Editing Epilepsy (section)

==Diagnosis==
The diagnosis of epilepsy is primarily clinical, based on a thorough evaluation of the person’s history, seizure features, and risk of recurrence. While diagnostic tests such as [[electroencephalogram]]s and [[neuroimaging]] can support the diagnosis, there is no single test that can confirm or exclude epilepsy.

Clinicians must also distinguish epileptic seizures from other conditions that can mimic them and determine whether the event was provoked by an acute, reversible cause or if it suggests a long-term tendency for unprovoked seizures.

===Definition===
According to the [[International League Against Epilepsy]] (ILAE), a diagnosis of epilepsy can be made when any one of the following criteria is met:<ref name=Fisher2014/>
:{| cellpadding=5 style="border:1px solid #ccc"
|- bgcolor="#fafafa"
|
# At least two unprovoked (or reflex) seizures occurring more than 24 hours apart
# One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years
# Diagnosis of an epilepsy syndrome
|}

The ILAE also introduced the concept of resolved epilepsy, which applies to individuals who are past the typical age range for an age-dependent syndrome, or who have remained seizure-free for at least 10 years, including the last 5 years without medication.<ref name="Fisher2014" />

This 2014 practical definition built upon the broader 2005 conceptual framework, which defined epilepsy as a disorder involving an enduring predisposition to generate epileptic seizures. The updated criteria incorporated recurrence risk and reflected the realities of clinical decision-making. While widely adopted in clinical settings, other definitions—such as the traditional “two unprovoked seizures” rule still used by the [[World Health Organization]] — remain appropriate in epidemiology and public health contexts, provided they are clearly stated. The 2014 revision also shifted terminology, referring to epilepsy as a ''disease'' rather than a disorder, to reflect its medical seriousness and public health impact.<ref name="Pana2011">{{cite journal |vauthors=Panayiotopoulos CP |date=December 2011 |title=The new ILAE report on terminology and concepts for organization of epileptic seizures: a clinician's critical view and contribution |journal=Epilepsia |volume=52 |issue=12 |pages=2155–2160 |doi=10.1111/j.1528-1167.2011.03288.x |pmid=22004554 |doi-access=free}}</ref><ref name="Fisher2014" />

===Classification===
[[File:ILAE classification of seizure types 2017.png|thumb|Revised operational scheme of seizure classification, ILAE, 2017]]
Once epilepsy is diagnosed, the [[International League Against Epilepsy|ILAE]] recommends a three-level framework to guide further classification and management:<ref name="Scheffer2017" />

* Identify the seizure type, based on clinical features and EEG (e.g., focal aware seizure, generalized absence)
* Determine the epilepsy type, such as focal, generalized, combined, or unknown
* Identify an epilepsy syndrome, if applicable

Not all levels can always be determined; in some cases, only the seizure type is identifiable. The etiology — whether structural, genetic, infectious, metabolic, immune, or unknown — should be considered at each stage of classification, as it often influences treatment and prognosis.<ref name="2011rec">{{cite journal |vauthors=Shorvon SD |date=June 2011 |title=The etiologic classification of epilepsy |journal=Epilepsia |volume=52 |issue=6 |pages=1052–1057 |doi=10.1111/j.1528-1167.2011.03041.x |pmid=21449936 |doi-access=free}}</ref><ref name="Scheffer2017" />

