####Epidemiology Epilepsy is the most common serious neurological condition in the UK, affecting 1:140 of the population, according to Epilepsy Action. It has a bimodal incidence, more commonly presenting in children and above the age of 60 years, but can present at any age. Men and women are affected equally. About 60-80% of patients with epilepsy will have seizures completely controlled by anti-epileptic drugs (AED), but a minority will have drug resistant epilepsy. ####Definitions #####Seizures A seizure is 'the clinical manifestation of synchronised discharges from a set of cortical neurones'. Seizures may involve the whole brain (generalised), or part of the brain (focal). Although other rare seizure types are observed, only common types are described here. #####*Generalised* * Tonic clonic: patient loses consciousness, with initially a tonic phase (axial rigidity, neck and limb extension), followed by a clonic phase (rhythmic jerking of arms and/or legs). Apnoea and cyanosis are common but not essential features. The seizure commonly lasts up to five minutes (usually shorter), followed by confusion (the 'post-ictal' period), which may be accompanied by vomiting and/or headache, reduced level of consciousness or (rarely) lateralised weakness. Tongue biting or urinary incontinence may occur, but neither is specific for epileptic seizures. * Tonic-clonic status epilepticus (SE): generalised seizure lasting more than ten minutes. The most severe and dangerous form of epilepsy. * Absence seizure (AS): sudden onset of alteration of consciousness, often with eyelid fluttering. Lasts up to 30 seconds, can occur in clusters over several minutes. Most common in children. #####*Focal* * Clinical features depend upon localisation of the epileptic focus within the brain, but may be motor, sensory or other (*déjà vu* etc.). * May involve alteration in consciousness (complex partial seizure, CPS), or not (simple partial seizure, SPS). * Automatisms (chewing, fidgeting hand movements) may accompany CPS. Focal seizures last seconds to minutes, and are typically stereotyped. * Focal seizures may progress to a generalised seizure or self-terminate abruptly. #####Epilepsy Epilepsy is the condition whereby patients have recurrent seizures that are unprovoked by drugs, toxins, trauma, infection or metabolic disturbance (although these factors and others may also trigger seizures in patients with epilepsy). Epilepsy syndromes may be: * Idiopathic (primary) generalised: probably genetically determined, account for about 20% of epilepsy in the UK, associated with structurally normal brains and usually present before the age of 20 years. Cause generalised seizure types only. * Symptomatic (focal): associated with structural lesions that may act as an epileptogenic focus. Cause focal and secondary generalised seizures. * Unclassified: despite adequate investigation, it is not possible to adequately classify some syndromes. ####Assessment An assessment of the patient with a first seizure, or seizures of recent onset, should be performed promptly (ideally within two weeks) by a specialist in epilepsy.[1] #####Investigations The diagnosis is made on clinical grounds, but investigations are required to aid in syndromic classification, including magnetic resonance imaging (MRI) of the brain and/or an electroencephalogram (EEG) in some cases. All patients should have an electrocardiogram (ECG) to exclude cardiac syncope as a seizure mimic. More complex investigations such as video EEG monitoring or genetic testing may be required in selected cases. ####The treatment of epilepsy #####Which drug The best evidence for the choice of AEDs comes from the SANAD study.[2] The distinction between a focal (FE) or idiopathic generalised (IGE) epilepsy helps guide management. In general, lamotrigine seems to be more effective than other AEDs in the treatment of FE, whereas for IGE valproate was superior to lamotrigine and topiramate, although there are concerns regarding the use of valproate in some patient groups. #####Women with child bearing potential Women with epilepsy may become pregnant, and this must be considered when choosing an AED. In general the risk of seizures to a developing foetus is greater than the risks of AEDs in pregnancy, and mothers should be encouraged to seek pre-conception advice from an epilepsy specialist. Valproate seems to carry a greater risk than other AEDs (up to 7% risk of major congenital malformation, compared with 2-3% for most other AEDs), although small numbers limit the interpretation of some of these data.