Endometriosis and Nerves
The destinies of those affected by endometriosis are intricately entwined with the function of nerves. What may sound dramatic is often a practical reality. Nerves play a vital role in the body’s intricate communication network. However, their significance extends beyond transmitting messages; they can also be pivotal to endometriosis treatment. When undergoing surgery, handling these delicate components with care becomes particularly crucial to avoid any potential collateral damage. In this discussion, I will elucidate why nerves are a sensitive focal point in endometriosis and how they can enhance overall well-being.
What Is the Nervous System?
You may have heard yourself saying, “This is getting on my nerves.” Interestingly, nerves are intricately intertwined with our emotional experiences. The nervous system encompasses the peripheral nervous system, which functions like a complex network of roads throughout your body, and the central nervous system, situated in the brain and spinal cord. This intricate network facilitates interactions with the environment and supports many bodily functions. Your body executes familiar responses through sensory stimuli, such as muscle movements, enabling you to perceive pain. This pain sensation is a crucial protective mechanism that shields your body from harm. The nervous system is remarkable, housing several billion nerve cells known as neurons [1]. I will explore the connection between nerves and endometriosis in the following discussion.
Good to Know!
Good to Know!
Preserving the nervous system’s integrity is paramount as it oversees the intricate processes within your body. Nerve damage can give rise to various issues, including pain, mobility difficulties, and loss of sensation, among other complications. The proper functioning of organs like the bladder and intestines can also be compromised in the event of nerve damage.
Nerves and Endometriosis-Associated Pain
Pain is a sensation that arises when your brain receives pain signals, serving as an alert to potential harm or danger. Nociceptors, specialized pain-sensing receptors, are distributed throughout your body’s tissues and become active in response to various stimuli, including mechanical (e.g., pressure), thermal (e.g., extreme heat or cold), or chemical (e.g., inflammatory substances) triggers that are perceived as harmful. This activation can result from accidentally touching a hot stove or releasing inflammatory substances during inflammation. Nociceptors then transmit corresponding signals to your brain, culminating in the experience of pain and your awareness of it [2]. This fundamental process is also implicated in endometriosis-related pain, where the root cause of pain is often the presence of endometriosis lesions.
Nerves can play a role in supporting endometriosis therapy.
Pain, a prevalent symptom of endometriosis, can manifest primarily during menstruation but also independently, and it is a significant source of distress. It is important to note that pain is a highly subjective experience, with each perceiving it differently. Interestingly, studies have suggested potential gender differences in pain perception attributed to hormone variations and immune system variations between men and women [3]. However, to confirm this thesis unequivocally, further investigations must be made.
In addition to the nervous system, hormonal and immune systems can also influence pain perception. Inflammatory processes, for instance, can intensify the pain signal perceived by cells, prompting them to convey information about a more substantial issue to the brain, thereby amplifying the pain stimulus.
Furthermore, there are specialized nerve cells that function to inhibit the transmission of pain signals to the brain. These cells can diminish the strength of the signal sent to the brain, reducing pain perception. The nervous system plays a pivotal role in the experience of pain. This is where transcutaneous electrical nerve stimulation (TENS) comes into play.
TENS devices are designed to disrupt the transmission of pain signals to the brain, relieving individuals with endometriosis. Research has shown promising results for TENS units in alleviating the pain associated with conditions such as painful menstruation, which is common in endometriosis [4].
Why Distraction Helps Alleviate Pain:
Before you become consciously aware of pain experienced by pain-sensing cells, it must pass through the diencephalon, a region akin to a diligent secretary or a doorkeeper. This neutral gatekeeper sifts through incoming signals, allowing only the most vital information to reach the cerebrum, where you consciously perceive it. This phenomenon also clarifies why distraction techniques are affective in managing pain.
