Non-Epileptic Psychogenic Seizures: a Neurologist's Perspective
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Non-Epileptic Psychogenic Seizures: a Neurologist’s Perspective Andrea O. Rossetti Service de Neurologie, CHUV, Lausanne Summary Crises non-épileptiques psychogénes depuis une perspective neurologique Psychogenic non-epileptic seizures (PNES) represent a relatively frequent challenge for clinicians. While they Les crises non-épileptiques psychogènes repré- resemble epileptic seizures, they are not the conse- sentent un défi relativement fréquent pour les neuro- quence of paroxysmal electrical discharges in the brain, logues. Si d’une part ces manifestations ressemblent but are related to psychological triggers in vulnerable à des crises épileptiques, elles ne sont pas dues à des subjects. Gold standard of PNES diagnosis remains the décharges neuronales paroxystiques, mais sont liées à recording of a typical event under video-EEG. PNES rec- des facteurs déclenchants d’ordre psychologique surve- ognition is not only important in order to offer an ap- nant chez des sujets vulnérables. Le gold-standard pour propriate treatment to the patient, which should in- le diagnostic des crises non-épileptiques psychogènes clude a multidisciplinary approach by psychiatrists and est l’enregistrement d’un événement typique sous neurologists, but also, especially in the acute phase, to vidéo-EEG. L’identification de patients avec crises non- avoid a potentially harmful escalation of pharmacologi- épileptiques psychogènes est non seulement impor- cal treatment. tant pour offrir aux malades un traitement approprié (idéalement par une approche interdisciplinaire avec Epileptologie 2016; 33: 50 – 54 psychiatre et neurologue), mais aussi afin d’éviter une surenchère médicamenteuse qui peut se révéler dange- Key words: PNES, dissociative disorder, conversion disor- reuse, particulièrement dans la phase aiguë. der, diagnosis, psychiatrist Mots clés : Trouble dissociatif, trouble somatoforme, trouble de conversion, diagnostic, psychiatre Nichtepileptische, psychogene Anfälle aus der Neurologenperspektive Why are psychogenic non-epileptic seizures im- Nichtepileptische, psychogene Anfälle stellen eine portant? relativ häufige Herausforderung für Neurologen dar. Auf der einen Seite ähneln diese Ereignisse epilepti- Psychogenic non-epileptic seizures (PNES) are de- schen Anfällen, sie sind aber nicht das Resultat einer fined as paroxysmal disorders that clinically resemble paroxysmalen neuronalen Entladung, sondern bei vul- epileptic seizures, but occur without epilepsy-specific nerablen Patienten mit psychologischen Auslösefakto- changes on the EEG, together with a psychological ren verbunden. Der Gold-Standard der Diagnose ist die substrate [1]. Furthermore, PNES patients, as opposed Video-EEG-Aufnahme einer charakteristischen Episo- to subjects with convulsive seizures, do not show any de. Die Identifizierung der Patienten mit nichtepilep- meaningful elevation of muscle CK or lactate [2], and as tischen psychogenen Anfällen ist nicht nur wegen der opposed to patients after an organic syncope or seizure, Möglichkeit einer adäquaten Therapieeinleitung wich- do not have any modification in serum prolactine. tig, welche idealerweise durch einen multidisziplinären PNES patients are not rare, especially for epilep- Ansatz von Psychiatern und Neurologen durchgeführt tologists or for neurologists working in a hospital. Up werden sollte, sondern auch, um eine in der Akutpha- to 20% of patients with PNES may present a “status”, se möglicherweise gefährliche Therapieeskalierung zu meaning that their attacks are prolonged over several vermeiden. minutes to hours [3]; and a considerable proportion of patients treated in the intensive care unit for suspect- Schlüsselwörter: PNES, dissoziative Anfälle, Konversions- ed status epilepticus may finally receive a diagnosis störung, Diagnose, Psychiater of PNES [2]. This may lead to potentially inappropriate treatments, as up to 60% of patients are treated with antiepileptic drugs (AEDs), which do not prevent PNES episodes [4], and an escalation to an intensive care 50 Epileptologie 2016; 33 Non-Epileptic Psychogenic Seizures: a Neurologist’s Perspective | A. O. Rossetti admission and tracheal intubation may induce a non patients with PNES exhibit a strong psychiatric comor- negligible morbidity and mortality of iatrogenic ori- bidity, mostly in terms of anxio-depressive disorders, gin. These patients may have a history or show signs of but also regarding personality disorders (particularly, other non-organic disorders [5]. Finally, PNES patients narcissistic or histrionic, but also unstable personalities show a higher yearly mortality rate as compared to such as borderline) [1, 9]. As stated above, other signs matched controls [6]. For all these