Are you sure its a pseudoseizure? Check again. 50% of people with pseudoseizures may also have epilepsy.

Arq Neuropsiquiatr. 2010 Apr;68(2):168-73.

Epilepsy in patients with psychogenic non-epileptic seizures.

Marchetti RL, Kurcgant D, Gallucci-Neto J, Von Bismark MA, Fiore LA.

Source

University of São Paulo School of Medicine, São Paulo, SP, Brazil. rlmarche@bighost.com.br

Abstract

The aim of this study was to evaluate the frequency of epilepsy in patients who presented psychogenic non-epileptic seizures (PNES). The evaluation was carried out during intensive VEEG monitoring in a diagnostic center for epilepsy in a university hospital. The difficulties involved in reaching this diagnosis are discussed. Ninety-eight patients underwent intensive and prolonged video-electroencephalographic (VEEG) monitoring; out of these, a total of 28 patients presented PNES during monitoring. Epilepsy was defined as present when the patient presented epileptic seizures during VEEG monitoring or when, although not presenting epileptic seizures during monitoring, the patient presented unequivocal interictal epileptiform discharges. The frequency of epilepsy in patients with PNES was 50% (14 patients). Our findings suggest that the frequency of epilepsy in patients with PNES is much higher than that of previous studies, and point out the need, at least in some cases, for prolonging the evaluation of patients with PNES who have clinical histories indicating epilepsy.

PMID:

 

20464279

 

[PubMed - indexed for MEDLINE] 

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DISCUSSION

Surely, one of the clinical situations that produce the greatest polemics is the association of epilepsy and PNES. The prevalence of epilepsy in patients with PNES has been estimated as ranging from 5.3 to 73%^3,11-16. This variability in different studies may reflect several methodological characteristics, such as the different inclusion criteria when determining epilepsy and PNES, the presence or not of ictal/interictal EEG abnormalities, the diagnostic environment (inpatient or outpatient), the presence of prolonged monitoring by VEEG, the monitoring duration and the sample size.

This diagnostic issue is extremely important. In the first place, omission of the PNES diagnosis may be very harmful and damaging to patients. Martin et al.²⁰ estimated that the lifetime costs borne by a person with PNES, in diagnostic tests, procedures and treatments would be around US$ 100,000. They also calculated that US$ 100 to 900 million are spent yearly in the USA on the PNES patient population. Several studies have shown that early and appropriate diagnosis of PNES, followed by adequate treatment, may lead to remission in 19 to 52% of cases, or to improvement in 75 to 95% of cases. Therefore, a significant reduction in the use of healthcare systems and in costs is involved^20-23. PNES leads to severe social and psychological consequences. These patients and their families face the same problems as patients with epilepsy: stigmatization, poor schooling, unemployment, difficulties in interpersonal relationships and social exclusion²⁴. From the medical point of view, patients are exposed to iatrogenic procedures, such as the use of high doses of AED²⁵, venous punctures, intravenous AED, and orotracheal intubation²⁶. Moreover, the rate of comorbidity with depressive and anxiety disorders is high^14,21, and the quality of life of these patients is worse than that of patients with difficult-to-control epilepsy²⁷.

On the other hand, to omit the diagnosis of epilepsy may be just as damaging, or even more so. Patients with a diagnosis of PNES may be counseled to halt their AED use and reduce their visits to emergency healthcare facilities, so as to reduce iatrogenic levels and costs^28,29. The treatment may be adapted to a condition of psychogenic nature³⁰. Wyler et al.³¹ dramatically pointed out the possible consequences of these procedures when reporting the case of a 15-year-old girl who perished as a result of an ES that occurred after PNES had been diagnosed by means of VEEG and after medical discharge following AED withdrawal.

This prevalence of epilepsy among patients with PNES was 50% in an epidemiological study carried out in Iceland⁶, but in two recent studies^12,16, relatively low frequencies of epilepsy were found, respectively 5.3 and 9.4%. In our study, this association occurred in 14 patients (50%), a high association level, even though our criteria for diagnosing epilepsy were more restrictive than in both of the abovementioned studies. As in these studies, epilepsy was defined as present when the patient presented ES during VEEG monitoring or otherwise, when unequivocal interictal epileptiform discharges were observed (sharp waves, spikes or complex spike-waves) although no ES occurred. Benign variants were not considered to be epileptiform conditions. However, unlike the two previous studies, interictal epileptiform discharges were considered to be present only when corroborated by clinical validation. Even if we had considered the presence of ES during VEEG monitoring as the one and only criterion for epilepsy, we would have had five patients (18%) under these conditions, i.e. approximately twice the number of both previous studies, presenting relatively low rates of epilepsy.

