This blog’s title depicts a common way in which many doctors explain the diagnosis of Psychogenic non-epileptic seizures (PNES) to patients who are newly diagnosed with this disorder. I suspect this presentation is meant to suggest to the patient that having PNES is less terrible, dangerous, maybe potentially intractable, etc. than having epilepsy. However, in this year’s American Epilepsy Society meeting there was a very interesting poster that questioned this viewpoint.
The poster’s title was unambiguous and succinct: (Abst. 1.139) MORTALITY IN PATIENTS WITH PSYCHOGENIC NON-EPILEPTIC SEIZURES
I am going to summarize and comment on the abstract below. I will say that I was hoping to ask the authors many more questions on the day their poster was being displayed but I got there just minutes before the end of the display time and I missed them. So, unfortunately, I am left with what I was able to glean from the poster all by myself.
Basically, the goal of the study was to compare patients with PNES to those persons with epilepsy (PWEs). PWEs were used as a comparison group because they tend to have an elevated risk of death compared with the general population.
The study was retrospective which means that it was done by reviewing (or looking back at) existing charts and data in patients who had been evaluated at one of two inpatient video EEG monitoring units in Melbourne Australia from January 1st 1995 to December 31st 2015. The authors determined mortality and cause of death by checking the Australian National Death Index (NDI) and information from the National Coronial Information System (NCIS) where a coroner’s report was available. Patients diagnosed with PNES, epilepsy or both conditions were compared. In addition, a lifetime history of psychiatric disorders was extracted from neuropsychiatric reports. In the end, 2076 patients were included in the study, 631 PNES cases, 1339 epilepsy and 106 with dual diagnosis (PNES and epilepsy). They found that those diagnosed with PNES had a standardized mortality ratio (SMR) 2.6 times greater than the general population (95% CI 2.0-3.4). Moreover, those between the ages of 30 and 39 had a 9-fold higher risk of death (95% CI 4.9-17). More surprisingly, there was no significant difference in the rate of mortality between any of the patient groups after excluding epilepsy patients with a known brain tumor at the time they were tested on the epilepsy monitoring unit, or who had a malignant neoplasm of the brain listed as their primary cause of death. The authors also reported that “External causes of death account for 20% of all deaths in those in the PNES group.” Unfortunately, they did not provide more details about these “external causes.” Suicide accounted for 24% of deaths in PNES in those younger than 50 years. Neoplasia and cardiorespiratory causes were responsible for 51% of deaths with a known cause across all ages.
In sum, the authors concluded that patients with PNES had an SMR over 2.5 times greater than the general population, and in fact were dying at a rate comparable to those with drug resistant epilepsy!
So, the usual spiel of “the good news is that you don’t have epilepsy, instead you have something called PNES” may need to be reworded. PNES is, like many of us already know, a serious, potentially dangerous and disabling health disorder. And now if we are reading these results right, is also associated to strikingly elevated mortality rates.
I guess the next question we are left with is, why this high mortality? Obviously, I suspect that psychiatric comorbidities can play a role in these numbers through suicide but also through poor physical health associated to depression, anxiety and especially post-traumatic stress disorder (PTSD). I also suspect if carrying an incorrect diagnosis that is accompanied by an average of 7 years of treatment with anti-epileptic drugs, emergency room visits, injuries secondary to seizures, limited mobility, financial limitations resulting from lost wages, social isolation, etc. may also play a role in this. Finally, I think we need to end this particular blog post by stating, we have much to understand and learn about PNES and this poster has made an important and intriguing contribution this year.
Here is the link to the full poster: https://www.aesnet.org/meetings_events/annual_meeting_abstracts/view/498473