Endometriosis and Its Impact on Nerves
Nerves are intricately distributed throughout your body, making them susceptible to the effects of endometriosis. Some patients, for instance, experience leg pain, although it is not a typical symptom of endometriosis; however, it can occur when the growth affects pelvic nerves. Specifically, we refer to the sciatic nerve or sacral roots in this context. The sciatic nerve may have drawn your attention with its sharp, radiating pain extending from the lower back through the buttocks and down to the foot. This type of pain is often attributed not to endometriosis but to factors like overexertion or other unrelated causes. Nonetheless, in rare instances, physicians may encounter deep infiltrating endometriosis that poses a potential risk to the sciatic nerve. [6] Endometriosis growths can exert pressure on the nerve or even enter it. It is worth noting that the sciatic nerve is the longest and thickest nerve in your body, running from the lower back down through the buttocks and legs into the foot.
Within the small pelvis, you will find a set of 5 sacral roots, with the oldest three being particularly susceptible to endometriosis-related effects. Endometriosis tends to exhibit less aggressive behavior in these cases, typically enveloping the nerves rather than causing outright damage [4].
You can find more information on this critical subject in our Leg Pain in Endometriosis article.
Nerve Supply to Endometriosis Tissue
As an individual living with endometriosis, you have likely come across terms like “endometriosis tissue,” “endometriosis lesions,” or “endometriosis growths.” You might have wondered about the composition of these troublesome formations. Here is the reassuring news: endometriosis tissue is benign, so it should not be equated with cancerous growths. Its closer examination reveals that it closely resembles the tissue found in the uterus. From a biological standpoint, these growths consist of glands, smooth muscle, and stromal cells. Like any other bodily tissue, this organic mass requires nourishment, supplied through lymphatic vessels and blood vessels. Additionally, nerves play a role in the brain’s information transmission and retrieval [7, 8, 9, 10]. Consequently, nerves extend into these endometriosis formations. Physicians often call this process neurogenesis, during which nerve cells originate from stem or precursor cells. A similar process occurs with blood vessels, known as angiogenesis, as they grow to nourish the endometriosis tissue.
In summary, endometriosis has the potential to affect nerves, but they are also intricately connected and facilitate their growth into these foci by releasing growth factors.
The strong connection of endometriosis formations to the nervous system can intensify the transmission of pain signals, and in this context, more nerve cells may equate to heightened pain perception.
Good to Know!
The German Society for Gynecology and Obstetrics guideline program highlights transcutaneous electrical nerve stimulation as a viable treatment option within the ‘further therapy options’ section [5].
Takeaway Insights
Here is a fascinating scientific discovery: A unique study has shed light on how endometriosis impacts nerve fibers. Particularly intriguing is a critical substance in the peritoneal fluid of endometriosis patients – ‘nerve growth factor (NGF),’ a critical factor for nerve growth. While NGF was also detected in women without endometriosis, those with the condition had significantly higher levels. In a controlled experiment outside the body, researchers observed that nerve fibers began to grow when exposed to the peritoneal fluid of endometriosis patients, likely due to the influence of NGF. Substances inhibiting NGF could be explored for future treatments [10].
Nurturing Nerves
According to the guideline program of the German Society of Gynecology and Obstetrics for the diagnosis and therapy of endometriosis, various treatment options are available for endometriosis. Hormonal treatment, with progestogens like Dienogest as a first-line choice, plays a crucial role [11]. Simply put, the female sex hormone estrogen promotes endometriosis, while progesterone inhibits it. Progestin, a synthetic version of progesterone, has been extensively studied. This drug was found to reduce endometriosis lesions and hinder the formation of new nerves in the affected areas [12]. Surgery may also be necessary to remove the lesions. However, a nerve-sparing approach must be adopted when dealing with deep infiltrating endometriosis, especially concerning significant nerves influencing organ functions, such as the sciatic nerve, to minimize the risk of bladder dysfunction [13].
Therefore, if there is suspicion of nerve involvement, opting for surgery at a specialized endometriosis center or with a neuropelveologist is crucial.