[3] Notwithstanding, valproate may be the best (and often only) medication for the control of the mother’s epilepsy, and no changes should be made to her drug treatment before an informed discussion of the risks. #####Ketogenic diet Much has been written in both the medical and lay press regarding the ketogenic diet in the treatment of patients with epilepsy. This is primarily a paediatric indication, and to date there is no evidence that it is effective in treatment of adults with epilepsy. ####Epilepsy and death The overall risk of epilepsy varies from patient to patient, dependent on competing influences. #####Prolonged seizures Status epilepticus is the most severe form of epilepsy, and associated with the highest morbidity and mortality (up to 38% in some series), with a lack of evidence on best treatment. Preventing SE remains a priority. Rectal diazepam and buccal midazolam are effective out of hospital treatments. In hospital, treatment with lorazepam (4 mg, intravenous) is superior to diazepam. Where this is ineffective, there is little evidence to guide the next best step, although intravenous phenytoin and phenobarbitone both have established efficacy.[4] #####Sudden unexplained death in epilepsy Sudden unexplained death in epilepsy (SUDEP) has been recognised for some time. It is rare, affecting less than 1:10,000 of patients with epilepsy, although in some groups (i.e. refractory seizures despite adequate AED treatment) the risk can be as high as 1:100.[5] The mode of death is unclear, although there is now some evidence that cardiac asystole may be associated, and AED non-compliance has also been observed. Although some guidelines recommend that SUDEP is discussed with all patients at the time of diagnosis,[1] there is no evidence that this reduces mortality, and there are concerns that it may induce unnecessary psychological morbidity. #####Suicide It is well recognised that patients with epilepsy are at an increased risk of suicide compared with the general population.[6] The reason is not clear, and confounding factors, including socioeconomic status and associated psychiatric disease, have never been adequately excluded. The US Food and Drug Administration issued a warning in 2008 that some AEDs carried a higher risk of suicide than placebo. This has been widely criticised on methodological and ethical grounds, and at present there are no persuasive data to support this association. Nevertheless, patients with epilepsy do have a higher incidence of psychiatric comorbidity (depression, anxiety, psychosis) than the general population. ####Biological effects of seizures Historically, it was assumed that seizures caused epilepsy and brain damage. The former has been proved to be false, while the latter is gathering credibility. #####Seizures do not beget seizures The historical assumption that seizures caused epilepsy has been disproved by the MESS study, which looked at early and delayed treatment of first seizures. This showed no difference in the development of treatment refractory epilepsy in patients treated immediately following a first seizure compared with those randomised to standard treatment (i.e. following second or subsequent seizures).[7] Additionally, given that up to 20% of patients may not develop epilepsy following a first seizure, best practice dictates that treatment should be delayed until the diagnosis is confirmed, by the presence of a second, unprovoked seizure. #####Do seizures damage the brain? That uncontrolled status epilepticus causes brain damage is based on irrefutable evidence, mainly via hypotension, hypoglycaemia, hypoxia, hyperthermia and acidosis. However, there is increasing evidence that both SE and even perhaps brief uncontrolled seizures can also cause cell damage, perhaps contributing to the additional symptoms that patients with refractory epilepsy experience, including behavioural and cognitive changes, learning and memory deficits and mental illness.[8] The mechanisms for this remain poorly defined, but there is mounting evidence to support the contribution of oxidative stress and its downstream cellular effects. This has implications for the development of new AEDs, including the development of neuroprotective agents. ####Conclusions Epilepsy is common at all ages. While the increasing evidence surrounding the disease means that specialisation is unavoidable, awareness of a few basic principles can guide doctors practising in all fields. The use of specialist epilepsy services (neurology, paediatrics, learning disability and nurse specialists) can be supplemented by the increasing number of voluntary organisations (see below for details) who offer support, advice and information to patients with epilepsy. ####Further information * [National Society for Epilepsy website](http://www.epilepsysociety.org.uk/Homepage) * [Epilepsy Action website](http://www.epilepsy.org.uk/) * [Epilepsy.com website](http://www.epilepsy.com/) * [Epilepsy Scotland website](http://www.epilepsyscotland.org.uk/) * SIGN Guideline 70: [*Diagnosis and Management of Epilepsy in Adults.*](http://www.sign.ac.uk/pdf/sign70.pdf) 2009-03-24T11:10:35Z ARC Kelso has previously received educational grants from Sanofi-Synthelabo and GlaxoSmithKline. 107 2009-03-24T00:00:00Z 2009-03-24T00:00:00Z epilepsy 2009-03-24T00:00:00Z

Epilepsy is the most common serious neurological condition in the UK. In this article Dr Andrew Kelso and Dr Richard Davenport outline the different categories of this disease and their treatment options.

2009-03-30T10:29:27Z