The Approach to Patients with ''Non-Epileptic Seizures''

498 Postgrad Med J: first published as 10.1136/pgmj.2004.029785 on 5 August 2005. Downloaded from REVIEW The approach to patients with ‘‘non-epileptic seizures’’ J D C Mellers ............................................................................................................................... Postgrad Med J 2005;81:498–504. doi: 10.1136/pgmj.2004.029785 Up to one fifth of patients who present to specialist clinics with loose shorthand to refer to the psychological attacks alone.12 The terms psychogenic NES and seizures do not have epilepsy. The majority of such patients functional seizures overcome some of these suffer from psychologically mediated episodes; dissociative objections but formal psychiatric classification seizures, often referred to as ‘‘non-epileptic seizures’’. This systems provide clearly defined labels. Unfor- tunately, though, there are still inconsistencies: paper describes the diagnostic evaluation of seizure thus, within DSM IV13 such attacks are classified disorders, including clinical assessment and the role of special under somatoform disorder and in ICD 1014 the investigations. The organic and psychiatric imitators of diagnostic label ‘‘dissociative convulsions’’, is classified within the group of conversion dis- epilepsy are outlined and findings on psychiatric assessment orders. It is the latter terminology that will be are reviewed. This group of patients often proves difficult to adopted here. engage in appropriate treatment and an approach to As we have seen, dissociative convulsions or seizures (DS) are common, the diagnosis is often explaining the diagnosis is described. As yet there are no missed, and when it is patients not only fail to controlled trials of treatment in this disorder but preliminary receive appropriate treatment but are subject to evidence suggests cognitive behavioural therapy is both a unnecessary, costly,15 and potentially harmful medical interventions. In considering the man- rational and promising way forward. agement of this disorder we will therefore focus ........................................................................... on assessment and diagnosis before considering contemporary approaches to treatment. p to one in five patients with apparently intractable epilepsy referred to specialist CLINICAL ASSESSMENT centres are found to have no organic cause It should be emphasised from the start that U 1–4 for their seizures. It has been widely supposed epilepsy is primarily a clinical diagnosis. Great that this high prevalence reflects referral bias but care must be taken to establish the precise a recent community based study found a similar sequence of events during an attack and history proportion among patients with recent onset taking is not complete until an eyewitness seizures.5 This group of patients suffer from account has been obtained. The duration of each psychologically mediated paroxysmal beha- phase of symptoms, including recovery from the http://pmj.bmj.com/ vioural disturbances that are often dramatic, attack, should be determined. Any habitual alarming for bystanders, and all too easily pattern in the circumstances that trigger attacks mistaken for epilepsy. Diagnostic errors are the should be sought. Patients and eyewitnesses rule rather than an exception. Most patients are should be prompted for specific symptoms treated for epilepsy for several years67and by the because significant features may not be men- time the correct diagnosis is made they will tioned spontaneously (for example, psychic and commonly have taken more antiepileptic drugs cognitive symptoms, automatisms, occurrence (AEDs) at higher doses and experience more side during sleep). on September 30, 2021 by guest. Protected copyright. effects than an equivalent cohort of patients with 89 epilepsy. One in 10 patients will present in Medical differential diagnosis apparent status epilepticus.178 Astonishingly, The box lists the medical and psychiatric about one quarter of referrals to a specialist differential diagnosis for epilepsy (see Cook16 neurological intensive care unit with refractory and Andermann17 for a review). Of medical status were found to have ‘‘pseudostatus’’.10 disorders mistaken for epilepsy syncope is the What this disorder should be called has been most common3 and in non-specialist settings is the subject of considerable debate. Some terms the condition most likely to be misdiagnosed as (hysterical seizures, pseudoseizures) are pejora- epileptic. It is important to note that tonic or ....................... tive, unacceptable to patients,11 and have largely clonic movements may be seen during syncope.18 Correspondence to: been abandoned. Others (non-epileptic seizures However, characteristic prodromal symptoms Dr J D C Mellers, (NES), non-epileptic