Key Points
- Seizure disorder is defined as the presence of at least two unprovoked seizures.
- Temporal lobe seizures are the most common cause of seizure disorder.
- Seizure disorder is successfully medically managed in approximately 60% of patients; refractory seizures may be treated with resection of epileptogenic brain tissue or implantation of brain stimulators.
Introduction
- Seizure disorder, also known as epilepsy, is a neurologic disorder characterized by recurrent seizures that result from abnormal electrical brain activity.
- A diagnosis of seizure disorder can be made in a patient who experiences at least two unprovoked seizures.
- Seizures can present with motor symptoms, non-motor symptoms, or both. The nidus of seizure activity may originate in one hemisphere (focal) or both hemispheres (generalized) of the brain.
Epidemiology and Risk Factors
- Seizure disorder is one of the most common neurological diseases, with a national prevalence in the United States of around 1%.1
- The age of onset follows a bimodal distribution, with peak incidence in children and the elderly.2
- Seizure disorder is often comorbid with other central nervous system (CNS) pathologies, including memory loss, chronic pain, and stroke. Seizure disorder has also been found to be associated with chronic obstructive pulmonary disease (COPD); this link is suspected to be due to the hypercapnia associated with COPD.3
- The incidence of perioperative seizures in patients with epilepsy is approximately 2–3%. Studies have not found a link between the type of anesthesia or type of surgery and this risk.4
- In addition to seizure disorder, many genetic, metabolic, and structural diseases can also present with recurrent seizures, including:5
- Hypoglycemia, hypocalcemia, hypomagnesemia, and hypo- or hypernatremia
- Intracranial tumors or lesions
- Encephalitis or CNS inflammation
- Tuberous sclerosis or mitochondrial diseases
- Withdrawal from CNS depressants, including benzodiazepines or ethanol
Pathophysiology
- Seizures are caused by abnormal, synchronous depolarization of neurons in the cortex, resulting in motor symptoms, sensory symptoms, or both.6
- The current terminology for seizures (2017 International League Against Epilepsy classification) divides them into focal seizures and generalized seizures:
- Focal seizures originate in only one hemisphere of the brain but may spread to both hemispheres.
- Focal motor seizures typically involve involuntary jerking or flexing movements of one or more limbs or facial muscle groups.
- Focal non-motor seizures include unusual sensations, emotions, or hallucinations.
- Focal seizures may also be characterized by the patient’s level of consciousness during the seizures.
- Focal aware seizures (previously called simple partial seizures): the patient maintains consciousness (awake and alert) and will remember the seizure afterwards.
- Focal impaired awareness seizures (previously called complex partial seizures): the level of consciousness and/or alertness is impaired.
- A special case is focal to bilateral tonic-clonic seizures, which originate in one hemisphere but rapidly spread to the contralateral hemisphere, resulting in body-wide convulsions.
- Generalized seizures originate in both cerebral hemispheres simultaneously.
- Generalized seizures almost always present with impaired awareness, often with a complete loss of consciousness.
- Generalized motor seizures include tonic-clonic and myoclonic-tonic-clonic seizures, characterized by full-body convulsions and jerking movements, respectively.
- Generalized non-motor seizures, also known as absence seizures, involve a brief interruption in consciousness and awareness, or “blanking out”.
- Temporal lobe seizures are the most common cause of seizure disorder, with focal impaired awareness seizures being the most common manifestation.7
- The predisposition to seizures in patients with seizure disorder is thought to result from an interplay between abnormal synaptic connections, altered neurotransmitter levels, abnormal ion channel function, and/or structural insults to the brain.8
Treatment Options
- In approximately 60% of patients, seizure disorder is well managed by antiepileptic drugs (AEDs) 9, though these medications are susceptible to variations in bioavailability and serum concentration.10
- For patients with recurrent seizures despite appropriate uptitration of multiple AEDs, treatment options include resection of epileptogenic brain tissue (to preserve normal CNS function) or implantation of brain-stimulating devices.9
- Brain-stimulating technology includes:11
- Deep brain stimulation: stimulating leads are placed in locations of the brain from which epileptiform activity originates.
- Responsive neurostimulation: uses an electroencephalogram to sense the beginning of seizure activity and stimulate the brain to desynchronize epileptiform activity.
- Vagus nerve stimulation: thought to modulate thalamocortical circuits by stimulating the vagus nerve.
References
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- Zhou Y, Kobau R, Pastula DM, Greenlund KJ. Comorbidity Among Adults With Epilepsy - United States, 2021-2022. Prev Chronic Dis. 2024;21:E100. Published 2024 Dec 19. PubMed
- Niesen AD, Jacob AK, Aho LE, et al. Perioperative seizures in patients with a history of a seizure disorder. Anesth Analg. 2010;111(3):729-735. PubMed
- Lovik K, Murr NI. Seizure. In: StatPearls (Internet). Treasure Island, FL. StatPearls Publishing; 2025. Accessed 2025-11-14. PubMed
- McWilliam M, Asuncion RMD, Al Khalili Y. Idiopathic (Genetic) Generalized Epilepsy. In: StatPearls (Internet). Treasure Island, FL. StatPearls Publishing; 2025. Accessed 2025-11-14. PubMed
- McIntosh WC, Das JM. Temporal Seizure. In: StatPearls (Internet). Treasure Island, FL. StatPearls Publishing; 2025. Accessed 2025-11-16. PubMed
- Stafstrom CE, Carmant L. Seizures and epilepsy: an overview for neuroscientists. Cold Spring Harb Perspect Med. 2015;5(6):a022426. Published 2015 Jun 1. PubMed
- Chen Z, Brodie MJ, Liew D, Kwan P. Treatment Outcomes in Patients With Newly Diagnosed Epilepsy Treated With Established and New Antiepileptic Drugs: A 30-Year Longitudinal Cohort Study. JAMA Neurol. 2018;75(3):279-286. PubMed
- Johannessen SI, Landmark CJ. Antiepileptic drug interactions - principles and clinical implications. Curr Neuropharmacol. 2010;8(3):254-267. PubMed
- Gouveia FV, Warsi NM, Suresh H, Matin R, Ibrahim GM. Neurostimulation treatments for epilepsy: Deep brain stimulation, responsive neurostimulation and vagus nerve stimulation. Neurotherapeutics. 2024;21(3):e00308. PubMed
Other References
- Henthorn PK, Carrico JA. Hepatic drug metabolism and Cytochrome P450. OA summary. 2023. Link
- Jonik B, Saka E. Status epilepticus. OA summary 2025. Link
- Momjian MP, Akano A. Seizure disorder: Perioperative considerations. OA summary. 2025 Link
- Hopkinson H, Chatterjee D. Intraoperative seizures. OA summary. 2025. Link
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