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|Psychogenic non-epileptic seizures|
|Classification and external resources|
Psychogenic non-epileptic seizures (PNES) are events resembling an epileptic seizure, but without the characteristic electrical discharges associated with epilepsy. They are of psychological origin, and are one type of non-epileptic seizure mimics. PNES are also known less specifically as non-epileptic attack disorder (NEAD) and functional neurological symptom disorder.
People present with episodes that resemble seizures, and most have received a diagnosis of epilepsy and treatment for it. Most commonly the episodes in question are convulsive (whole body shaking) and resemble generalized tonic-clonic (“grand mal”) seizures, but they can be less dramatic and mimic milder types of seizures (partial seizures, absence seizures, myoclonic seizures).
Most people with PNES (75%) are women, with onset in the late teens to early twenties being typical.
A number of studies have also reported a high incidence of abnormal personality traits or personality disorders in people with PNES such as borderline personality. However, again, when an appropriate control group is used, the incidence of such characteristics is not always higher in PNES than in similar illnesses arising due to organic disease (e.g., epilepsy).
Other risk factors for PNES include having a diagnosis of epilepsy, having recently had a head injury or recently undergone neurosurgery.
The cause is by definition psychological, and can be categorized into several different psychiatric diagnoses. In the vast majority of people, the production of seizure-like symptoms is not under voluntary control, (i.e., the person is not faking). There are several diagnoses defined by the unconscious production of physical symptoms, including seizure-like events. A history of abuse or other psychological trauma is often present as a causative factor.
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, including syncope, migraine, vertigo, anoxia, hypoglycemia, and stroke. However, between 5-20% of people 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. Next, an exclusion of factitious disorder (a subconscious somatic symptom disorder, where seizures are caused by psychological reasons) and malingering (simulating seizures intentionally for conscious personal gain – such as monetary compensation or avoidance of criminal punishment) is conducted. Finally other psychiatric conditions that may superficially resemble seizures are eliminated, including panic disorder, schizophrenia, and depersonalisation disorder.
The most definitive test to distinguish epilepsy from PNES is long term video-EEG monitoring, with the aim of capturing one or two episodes on both video recording and EEG simultaneously (some clinicians may use suggestion to attempt to trigger an episode). Additional clinical criteria are usually considered in addition to video-EEG monitoring when diagnosing PNES.
EEG-video monitoring will usually answer the following questions:
By recording the event in question on video and EEG simultaneously, a clear diagnosis can usually be obtained.
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.
Terminology varies somewhat, although PNES has become the most widely accepted term. The use of older terms including pseudoseizures and hysterical seizures are discouraged. In the English language, the word “seizure” usually refers to epileptic events, so some prefer to use more general terms like "events," "attacks," or "episodes," as the term “seizures” often causes confusion with those affected and families.
PNES may also be referred to as "non-epileptic attack disorder" or "functional seizures," though those terms do not clearly indicate a psychological origin and therefore include other (non psychological) causes of epilepsy mimics. Within DSM IV the attacks are classified as a somatoform disorder, whilst in ICD 10 the term dissociative convulsions is used, classified as a conversion disorder. In DSM-5 PNES is also known as functional neurological symptom disorder and is classified as a conversion disorder, which falls under the diagnostic category of somatic symptom disorders.
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 (easiest factor to distinguish), 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.
If a person 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 people with epilepsy, people 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. Mellers et al. warn that such tests are neither conclusive nor impossible for a determined person with factitious disorder to "pass" through faking convincingly.
People with PNES have typically carried a diagnosis of epilepsy for roughly 7 years, so an understanding of the new diagnosis is crucial for their treatment, which requires their active participation. There are a number of recommended steps to explain to people their diagnosis in a sensitive and open manner. A negative diagnosis experience may cause frustration and could cause a person to reject any further attempts at treatment. Ten points recommended to explain the diagnosis to the person and their caregivers are:
Psychotherapy is the most frequently used treatment, which might include cognitive behavioral therapy, insight-orientated therapy, and/or group work. There is also some evidence supporting selective serotonin reuptake inhibitor antidepressants. Mental health professionals typically show little interest in this category of psychiatric diseases and people frequently find themselves stuck between psychiatry and neurology with no one to turn to for treatment.
Though there is limited evidence, outcomes appear to be relatively poor with a review of outcome studies finding that two thirds of people with PNES continue to experience episodes and more than half are dependent on social security at three-year followup. This outcome data was obtained in a referral-based academic epilepsy center and loss to follow-up was considerable; the authors point out ways in which this may have biased their outcome data. Outcome was shown to be better in people with higher IQ, social status, greater educational attainments, younger age of onset and diagnosis, attacks with less dramatic features, and fewer additional somatoform complaints.
The incidence and prevalence of PNES in the general population are difficult to determine, but PNES are consistently found in 20-40% of inpatients at epilepsy centers. Like other somatic symptom disorders, PNES are most common in young adults and women.
PNES are seen in children after the age of 8, and occur equally among boys and girls before puberty. Diagnostic and treatment principles are similar to those for adults, except that in children there is a broader differential diagnosis of seizures so that other possible diagnoses specific to children may be considered.
Hystero-epilepsy is a historical term that refers to a condition described by 19th-century French neurologist Jean-Martin Charcot where people with neuroses "acquired" symptoms resembling seizures as a result of being treated on the same ward as people who genuinely had epilepsy.
PNES rates and presenting symptoms are somewhat dependent on the culture and society. In some cultures they, like epilepsy, can be considered a curse or a demonic possession. In western culture, they are a subtype of a larger category of psychiatric disease.