attack disorder) merely (lightheadedness, clammy sweatiness, a sense Department of describe what the condition is not, rather than of receding sound and vision, nausea), associated Neuropsychiatry, Room conveying what it is. Furthermore, these terms 32, Outpatient cardiac symptoms, and a relation in some cases Department, Maudsley have been used with different meanings: the to postural changes or valsalva usually make Hospital, Denmark Hill, term NES, for example, is sometimes used to identifying cases of syncope straightforward.19 20 London SE5 8AZ, UK refer to the group of neurological, cardiological, In patients with cerebrovascular disease the and other medical conditions, in addition to Submitted15October2004 Accepted psychiatric disorders, which constitute the Abbreviations: AED, antiepileptic drug; NES, non- 4 14 December 2004 differential diagnosis for epilepsy, while on epileptic seizure; DS, dissociative seizure; ES, epileptic ....................... other occasions the term is used as a form of seizure; CBT, cognitive behavioural therapy www.postgradmedj.com Non-epileptic seizures 499 Postgrad Med J: first published as 10.1136/pgmj.2004.029785 on 5 August 2005. Downloaded from differentiation of transient ischaemic attacks from partial that must be considered: (1) dissociative seizures; (2) seizures may sometimes be difficult. Ischaemic episodes may factitious disorder; (3) other psychiatric disorders that have last for seconds to minutes but usually occur with preserved been mistaken for epilepsy. Dealing with the last category consciousness, are associated only with a loss of function, first, paroxysmal symptoms of psychiatric disorders may and are not followed by more typical epileptic features. A sometimes raise the question of epilepsy. The most common comparatively long duration of symptoms is useful in example of this is panic disorder.25 Patients may report recognising migraine, migraine equivalents (the latter featur- depersonalisation, derealisation, and tremulousness during ing prodromal symptoms but no headache),21 and vertigo. panic attacks while partial epileptic seizures may include Abnormal startle phenomena, including hyperekplexia, are both emotional and somatic symptoms of anxiety.26 Features rare but often mistaken for epilepsy and need to be that are useful in distinguishing the two conditions include a distinguished from startle induced seizures.17 22 Paroxysmal longer duration, cognitive symptoms, and the presence of movement disorders may be mistaken for epilepsy.23 Sudden specific environmental triggers in panic disorder and, in loss of muscle tone that may produce falls in response to an partial seizures, the unique quality of the emotional emotional trigger suggest cataplexy, which is usually found symptoms (‘‘ictal fear’’) together with associated more in association with other features of the narcolepsy syndrome characteristic epileptic features in partial seizures. (narcolepsy, hypnopompic or hypnogogic hallucinations, and Paroxysmal symptoms in psychosis may sometimes raise sleep paralysis). Other parasomnias giving rise to complex the question of epilepsy but such symptoms (for example, behavioural episodes arising from sleep may be confused hallucinations) lack the highly stereotyped quality of with epileptic automatisms although the former lack any epileptic phenomena and episodes are usually of long and preceding ictus and are usually of comparatively long variable duration. Other psychiatric disorders sometimes duration.24 Space occupying lesions in the 3rd ventricle may confused with epilepsy include depersonalisation disorder produce intermittent CSF obstruction associated with visual and attention deficit hyperactivity disorder in which failing symptoms and are a rare cause of sudden episodes of collapse school performance and poor concentration may sometimes with loss of consciousness. Metabolic disorders associated raise the possibility of juvenile absence epilepsy. with loss of consciousness usually have a protracted time In most cases, however, the seizures will be the principal course and are suggested by other features in the history. symptom and cannot be accounted for by another psychiatric condition. The two diagnostic possibilities are dissociative seizures and factitious disorder distinguished from one Psychiatric differential diagnosis another by whether the seizures are thought to arise through Once epilepsy and other organic causes of seizures have been unconscious processes (DS) or are deliberately enacted. In excluded there are three categories of psychiatric diagnoses factitious disorder the patient is held to be deliberately simulating epilepsy for reasons understandable in terms of their psychological background. It is distinguished

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