The classification of epilepsies has evolved significantly over time.<ref name="ILEA1989">{{cite journal |vauthors= |year=1989 |title=Proposal for revised classification of epilepsies and epileptic syndromes. Commission on Classification and Terminology of the International League Against Epilepsy |journal=Epilepsia |volume=30 |issue=4 |pages=389–399 |doi=10.1111/j.1528-1157.1989.tb05316.x |pmid=2502382}}</ref> Earlier systems emphasized seizure location and used terms such as “partial” or “cryptogenic,” which have been replaced in the modern framework.<ref>{{cite journal |vauthors=Engel J |date=August 2006 |title=ILAE classification of epilepsy syndromes |journal=Epilepsy Research |volume=70 |issue=Suppl 1 |pages=S5-10 |doi=10.1016/j.eplepsyres.2005.11.014 |pmid=16822650}}</ref><ref>{{cite journal |vauthors=Berg AT, Berkovic SF, Brodie MJ, Buchhalter J, Cross JH, van Emde Boas W, Engel J, French J, Glauser TA, Mathern GW, Moshé SL, Nordli D, Plouin P, Scheffer IE |date=April 2010 |title=Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005-2009 |journal=Epilepsia |volume=51 |issue=4 |pages=676–685 |doi=10.1111/j.1528-1167.2010.02522.x |pmid=20196795 |doi-access=free}}</ref> The current system, introduced in 2017, reflects advances in neuroimaging, genetics, and clinical understanding, and allows for a more individualized and dynamic diagnostic approach.

===Syndromes===
{{Main|Epilepsy syndromes}}
An [[Epilepsy syndromes|epilepsy syndrome]] is a specific diagnosis based on a combination of features, including seizure types, age of onset, EEG patterns, imaging findings, and associated symptoms or comorbidities. In many cases, a known genetic or structural cause may also support the diagnosis. Recognizing a syndrome can guide treatment decisions, inform prognosis, and provide clarity for individuals and families navigating an epilepsy diagnosis.<ref name="ileasyndromes2014">{{cite web |title=Epilepsy syndromes |url=https://www.epilepsydiagnosis.org/syndrome/epilepsy-syndrome-groupoverview.html |url-status=live |archive-url=https://web.archive.org/web/20141006173716/https://www.epilepsydiagnosis.org/syndrome/epilepsy-syndrome-groupoverview.html |archive-date=6 October 2014 |access-date=6 October 2014 |publisher=International league against epilepsy}}</ref><ref>{{Cite journal |last1=Wirrell |first1=Elaine C. |last2=Nabbout |first2=Rima |last3=Scheffer |first3=Ingrid E. |last4=Alsaadi |first4=Taoufik |last5=Bogacz |first5=Alicia |last6=French |first6=Jacqueline A. |last7=Hirsch |first7=Edouard |last8=Jain |first8=Satish |last9=Kaneko |first9=Sunao |last10=Riney |first10=Kate |last11=Samia |first11=Pauline |last12=Snead |first12=O. Carter |last13=Somerville |first13=Ernest |last14=Specchio |first14=Nicola |last15=Trinka |first15=Eugen |date=2022 |title=Methodology for classification and definition of epilepsy syndromes with list of syndromes: Report of the ILAE Task Force on Nosology and Definitions |url=https://onlinelibrary.wiley.com/doi/10.1111/epi.17237 |journal=Epilepsia |language=en |volume=63 |issue=6 |pages=1333–1348 |doi=10.1111/epi.17237 |issn=1528-1167}}</ref>

Some syndromes are self-limited and age-dependent, such as [[childhood absence epilepsy]], [[juvenile myoclonic epilepsy]], and self-limited epilepsy with centrotemporal spikes.<ref name="Nel2012" /> These typically respond well to treatment or remit with age. In contrast, more severe syndromes fall under the category of developmental and epileptic encephalopathies (DEEs).<ref>{{Cite journal |last1=Raga |first1=Sharika |last2=Specchio |first2=Nicola |last3=Rheims |first3=Sylvain |last4=Wilmshurst |first4=Jo M. |date=2021-02-01 |title=Developmental and epileptic encephalopathies: recognition and approaches to care |url=https://pubmed.ncbi.nlm.nih.gov/33632673 |journal=Epileptic Disorders: International Epilepsy Journal with Videotape |volume=23 |issue=1 |pages=40–52 |doi=10.1684/epd.2021.1244 |issn=1950-6945 |pmid=33632673|doi-access=free }}</ref> These include [[Lennox–Gastaut syndrome]], [[West syndrome]], and [[Dravet syndrome]], which are associated with early onset, drug-resistant seizures, and significant neurodevelopmental impairments.<ref name="jcnnordli2012">{{cite journal |vauthors=Nordli DR |date=October 2012 |title=Epileptic encephalopathies in infants and children |journal=Journal of Clinical Neurophysiology |volume=29 |issue=5 |pages=420–424 |doi=10.1097/WNP.0b013e31826bd961 |pmid=23027099}}</ref>

