Definition and Diagnosis
Epilepsy is a chronic neurological condition defined by a lasting predisposition to generate epileptic seizures, typically diagnosed after at least two unprovoked seizures occurring more than 24 hours apart, or one unprovoked seizure with a high probability of recurrence.
Epidemiology
Epilepsy affects a substantial number of people worldwide, with the highest incidence in early childhood and again in older adulthood. Prevalence is higher in low- and middle-income countries, partly reflecting differences in perinatal care, infection rates, and access to treatment.
Risk Factors
Risk factors include perinatal brain injury, traumatic brain injury, stroke, central nervous system infections, brain tumors, genetic and developmental conditions, and a family history of epilepsy. In many cases, particularly in adults with new-onset seizures, an underlying structural or metabolic cause is identified.
Symptoms and Subtypes
Presentation depends on seizure type, ranging from brief lapses in awareness (absence seizures) to focal seizures with retained or impaired awareness, to generalized tonic-clonic seizures with convulsions and loss of consciousness. A post-ictal period of confusion, fatigue, or headache commonly follows larger seizures.
Diagnosis
Diagnosis relies on a detailed clinical history from the patient and witnesses, electroencephalography (EEG) to identify epileptiform activity, and neuroimaging (typically MRI) to identify structural causes. Video-EEG monitoring may be used in complex or diagnostically uncertain cases.
Treatment
Treatment is primarily with antiseizure medications selected according to seizure type, with many patients achieving good seizure control on monotherapy. For medication-resistant epilepsy, options include epilepsy surgery, vagus nerve stimulation, dietary therapy such as the ketogenic diet, and other neuromodulation approaches.
Prognosis
A majority of people with epilepsy achieve good seizure control with appropriate medication, and many eventually enter long-term remission. A minority develop drug-resistant epilepsy requiring specialized management, and ongoing risks include injury during seizures and, rarely, sudden unexpected death in epilepsy (SUDEP).
Reference
Sadock, B. J., Sadock, V. A., & Ruiz, P. Kaplan & Sadock's Synopsis of Psychiatry (11th ed.).