children, or people over the age of 65 years, however it can occur at any time.[5] As a consequence of brain surgery epileptic seizures may occur in recovering patients.
Epilepsy is usually controlled, but cannot be cured with medication, althoughsurgery may be considered in difficult cases. However, over 30% of people with epilepsy do not have seizure control even with the best available medications.[6][7]Not all epilepsy syndromes are lifelong – some forms are confined to particular stages of childhood. Epilepsy should not be understood as a single disorder, but rather as syndromic with vastly divergent symptoms but all involving episodic abnormal electrical activity in the brain.

The diagnosis of epilepsy usually requires that the seizures occur spontaneously. Nevertheless, certain epilepsy syndromes require particular precipitants or triggers for seizures to occur. These are termed reflex epilepsy. For example, patients withprimary reading epilepsy have seizures triggered by reading. Photosensitive epilepsy can be limited to seizures triggered by flashing lights. Other precipitants can trigger an epileptic seizure in patients who otherwise would be susceptible to spontaneous seizures. For example, children with childhood absence epilepsy may be susceptible to hyperventilation. In fact, flashing lights and hyperventilation are activating procedures used in clinical EEG to help trigger seizures to aid diagnosis. Finally, other precipitants can facilitate, rather than obligately trigger, seizures in susceptible individuals. Emotional stress, sleep deprivation, sleep itself, heat stress, alcohol and febrile illness are examples of precipitants cited by patients with epilepsy. Notably, the influence of various precipitants varies with the epilepsy syndrome.[20]. Likewise, the menstrual cycle in women with epilepsy can influence patterns of seizure recurrence. Catamenial epilepsy is the term denoting seizures linked to the menstrual cycle.[21]

There are different causes of epilepsy that are common in certain age groups.

During the neonatal period and early infancy the most common causes include hypoxic-ischemic encephalopathies, CNS infections,trauma,congenital CNS abnormalities and metabolic disorders.
During late infancy and early childhood, febrile seizures are very common.There may be other causes like CNS infections and trauma.
During childhood well defined epilepsy syndromes are generally seen.
During adolescence and adulthood,the causes are more likely to be secondary to any CNS lesion and idiopathic epilepsies are less commmon. Other causes associated with these age groups are trauma,CNS infections,brain tumours,illicit drug use and alcohol withdrawal.
In older adults, cerebrovascular disease is a very common cause. other causes are CNS tumours, trauma and other degenerative diseases that are common to the older age group like alzheimers

Epilepsy can be triggered by brain damage caused by other disorders.

Epilepsy can sometimes be stopped by treating these underlying disorders. In other cases, epileptic seizures will continue after the underlying cause is treated.

Whether the seizures can be stopped depends on the type of disorder, the part of the brain that is affected, and how much damage has been done. Disorders that may trigger epilepsy include:

Brain tumors, alcoholism, and Alzheimer’s disease can cause epilepsy because they alter the normal workings of the brain.
Stroke, heart attacks, and other conditions that affect the blood supply to the brain (cerebrovascular diseases) can cause epilepsy by depriving the brain of oxygen. About a third of all new cases of epilepsy that develop in older people are caused by cerebrovascular diseases.
Infectious diseases such as meningitis, viral encephalitis, and AIDS, can cause epilepsy.
Cerebral palsy, autism, and a number of other developmental and metabolic disorders can cause epilepsy.

Head Injury

Head injuries can cause seizures. If the head injury is severe, the seizures may not begin until years later. If the injury is mild, the risk is slight.

Prenatal Injuries

In a fetus, the developing brain is susceptible to prenatal injuries that may occur if the pregnant mother has an infection, doesn’t eat properly, smokes or abuses drugs or alcohol. These conditions may cause cerebral palsy.

About 20% of seizures in children are caused by cerebral palsy or other nervous system diseases. Sometimes epilepsy is linked to areas in the brain where neurons may not have formed properly during prenatal development.

Environmental Causes

Epilepsy can be caused by:

Environmental and occupational exposure to lead, carbon monoxide, and certain chemicals
Use of street drugs and alcohol
Lack of sleep, stress, or hormonal changes
Withdrawal from certain antidepressant and anti-anxiety drugs