Some epilepsy syndromes do not yet fit neatly within current etiological categories, particularly when no definitive cause has been identified. In many cases, a genetic cause is presumed based on age of onset, family history, and electroclinical features, even if no mutation has been found. As genetic and neuroimaging technologies continue to evolve, the classification of epilepsy syndromes is expected to become more precise.<ref name="2011rec" />

===Tests===
<!--EEG Same as seizure  -->
[[File:EEG Recording Cap.jpg|thumb|upright=1.4|An [[electroencephalography|EEG]] can aid in locating the focus of the epileptic seizure.l]]The diagnostic evaluation of epilepsy begins with confirming whether the reported event was in fact a seizure. A detailed clinical history remains essential, supported by eyewitness accounts and, when possible, video recordings. The initial assessment aims to distinguish epileptic seizures from common mimics such as [[Syncope (medicine)|syncope]], [[psychogenic non-epileptic seizures]], or transient ischemic attacks.

Following clinical evaluation, selected tests may be used to rule out acute causes and seizure mimics. A 12-lead [[Electrocardiography|electrocardiogram]] (ECG) is recommended for all individuals presenting with a first seizure, to screen for [[cardiac arrhythmias]] and other cardiovascular conditions that may resemble epilepsy. Blood tests may be performed to identify metabolic disturbances such as [[hypoglycemia]], [[Electrolyte imbalance|electrolyte imbalances]], or renal and hepatic dysfunction, particularly in acute settings.<ref name="NICE2022">{{Cite book |url=https://www.ncbi.nlm.nih.gov/books/NBK581165/ |title=Epilepsies in children, young people and adults |date=2022 |publisher=National Institute for Health and Care Excellence (NICE) |isbn=978-1-4731-4513-9 |series=National Institute for Health and Care Excellence: Guidelines |location=London |pmid=35700280}}</ref>

Once epilepsy is suspected, [[electroencephalography]] (EEG) is used to support the diagnosis, classify seizure types, and help identify specific epilepsy syndromes. A routine EEG may include activation techniques such as [[hyperventilation]] or photic stimulation. However, a normal EEG does not rule out epilepsy. When initial EEG findings are inconclusive, further studies such as sleep-deprived EEG, ambulatory EEG, or long-term video EEG monitoring may be considered.<ref name="NICE2022" />

Neuroimaging, usually with [[magnetic resonance imaging]] (MRI), is recommended to detect structural causes of epilepsy. If MRI is contraindicated or unavailable, [[computed tomography]] (CT) may be considered. Imaging should be interpreted by radiologists with expertise in epilepsy.<ref name="NICE2022" />

Additional tests may be guided by clinical context. [[Genetic testing]] may be considered in individuals with early-onset epilepsy, developmental delay, or features of a known genetic epilepsy syndrome. Testing for neuronal antibodies may be appropriate in suspected cases of [[autoimmune encephalitis]], particularly when seizures are new-onset, rapidly progressive, or resistant to standard treatment. Metabolic testing may be pursued in infants or children with unexplained epilepsy, especially when developmental regression or multisystem involvement is present.<ref name="NICE2022" />

Serum [[prolactin]] may occasionally be measured after a suspected seizure, particularly to help distinguish epileptic seizures from non-epileptic events. While it can be elevated following certain seizure types, the test lacks sufficient sensitivity and specificity and is not recommended for routine use.

