Psychogenic Nonepileptic Seizures (PNES)

Article Author:
J. Stephen Huff
Article Editor:
Najib Murr
Updated:
3/24/2020 4:14:14 PM
PubMed Link:
Psychogenic Nonepileptic Seizures (PNES)

Introduction

Pseudoseizure is an older term for events that appear to be epileptic seizures but in fact do not represent the manifestation of abnormal excessive synchronous cortical activity which defines epileptic seizures. They are not a variation of epilepsy but are of psychiatric origin. Other terms used in the past include hysterical seizures, psychogenic seizures, and others. The most standard current terminology is psychogenic nonepileptic seizures (PNES). Some advocate other terms such as psychogenic functional spells or psychogenic nonepileptic events, spells, or attacks. These terms reinforce the idea that the events are not epileptic seizures.[1][2][3][4][5] A retrospective review of a small number of patients over a number of years revealed that dozens of different diagnostic terms were used to describe these events.[5] Though established in use, the term pseudoseizure and others should be regarded as jargon and the use of psychogenic nonepileptic seizures (or alternatively spells) (PNES) is encouraged for clarity. 

Distinguishing PNES from epileptic seizures may be difficult at the bedside even to experienced observers. In theory, almost any recurrent behavior may represent epileptic seizures. The evolution of epilepsy monitoring units and the ability to utilize simultaneous video and EEG recordings may be a key to diagnosis.[6][7] Video electroencephalography (video-EEG) of a typical event showing the absence of epileptiform activity during the spell with a compatible history is regarded as the gold standard for diagnosis.[8] Diagnostic delay of years with psychogenic nonepileptic seizures is common.[9] 

Treatment of PNES may be difficult, but it is clear that anti-epileptic drugs (AEDs) are of no benefit. In addition to unnecessary costs and the potential side effects of AEDs for these patients, life-threatening side effects such as respiratory depression may occur if psychogenic nonepileptic status epilepticus is treated with large dosages of benzodiazepines.[10] 

Etiology

The most common psychiatric mechanism is thought to be a conversion disorder. A conversion disorder by definition implies that the individual is not aware and is not consciously feigning events. A history of sexual or physical abuse is risk a factor for the development of PNES. The majority of patients are adult women. A disproportionate number of patients with PNES have training in health care careers. How these risk factors summate to produce spells is unclear. Other psychiatric comorbidities may include depression, anxiety disorders, PTSD, or personality disorders. 

Malingering or factitious disorder is thought to be less common as a cause of PNES but might be suspected when there is clear, immediate secondary gain resulting in alterations in behavior.

Epidemiology

The incidence of PNES is unknown. However, in patients admitted to epilepsy monitoring units for unusual or intractable seizures, about 20% to 40% are found to have a diagnosis of PNES rather than epileptic seizures with extended video-EEG monitoring. In a recent study of generalized convulsive status epilepticus, 10% of patients thought to have benzodiazepine-refractory generalized convulsive status epilepticus who were given additional antiepileptic drugs after adjudicated review were found to have PNES.[11]

Pathophysiology

There is some evidence from functional and structural neuroimaging studies that suggest PNES may reflect alterations in sensorimotor, emotional regulation/processing, cognitive control, and integration neural circuits.[8]

History and Physical

Psychogenic nonepileptic seizures may be difficult to distinguish from epileptic seizures. Observation of waxing and waning consciousness, out-of-phase shaking movements, pelvic thrusting, side-to-side head shaking, and eye closure during the event are suggestive of PNES. However, at times brief episodes of sudden unresponsiveness may represent the PNES event. Sometimes, friends or family may volunteer history of nonepileptic seizures or spells, but frequently this is lacking and the patient has been labeled as having a seizure disorder and is being prescribed antiepileptic drugs. 

Even in a busy emergency department, there is always a brief moment of observation before starting treatment. Therapy should not be blindly protocol-driven without some inspection and examination.[12] Most patients with convulsive seizures will have open eyes. Closed eyes, especially tightly closed eyes with resistance to eye-opening during an event are inconsistent with epileptic seizures. Eye closure during spells has consistently been found to be a reliable sign for PNES (95% and above) though occasional exceptions are observed.[13][14][13]

Wild thrashing, side-to-side head movements, and yelling verbal phrases likewise are not consistent with epileptic seizures. Four extremity motor movements with seizures would represent diffuse cortical involvement with an epileptic seizure and the patient should not be able to communicate during such a convulsion. The mouth is usually open during the tonic phase of a generalized convulsion; the presence of a clenched mouth during a tonic spell should raise consideration of PNES.[15] A brief loud noise or similar startle stimulus may be of use to detect PNES since a patient with a generalized epileptic convulsion should not startle or respond to a stimulus during an event. A postical period of somnolence or confusion is common after generalized epileptic seizures but may be absent with PNES.

