By Jennifer Brown
Neuropathic-like Pain in Functional Neurological Disorder
Neuropathic pain is pain caused by neurological lesions or diseases, characterized by a wide range of pain symptoms, including spontaneous and evoked pain due to increased sensitivity; neuropathic pain is likewise associated with paraesthesia, numbness, tingling, and sensory, motor, and cognitive deficits (Bouhassira, 2019; Mitsikostas et al., 2022). Interestingly, however, neuropathic-like pain is associated with functional neurological disorder (FND) symptoms, neurological symptoms that have no underlying medical cause that can be seen through standard testing (Mason et al., 2023; Pan et al., 2020). While neuropathic symptoms can occur in FND, they are often assumed to be from a psychological cause, not a true medical condition.
Nonetheless, these similarities may indicate that the underlying mechanisms of functional neurological disorder (FND) are more biologically based than initially suspected. In my case, I developed unexplained neurological symptoms in 2020; however, I have experienced a wide range of symptoms throughout the past three years, including neuropathic-like symptoms. While it is generally accepted that FND results from mental illness, a discussion of the similarities between neuropathic pain and FND is needed to fully understand the depth of this condition beyond the limitations of current research. The following is a personal account of my neurological and neuropathic symptoms over the past three years with FND.
Per Mitsikostas et al. (2022), neuropathic pain can be seen among certain neurological disorders and other associated conditions. Specifically, Mitsikostas et al. (2022) lists neuropathic pain among endocrine dysfunction, viral infections, trauma, and neurological diseases such as multiple sclerosis, stroke, peripheral neuropathy, and centralized pain syndromes. Interestingly, Mason et al. (2023) studied patients with FND who attend chronic pain clinics. Researchers discovered that among chronic pain symptoms, 20% of patients displayed neuropathic pain (Mason et al., 2023). Specifically, Mason et al. (2023) found that patients with FND were likelier to have a primary type of chronic pain of widespread conditions, such as fibromyalgia, than the secondary type. Moreover, Mason et al. (2023) found an overlap between patients with functional motor and sensory disorders and chronic regional pain syndrome.
These findings suggest that while functional symptom etiology has been primarily accepted as psychological, the development of neuropathic-type pain must, in some respect, cross paths with the underlying mechanisms of neuropathic disorders to display similar symptomology. In other words, the cause of the neurological symptoms in the participants in this study likely has a relationship with true neurological dysfunction. This is valid, at the very least, as some of the patients in this study also displayed true neurological disorders (disorders proved to be caused by neurological mechanisms), such as epilepsy and stroke (Mason et al., 2023). If this is untrue, we must ask ourselves what means can produce two causes of the same symptoms.
In my personal experience, my FND symptoms have similarities between neurological and neuropathic-like pain. In 2020, I started to have spells of dizziness and confusion, often associated with headaches. Over time, the dizziness developed into episodes of drop attacks, attacks where my body would give out and drop to the floor. In these episodes, it looked like I fainted; however, unlike regular syncope episodes, I remained conscious during these situations. By the end of 2020, I underwent extensive medical testing and was eventually told I had FND. I was told there was nothing to worry about as these events would stop independently.
By summer 2021, however, I was experiencing daily episodes of extreme dizziness and confusion, accompanied by nausea and headaches. I noticed these drop attacks often occur upon standing, so I consciously tried to sit more and be less active. By November 2021, my symptoms shifted. I stopped having drop attacks and started having seizure-like episodes. My first seizure happened when I was on leave visiting home. I was resting at home and began to feel a tightness in my chest and a pulse-like sensation that vibrated my chest. Before I knew what was happening, my chest started jerking with a pulse-like sense. I was completely conscious and aware of what was happening but unsure of what to do. Over a series of a few days, I had a number of these seizure-like episodes and eventually went to the ER. Not surprisingly, though, I was told these episodes were “psychogenic” or non-epileptic, and I only needed to see a psychiatrist.
Since then, I have had two normal EEGs and have been medically cleared. I have done every therapy recommended and am in the best mental health mindset ever. Despite reassurance that nothing is wrong with me, I still experience significant symptoms. I have now developed neuropathic-like symptoms, most significantly experienced right before seizures, such as numbness and tingling on my right side of the body and face and jerking on the right side. These symptoms can persist after these episodes, which, along with fatigue and confusion, can make it difficult to do daily activities. Symptoms such as these can come on at any moment and become fierce. For example, a few months ago, I tried an alternative treatment to help with my attacks. However, I ended up with escalating seizures ranging from an intense 15-minute seizure to a 40-minute seizure to a seizure every minute for 1.5 days (I had approximately 800 30-second seizures and 30 seconds of rest).
Ending comment
While this is only my story, this is a small but significant example of how somewhat "random" neurological symptoms can become debilitating. My case is not unusual for those with FND. Many with FND experience various symptoms, including motor deficits and movement disorders, cognitive deficits, functional stroke attacks, functional seizures (non-epileptic seizures), paralysis, trouble speaking, and much more. With the consensus primarily being that FND and psychogenic non-epileptic seizures are purely psychological and caused by emotional distress, those with FND often experience significant stigma, dismissal, and often a refusal to be seen (mainly from those who strongly believe there is nothing wrong with those with this condition). I hope this way of thinking and behaving will shift as more research is conducted on this condition. This blog post results from many hurting voices crying out for help. There will be no rest for us until there is change. Thank you for listening.
For more information on Functional Neurological Disorder, please go to:
References
Bouhassira, D. (2019). Neuropathic pain: Definition, assessment, and epidemiology. Revue Neurologique, 175(1-2), 16-25. https://doi.org/10.1016/j.neurol.2018.09.016
Comruk, E. B., Buyukavci, R., Comruk, E., Akturk, S., & Ersoy, Y. (2023). Neuropathic pain in patients with post-COVID-19. Northern Clinics of Istanbul, 10(3), 359-366. https://doi.org/10.14744/nci.2022.31932
Mason, I., Renee, J., Marples, I., McWhirter, L., Carson, A., Stone, J., & Hoeritzauer, I. (2023). Functional neurological disorder is common in patients attending chronic pain clinics. European Journal of Neurology, 30(9). https://doi.org/10.1111/ene.15892
Mitsikostas, D.-D., Moka, E., Orrillo, E., Aurilio, C., Vadalouca, A., Paladini, A., & Varrassi, G. (2022). Cureus, 14(2), e22419. https://doi.org/10.7759/cureus.22419
Pun, P., Frater, J., Broughton, M., Dob, R., & Lehn, A. (2020). Psychological profiles and clinical clusters of patients diagnosed with Functional Neurological Disorder. Frontiers in Neurology, 11. https://doi.org/10.3389/fneur.2020.580267
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