I’ve got one nerve left and you’re standing on it!
I ask myself, how does something others find pleasant, like a cool breeze blowing over their body on a hot summer day, cause me such discomfort? How can my brain’s pathways and messengers be so dysfunctional? As it turns out, even though changes in the brain are visible on imaging, researchers don’t have answers either. There are no diagnostic criteria even though centralization of chronic pain is apparent.
- central nervous system (CNS) = the brain and spinal cord
- peripheral nervous system (PNS) = the nervous system outside the brain and spinal cord
Central sensitization, centralization of pain
Centralized pain syndromes, pain originating somewhere in the central nervous system, usually occur from some type of injury or disease within the brain or spinal cord. “Centralization of pain” or “central sensitization” results from cellular and molecular changes. These and other changes in the CNS result from abnormal pain signal processing between the peripheral nervous system (PNS) and the CNS.
For instance, messages from the PNS become distorted because of detours or derailments, and dysfunctional neuro-messengers. The message containing information on the content, character, and intensity of a problem leaves the periphery just fine, but it doesn’t reach the brain that way.
Why doesn’t centralization of pain occur in everyone?
In an interview with Dr. Hurst-Wicker (my pain doctor), he had this to say. “The transition from acute to chronic pain has a variety of contributing factors. Sometimes the underlying problem can’t be fixed, like a bad joint that can’t be replaced because the patient is too sick for surgery. In other cases, people with chronic pain can develop changes in the CNS that lead to central sensitization thus perpetuating pain even after the initial problem is fixed. Some studies indicate genetic factors may explain why some people experience chronic pain and others don’t. Other studies indicate certain pain medications could initiate the process of central sensitization. We don’t know why.”
Many factors are at play in chronic pain. The pathways, signals, and other influencers are not operating correctly, but the dysfunction isn’t the same for all chronic pain, and no two of us are alike. I expect neuroscientists, those who study how the nervous system develops, its structure, and what it does, will continue to seek answers to our questions, because current evidence is too compelling.
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Contributing factors to centralization of pain in fibromyalgia
Those of us with fibromyalgia know stress and dysfunctional sleep contribute to our pain levels. In part, that’s because we have abnormal stress hormone levels that amplify our pain. We also have abnormal sleep patterns that interrupt the circadian rhythm responsible for micro healing and restoration of our brain and body. And, imaging in one study found the size of the hippocampus is reduced in FM patients. That’s the part of our brain responsible for memory and spatial awareness.
This leads us to another study I found quite interesting to this equation. Galvez-Sánchez and others (2018) showed the pain experience during low intensity stimulation is more closely related to attention, memory and executive functions in those of us with FM. This evidence suggests central sensitization (abnormally amplified pain) influences our cognitive problems. I couldn’t agree more.
It remains unclear if all people with chronic pain experience altered cognitive processing because, unlike fibromyalgia, there aren’t any diagnostic criteria for chronic pain as a disease or syndrome.
Chronic pain usually results from injury or it can be triggered by hormonal or metabolic changes; however, some chronic pain doesn’t have an identifiable cause. Regardless, constant, unrelenting pain can cause structural and processing changes in our brain and/or spinal cord. I found a new imaging technique reported on in Stanford’s Scope Blog, The beating brain, quite interesting. One day it may be used to diagnose abnormal brain structure.
It’s important to remember that our brain also allows us to do things that we know reduces stress on our CNS. The impact of something as simple as deep breathing can have a profound effect. Ask any mother about the value of deep breathing in labor. Thanks to neuroimaging (2018) there is evidence that mindful exercises affect activity in a positive way. Our head is indeed a valuable piece of real estate in the state of pain.
Let’s raise awareness that chronic pain is more than subjective. Chronic pain is real, and everyone deserves access to treatments and medications without bias or recrimination. Share the evidence and your thoughts with your legislators and others. I have compiled resources in The Advocate’s Corner.
Celeste Cooper, RN, is a frequent contributor to ProHealth. She is an advocate, writer and published author, and a person living with chronic pain. Celeste is lead author of Integrative Therapies for Fibromyalgia, Chronic Fatigue Syndrome, and Myofascial Pain and Broken Body, Wounded Spirit, and Balancing the See Saw of Chronic Pain (a four-book series). She spends her time enjoying her family and the rewards she receives from interacting with nature through her writing and photography. You can learn more about Celeste’s writing, advocacy work, helpful tips, and social network connections at CelesteCooper.com.