There are exceptions to these observations. Pelvic thrusting, bicycling movements, abnormal posturing may occur in frontal lobe epilepsy.[16][17][16]  

An increase in heart rate of 30% was observed in patients with epileptic seizures, both convulsive and nonconvulsive, compared to nonepileptic events.[18] Stuttering during an event occurred in about 9% of patients with PNES but was not observed in epileptic seizures in a study from one center.[19] Postictal deep noisy breathing following generalized epileptic seizures was observed in observational studies but not following PNES and is advocated as a useful distinguishing sign.[20] 

With the advent of cameras on cell phones, witnesses to an event may offer a video record. Analysis of these recordings by expert review has been found to have additive value for diagnosing nonepileptic seizures.[21]

Evaluation

Again, observation is key, and clinicians should avoid any rush to unhelpful interventions or treatments.

Correct diagnosis is necessary for successful treatment. Frequently, patients with psychogenic nonepileptic spells have been misdiagnosed as having epilepsy and have been prescribed multiple medications. Consultation with neurology may be helpful. Admission to a monitoring unit may be in order if the diagnosis is uncertain. Long-term video EEG monitoring is the most important diagnostic test.[22] Recently, short-term video-EEG has been found useful in the diagnosis of PNES.[10]

Laboratory testing is of limited utility. Serum prolactin levels have long been noted to increase shortly after a generalized epileptic seizure but not after PNES. Prolactin levels peak quickly after events, and though discussed extensively in the literature, they are of limited pragmatic value. A lactic acidosis commonly follows a generalized convulsion. However, a rise in lactate levels is not specific for convulsions of epileptic origin; elevated lactate levels occurred in volunteers simulating generalized seizures.[23] Elevated creatine kinase levels after generalized convulsive status epilepticus were observed compared to patients with psychogenic nonepileptic status epilepticus and may be useful in distinguishing psychogenic status epilepticus from generalized convulsive status epilepticus.[24]

Treatment / Management

In challenging cases, admission to an epilepsy monitoring unit or similar facility with combined video-EEG monitoring may be needed to secure the diagnosis. The best treatment is not known but may consist of a combination of medication if depression or anxiety exists and cognitive behavioral therapy. An honest and clear discussion of the patient's diagnosis is of utmost importance. In cases of conversion disorder, it is important to acknowledge that the spells are real and cause distress to the patient, family, and friends. It should be articulated that the episodes are not seizures. A respectful approach and the reassurance that supportive therapy will most likely decrease or even eliminate the frequency of spells should be outlined. If the diagnosis of PNES is secure, anti-epileptic drugs should be withdrawn.[25][26] 

Differential Diagnosis

Psychogenic nonepileptic seizures are largely a diagnosis of exclusion. Any paroxysmal event may simulate a seizure or PNES such as syncope, arrhythmia, and other spells. Movement disorders or sleep disorders may be in the differential diagnosis. Once other paroxysmal events are excluded, the distinction between epileptic seizures and PNES may remain a challenge. The differential diagnosis for PNES includes:

  • Absence Seizures
  • Complex Partial Seizures
  • Vertigo
  • Syncope

Prognosis

The prognosis of patients with PNES is not clear. With correct identification of spells and diagnosis of PNES, treatment of any psychiatric co-morbidities and counseling may decrease the frequency of spells. Cognitive-behavioral therapy-informed psychotherapy does seem to be efficacious. Patient acceptance of the diagnosis of PNES is thought to improve outcomes.[8]

Complications

Though sometimes used to "wake up" a patient thought to be having feigned unresponsiveness or nonepileptic spells, noxious stimuli such as ammonia capsules are to be avoided. Communication between health care professionals of observations is essential. 

The recent study of drug regimens in benzodiazepine-refractory generalized convulsive status epilepticus found that 10% of the subjects entered into the study on detailed review were found to have PNES.[11] Potential complications of erroneously treating generalized status epilepticus include adverse reactions to medications. One study found that with the misdiagnosis of PNES as convulsive status epilepticus massive doses of antiepileptic drugs were administered until impaired consciousness or respiratory failure occurred.[12] Unneeded endotracheal intubations with iatrogenic complications have been reported.[27][28]

Deterrence and Patient Education

As discussed previously, the correct diagnosis of PNES is necessary to allow appropriate interventions. Patient and family education about the psychiatric etiology of the spells and withdrawal of antiepileptic medications has been shown to be beneficial in decreasing the frequency of spells.

Pearls and Other Issues

Though the pattern of a generalized convulsive seizure typically is one of abrupt onset, brief tonic posturing followed by synchronized clonic extremity movements, alteration of consciousness, and a postictal confusion phase, exceptions do occur, particularly in patients with partial-onset seizures starting in frontal or temporal areas. At times there are unusual motor patterns with partial-onset seizures or persistent confusional states with minor motor automatisms. If permissible by hospital policies, capturing events with video or smartphones may be useful for later analysis.

Enhancing Healthcare Team Outcomes

A team of healthcare professionals is needed for the ideal treatment of PNES. Team members should be consistent in communication with the patient and family members. Neurologic evaluation and referral to appropriate psychiatric or counseling resources is an ideal course.


References

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