What is PNES (Psychogenic Non-Epileptic Seizures)?
PNES are paroxysmal episodes involving motor, sensory, mental, or autonomic manifestations that resemble epileptic seizures but lack epileptogenic brain activity and are instead caused by psychological mechanisms. 1, 2
Definition and Epidemiology
- PNES represent a significant diagnostic challenge, affecting 20-30% of patients attending epilepsy centers and over 10% of seizure emergencies 1, 3
- These episodes are classified as Functional Neurological Disorder/Conversion Disorder in DSM-5, though they appear under dissociative disorders in ICD-10/11 2, 4
- The mean delay between symptom onset and correct diagnosis remains approximately 7 years, during which many patients are incorrectly treated with antiepileptic medications 4
- Approximately 65-80% of PNES patients are young females, though a subgroup of older men has been recently identified 4
Key Clinical Features That Distinguish PNES from Epileptic Seizures
Movement Characteristics
- PNES demonstrate asynchronous, side-to-side thrashing movements, while epileptic seizures show symmetrical, synchronous bilateral movements 1
- Repeated waxing and waning in intensity with changes in the nature of movement strongly suggests PNES 5
- Pelvic thrusting is characteristic of PNES (though rarely seen in frontal lobe seizures) 5
- Eye fluttering is more likely in PNES than epileptic seizures 6
Duration and Consciousness
- PNES typically last less than 30 seconds, compared to 74-90 seconds for epileptic seizures 1
- Episodes lasting longer than 5 minutes suggest PNES rather than epileptic seizures 5
- Eyes are typically closed during PNES, whereas they remain open during generalized epileptic seizures 1, 6
Physical Signs
- Lateral tongue biting is highly specific for epileptic seizures and uncommon in PNES 1
- Urinary incontinence does not differentiate between epileptic seizures and PNES 5
Diagnostic Approach
Gold Standard
- Video-EEG monitoring is the gold standard for diagnosis when clinical uncertainty exists 6, 4
- This can identify the 20-30% of "epilepsy center" patients who actually have PNES rather than epilepsy 6
Common Diagnostic Pitfalls to Avoid
- Do not rely on biomarkers such as neuron-specific enolase, prolactin, and creatine kinase to differentiate PNES from epilepsy, as these are not reliable 1, 6, 4
- Complex partial seizures of frontal origin can present with similar characteristics to PNES and may be confused with the latter 4, 7
- Note that 10-30% of PNES patients may also have comorbid epilepsy, making diagnosis more complex 4, 3
Associated Psychiatric Comorbidities
- PNES patients have high rates of psychiatric disorders including depression, anxiety, somatoform symptoms, dissociative disorders, and post-traumatic stress disorder 4, 3
- Strong evidence exists for correlations between childhood trauma, history of childhood abuse, PTSD, and PNES diagnoses 4, 3
- PNES can be conceptualized as dissociative phenomena generated by trauma, operating as a defensive psychological mechanism 2, 4
Management Principles
Diagnosis Communication
- Communicate the diagnosis directly and sympathetically to the patient, acknowledging that the episodes are involuntary, real (not faked), represent a conversion disorder, and are treatable with appropriate psychological interventions 6
Treatment
- Cognitive behavioral therapy (CBT) is the first-line treatment for PNES 6
- Pharmacotherapy has no demonstrated benefit for PNES itself 6
- A multidisciplinary approach involving both psychiatry and neurology is beneficial, with neurologist follow-up remaining essential post-diagnosis 4
Prognosis
- Quality of life can be improved with treatment even when complete seizure freedom is not achieved 6, 8
- 72% of PNES patients show resolution after psychiatric treatment in follow-up studies 6
- However, nearly half of patients who become seizure-free remain unproductive, and many continue to have symptoms of psychopathology including other somatoform, depressive, and anxiety disorders 4