In a Nutshell
Nerves play a pivotal role in the context of endometriosis. They are involved in transmitting pain signals exacerbating endometriosis-related pain. Yet, this pain can be alleviated through the TENS procedure, which interrupts the transmission of pain signals to the brain. Moreover, nerves serve crucial functions beyond endometriosis lesions, governing organ control and information gathering. Endometriosis lesions can also affect these nerves, leading to symptoms like numbness. Alongside blood and lymph vessels, nerves are integral to the supply of endometriosis lesions, forming precisely for this purpose (neurogenesis). In addition to hormonal treatment, surgical intervention is an option for managing endometriosis. Your physician should carefully consider the choice between treatments, taking into account the location of nerves in affected areas. Gentle removal of growths, especially in cases of deep infiltrating endometriosis, is paramount. Hence, the experience of the surgeon is vital!
References
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- Nozizeptives System amboss.com
- North RY, Li Y, Ray P, Rhines LD, Tatsui CE, Rao G, Johansson CA, Zhang H, Kim YH, Zhang B, Dussor G, Kim TH, Price TJ, Dougherty PM. Electrophysiological and transcriptomic correlates of neuropathic pain in human dorsal root ganglion neurons. Brain. 2019 May 1;142(5):1215-1226. doi: 10.1093/brain/awz063. PMID: 30887021; PMCID: PMC6487328.
- Bai HY, Bai HY, Yang ZQ. Effect of transcutaneous electrical nerve stimulation therapy for the treatment of primary dysmenorrheal. Medicine (Baltimore). 2017 Sep;96(36):e7959. doi: 10.1097/MD.0000000000007959. PMID: 28885348; PMCID: PMC6392990.
- Prof. Dr. med. Marc Possover: Die Endometriose des Ischias-Nervs und der Sakralwurzeln
- Leyendecker G, Herbertz M, Kunz G, Mall G. Endometriosis results from the dislocation of basal endometrium. Hum Reprod. 2002 Oct;17(10):2725-36. doi: 10.1093/humrep/17.10.2725. PMID: 12351554.
- Mechsner S, Bartley J, Loddenkemper C, Salomon DS, Starzinski-Powitz A, Ebert AD. Oxytocin receptor expression in smooth muscle cells of peritoneal endometriotic lesions and ovarian endometriotic cysts. Fertil Steril. 2005 Apr;83 Suppl 1:1220-31. doi: 10.1016/j.fertnstert.2004.11.038. PMID: 15831296.
- Bulun SE. Endometriosis. N Engl J Med. 2009 Jan 15;360(3):268-79. doi: 10.1056/NEJMra0804690. PMID: 19144942.
- Mechsner S, Schwarz J, Thode J, Loddenkemper C, Salomon DS, Ebert AD. Growth-associated protein 43-positive sensory nerve fibers accompanied by immature vessels are located in or near peritoneal endometriotic lesions. Fertil Steril. 2007 Sep;88(3):581-7. doi: 10.1016/j.fertnstert.2006.12.087. Epub 2007 Apr 6. PMID: 17412328.
- Barcena de Arellano ML, Arnold J, Vercellino F, Chiantera V, Schneider A, Mechsner S. Overexpression of nerve growth factor in peritoneal fluid from women with endometriosis may promote neurite outgrowth in endometriotic lesions. Fertil Steril. 2011 Mar 1;95(3):1123-6. doi: 10.1016/j.fertnstert.2010.10.023. Epub 2010 Nov 3. PMID: 21047631.
- Deutsche Gesellschaft für Gynäkologie und Geburtshilfe: Leitlinienprogramm. Diagnostik und Therapie der Endometriose. August 2020.
- Ferrero S, Remorgida V, Venturini PL, Bizzarri N. Endometriosis: the effects of dienogest. BMJ Clin Evid. 2015 Jun 9;2015:0802. PMID: 26057101; PMCID: PMC4461025.
- de Resende JA Júnior, Cavalini LT, Crispi CP, de Freitas Fonseca M. Risk of urinary retention after nerve-sparing surgery for deep infiltrating endometriosis: A systematic review and meta-analysis. Neurourol Urodyn. 2017 Jan;36(1):57-61. doi: 10.1002/nau.22915. Epub 2015 Oct 19. PMID: 26479158.
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