| Psychogenic non-epileptic seizures | |
|---|---|
| Classification and external resources | |
| ICD-10 | F44.5 |
| ICD-9 | 300.11, 780.39 |
| eMedicine | article/1184694 |
Psychogenic non-epileptic seizures (PNES), also known as Non-Epileptic Attack Disorders, are events superficially resembling an epileptic seizure, but without the characteristic electrical discharges associated with epilepsy. Thus, PNES are regarded psychological in origin, and may be thought of as similar to conversion disorder. It is estimated that 20% of seizure patients seen at specialist epilepsy clinics have PNES.[1]
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The differential diagnosis of PNES firstly involves ruling out epilepsy as the cause of the seizure episodes, along with other organic causes of non-epileptic seizures, such as syncope, migraine, vertigo, and stroke, for example. However, it is important to note that between 10-30% of patients with PNES also have epilepsy. Frontal lobe seizures can be mistaken for PNES, though these tend to have shorter duration, stereotyped patterns of movements and occurrence during sleep.[1] Next, factitious disorder (simulating seizures intentionally for psychological reasons) and malingering (simulating seizures intentionally for secondary gain such as compensation or avoidance of criminal punishment) are excluded. Finally other psychiatric conditions that may superficially resemble seizures are eliminated, including panic disorder, schizophrenia, and depersonalisation disorder.[1]
The most conclusive test to distinguish epilepsy from PNES is long term video-EEG monitoring, with the aim of capturing one or two episodes on both videotape and EEG simultaneously (some clinicians may use suggestion to attempt to trigger an episode). Conventional EEG may not be particularly helpful because of a high false-positive rate for abnormal findings in the general population, but also of abnormal findings in patients with some of the psychiatric disorders that can mimic PNES.[1]
According to a study in 23 patients, there is an elevated frequency of childhood abuse, especially in those with motor involvement. A studies has indicated that the metaphors patients use is associated with repressed memories.[2]
Following most tonic-clonic or complex partial epileptic seizures, blood levels of serum prolactin rise, which can be detected by laboratory testing if a sample is taken in the right time window. However, due to false positives and variability in results this test is relied upon less frequently.[1]
The use of older terms including pseudoseizures and hysterical seizures are discouraged.[3] While it is correct that a non-epileptic seizure may resemble an epileptic seizure, pseudo can also connote "false, fraudulent, or pretending to be something that it is not." Non-epileptic seizures are not false, fraudulent, or produced under any sort of pretense.
The condition may also be referred to as non-epileptic attack disorder, functional seizures, or psychogenic non-epileptic seizures. Within DSM IV the attacks are classified as a somatoform disorder, whilst in ICD 10 the term dissociative convulsions, is used, classed as a conversion disorder.[1]
Some features are more or less likely to suggest PNES but they are not conclusive and should be considered within the broader clinical picture. Features that are common in PNES but rarer in epilepsy include: biting the tip of the tongue, seizures lasting more than 2 minutes, seizures having a gradual onset, a fluctuating course of disease severity, the eyes being closed during a seizure, and side to side head movements. Features that are uncommon in PNES include automatisms (automatic complex movements during the seizure), severe tongue biting, biting the inside of the mouth, and incontinence.[1]
If a patient with suspected PNES has an episode during a clinical examination, there are a number of signs that can be elicited to help support or refute the diagnosis of PNES. Compared to patients with epilepsy, patients with PNES will tend to resist having their eyes forced open (if they are closed during the seizure), will stop their hands from hitting their own face if the hand is dropped over the head, and will fixate their eyes in a way suggesting an absence of neurological interference.[1] Mellors et al. warn that such tests are neither conclusive nor impossible for a determined patient with factitious disorder to "pass" through faking convincingly.
Most PNES patients (75%) are women, with onset in the late teens to early twenties being typical.[1] PNES patients often have a history of multiple vague, unexplained medical problems and may have a psychiatric condition such as major depressive disorder or an anxiety disorder. A number of researchers have identified abnormal personality traits or full-blown personality disorders in patients with PNES such as borderline personality. The presence of these personality disorders, often related to a trauma in childhood, has led to researchers postulating that PNES may be an expression of repressed psychological harm in response to trauma such as child abuse. Over-emphasising these theories to patients may lead to false memory syndrome so they should be introduced delicately. Other traumatic experiences such as bullying in adulthood, learning disabilities, or adverse family dynamics may also be important pre-disposing or maintaining factors.[1]
There have been one randomized controlled trials that examined treatment with antidepressive medication in PNES. The study investigated 38 patients and found that those who were treated with Zoloft, got better effect than those treated with placebo [4].
An important first step is a discussion with the patient that explains their diagnosis in a sensitive and open manner. A negative diagnosis experience will frustrate the patient and could cause them to reject any further attempts at treatment.[1] Ten points to breaking the diagnosis to the person and their carers are:
Psychotherapy is the most frequently used treatment, which might include cognitive behavioral therapy, insight-orientated therapy, and/or group work. Where there is a co-morbid psychiatric condition, treatment with antidepressant medication can be helpful.[1]
Though there is limited evidence, outcomes appear to be relatively poor with a review of outcome studies finding that two thirds of PNES patients continue to experience episodes and more than half are dependent on social security at three year followup.[5] This outcome data was obtained in a referral-based academic epilepsy center and loss to followup was considerable; the authors point out ways in which this may have biased their outcome data.
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