===Differential diagnosis===
A number of conditions can resemble epileptic seizures, leading to potential misdiagnosis. Accurate diagnosis is essential, as inappropriate treatment may delay effective care or cause harm. Common mimics include [[Syncope (medicine)|fainting]] (syncope), [[psychogenic non-epileptic seizures]] (PNES), [[Transient ischemic attack|transient ischemic attacks]], [[migraine]], [[narcolepsy]], and various sleep or movement disorders.<ref>{{cite journal |vauthors=Brodtkorb E |year=2013 |title=Common imitators of epilepsy |journal=Acta Neurologica Scandinavica. Supplementum |volume=127 |issue=196 |pages=5–10 |doi=10.1111/ane.12043 |pmid=23190285 |doi-access=free}}</ref><ref name="Rosen2010">{{cite book |url=https://books.google.com/books?id=u7TNcpCeqx8C&pg=PA2228 |title=Rosen's emergency medicine: concepts and clinical practice |publisher=Mosby/Elsevier |year=2010 |isbn=978-0-323-05472-0 |veditors=Marx JA |edition=7th |location=Philadelphia |page=2228}}</ref> In children, [[Gastroesophageal reflux disease|reflux]], breath-holding spells, and parasomnias such as night terrors may also resemble seizures.<ref name="Rosen2010" />

Psychogenic non-epileptic seizures (PNES) are a particularly important consideration, especially in individuals with refractory epilepsy. PNES are involuntary episodes that resemble epileptic seizures but are not associated with abnormal electrical discharges. They are classified as functional neurological disorders and are typically associated with psychological distress or trauma. Studies suggest that approximately 20% of individuals referred to epilepsy centers are diagnosed with PNES,<ref name="AFP2012" /> and up to 10% of these individuals also have coexisting epilepsy.<ref name="Jer2013">{{cite book |url=https://books.google.com/books?id=5PgjmjugIX8C&pg=PA462 |title=Seizures and epilepsy |vauthors=Jerome E |publisher=Oxford University Press |year=2013 |isbn=978-0-19-532854-7 |edition=2nd |location=New York |page=462}}</ref> Differentiating between the two can be difficult and often requires prolonged video EEG monitoring.<ref name="Jer2013" />

Misdiagnosis remains a significant concern in epilepsy. Reported rates vary widely — from 2% to 71% — depending on factors such as clinical setting, patient population, diagnostic criteria, and physician expertise.<ref>{{Cite journal |last=Oto |first=Maria (Meritxell) |date=2017-01-01 |title=The misdiagnosis of epilepsy: Appraising risks and managing uncertainty |url=https://www.sciencedirect.com/science/article/pii/S1059131116302977 |journal=Seizure |series=25th Anniversary Issue |volume=44 |pages=143–146 |doi=10.1016/j.seizure.2016.11.029 |issn=1059-1311}}</ref><ref>{{Cite journal |last=Xu |first=Ying |last2=Nguyen |first2=Dennis |last3=Mohamed |first3=Armin |last4=Carcel |first4=Cheryl |last5=Li |first5=Qiang |last6=Kutlubaev |first6=Mansur A. |last7=Anderson |first7=Craig S. |last8=Hackett |first8=Maree L. |date=2016-10-01 |title=Frequency of a false positive diagnosis of epilepsy: A systematic review of observational studies |url=https://www.seizure-journal.com/article/S1059-1311(16)30133-9/fulltext |journal=Seizure - European Journal of Epilepsy |language=English |volume=41 |pages=167–174 |doi=10.1016/j.seizure.2016.08.005 |issn=1059-1311 |pmid=27592470}}</ref> While epilepsy can be mistakenly diagnosed in individuals with other conditions, the opposite can also occur: certain forms of epilepsy, particularly those with subtle or nocturnal symptoms,<ref>{{Cite journal |last=Miano |first=Silvia |last2=Peraita-Adrados |first2=Rosa |date=2013-03-01 |title=[Nocturnal frontal lobe epilepsy is often misdiagnosed as sleep disorders in children: a case series] |url=https://pubmed.ncbi.nlm.nih.gov/23440753 |journal=Revista De Neurologia |volume=56 |issue=5 |pages=257–267 |issn=1576-6578 |pmid=23440753}}</ref> may be mistaken for behavioral or psychological disorders. Delays in diagnosis can lead to prolonged morbidity and inappropriate treatment, highlighting the importance of careful clinical assessment and appropriate use of EEG and video documentation.