Following the validation criteria of our study, we concluded that out of the 14 patients with epilepsy, eight (57.1%) were in remission under treatment with AED or after AED withdrawal. Ramsay et al.³² drew attention to the need to distinguish between simultaneous and sequential presence of epilepsy and PNES, when these conditions coexist. According to these authors, their simultaneous presence is easier to establish, due to the probable occurrence of ES during VEEG monitoring, whereas that may not happen when their occurrence is sequential. Usually, in these cases, existence of epilepsy precedes PNESD, complicates it and may, as these authors suggest, be related to the appearance of PNES.

PNES is usually considered to be present when the patient presents complete absence of therapeutic response to AED, or loss of response (therapeutic failure), or perhaps paradoxical responses to AED (worsening or spontaneous and unexpected remission). Moreover, it can occur eventually in function of atypical, multiple, inconsistent or changing pattern seizures, or when these are unleashed by an evident and specific stressful event with close timing connections with the occurrence of seizures³³. The previous elements are particularly considered when the patient presents normal ancillary examinations (interictal routine EEGs and imaging studies such as CT, MRI and SPECT)^34,35. These situations lead the attentive physician to consider the possibility of referral to a center specializing in differential diagnosis and intensive monitoring by VEEG. Out of 22 patients from our sample who were referred for suspected PNES, nine (41%) presented associated epilepsy. Out of six patients in our sample who were referred for other reasons, the presence of epilepsy was not confirmed or observed in only one of them. In these cases, the patients presented PNES as an unexpected phenomenon set within an investigative process directed towards other aims, such as pre-surgical evaluation or diagnostic evaluation of refractory epileptic syndromes. This draws attention to the importance of PNES as a clinical phenomenon that complicates the diagnostic process and treatment of patients with epilepsy.

In one of our cases, the patient presented both spontaneous and suggestion-induced CNEP during VEEG monitoring, but its occurrence was not validated by the medical history data (clinical validation), or by observation of video-recorded events by an external observer with close ties to the patient (observer validation). In this case, although PNES occurred during intensive monitoring by VEEG, we do not believe these represented a real clinical problem. The patient also presented complex partial epileptic seizures during intensive VEEG monitoring, originating from the frontal lobe, which was validated by both clinical and observer validation. This case points out the possibility of isolated PNES occurrence in some gullible individuals, especially when exposed to a favorable situation such as VEEG monitoring¹⁷. It also points out the risk of giving up the investigation far too early because of PNES occurrence, thereby leading to failure to diagnosed epilepsy.

As previously reported, although our criteria may be considered more restrictive than the two previous studies with relatively low rates of epilepsy, our findings suggest that the frequency of epilepsy in patients with PNES is much higher. What might be responsible for these differences? In these three studies, the populations received care in tertiary centers, with patients evaluated for similar reasons. Martin et al.¹⁶ drew attention to the size of their sample (514 patients with CNEP) and to a high rate of referral of patients for suspected PNES. However, out of 22 patients in our sample who were referred on these grounds, nine (41%) presented associated epilepsy. This indicates that, even when the level of suspicion is high for PNES, coexistence of epilepsy may be a significant problem.

One significant difference between our study and others is the period of VEEG monitoring. In previous studies, evaluations typically lasted three days^12,16, and did not exceed five days to one week. In our study, the typical duration of VEEG monitoring was three weeks, with a range from one to six weeks. What was the result of this prolonged monitoring? In most of our patients, PNES presented spontaneous or provoked occurrence, by induction with our protocol of suggestive techniques over the first days of evaluation. Epileptic seizures occurred generally some time after reduction or complete withdrawal of AEDs. In some cases, interictal discharges were registered only after AED withdrawal and a delayed observation period. Lengthening of the monitoring period was usually guided by medical history information, suggesting epilepsy as well as PNES. Possibly, early ending of VEEG monitoring after occurrence of PNES would lead to failure in the diagnosis of epilepsy.

In conclusion, our findings point out the need, at least in some cases, for prolonging the evaluation of patients with PNES and clinical histories indicating epilepsy.