reasons, the ability and symptoms of dissociative disorders are not infre- to recognize PNES is of utmost importance for the well- quent, both as concomitant diagnoses, and as occur- being of patients. rences in the patient’s history. In recent years, some attention has been directed towards identifications of biological markers in this Epidemiology clinical context; all studies have been conducted inter- ictally. Decreased metabolism in the anterior cingulate Table 1 gives an overview of estimations of PNES cortex (a key location for integration of the self) and in incidence, while the prevalence has been estimated at the right pericentral cortical regions (subtending orien- 2-33/100’000 population [7]. These numbers represent tation in space and movement control) has been iden- about 1/15, respectively 1/100 of the epilepsy incidence tified with PET [10]. A functional MRI study suggested and prevalence; however, a considerable proportion of that PNES patients show stronger connectivity values PNES patients may go unrecognized, as it is relatively between areas involved in emotion (insula), executive common to diagnose patients several years (up to 20) control (inferior frontal gyrus and parietal cortex), and after symptom onset [8]. In all studies, there is a preva- movement (precentral sulcus) [11], suggesting a sort lence of women. This is especially true for middle-aged of short circuit facilitating dissociative manifestations, patients. Table 2 summarizes data regarding comor- while high-density EEG studies detected a disconnec- bidity with epilepsy, which seems to oscillate between tion of the frontal regions, whose extent correlated with 10 and 20%. A consistent proportion of PNES patients, the density of PNES attacks overt time [12, 13]. A follow- thus, may have concomitant epileptic attacks; in the ex- up analysis showed in addition a decrease in connectiv- perience of the author, however, patients can report in ity between basal ganglia and several cortical regions, most cases the difference between these two entities. suggesting a correlate of attenuation of the effect of po- tentially disturbing mental representations [8]. Causes Semiology and differentiation from epileptic sei- The classical psychodynamic theory explains PNES zures as part of dissociative or somatoform disorders as an unconscious development of a somatic symptom that As with epileptic seizures, the great inter- (and at reduces an inner tension in patients with some sort of times intra-) individual variability of symptoms justifies unsolved psychological conflicts. In fact, virtually all some classification attempts. One relatively straightfor- Table 1: Yearly incidence of psychogenic non-epileptic seizures (PNES) Location Incidence/100’000 Women Age range Reference Iceland 1.4 79% 16 - 54 [14] Ohio (USA) 3.0 73% >18 [15] Scotland 4.9 81% 14 - 71 [16] Non-Epileptic Psychogenic Seizures: a Neurologist’s Perspective | A. O. Rossetti Epileptologie 2016; 33 51 Table 2: Proportion of patients with psychogenic non-epileptic seizures (PNES) also having epilepsy Location Cohort Proportion Reference Iceland population 50% [14] Ohio (USA) population 20% [15] Florida (USA) hospital 9% [17] Shiraz (Iran) hospital 16% [18] Lausanne (CH) hospital 22% [19] ward approach categorizes motor episodes into three cording. A debate exists regarding the use of a nocebo, main groups: overt motor manifestations (resembling particularly injection of physiological saline under sug- generalized convulsive seizures), subtle motor manifes- gestion [29, 30]. It is the opinion of this author that tations (resembling temporal lobe seizures), and atonic nocebo has its place if other maneuvers do not allow manifestations (resembling syncope) [20, 21]. Interest- an attack induction. However, it is of greatest impor- ingly, it has been shown that younger patients tend to tance how to verbally reinforce the injection: stating present significantly less often with overt motor epi- that “the liquid will induce an epileptic seizure” is not sodes as compared to adults [22]. only incorrect but also deceives the patient; conversely, Surveys among neurologists illustrated that PNES saying that “the diluted salt may induce a characteristic diagnosis solely based upon semiology has a sensitiv- attack that will enable a correct diagnosis” is both well ity and specificity of 80 - 85% [23], while the interrater accepted and potentially very helpful. agreement seems moderate for PNES and substantial Differential diagnoses with physiological disorders for epileptic seizures [24]. Clinical items that help in dif- include, in the order of frequency (but in an incomplete ferentiating PNES from epileptic seizures are given in listing): syncope, (frontal lobe) seizures, migraine with Table 3. It is important to underscore that no sign bears aura,