One of the mysteries of IC are the many related conditions that patients can suffer from. At first glance, IC, pelvic floor dysfunction, irritable bowel syndrome and vulvodynia share a strong commonality, location. All are disorders that occur in the pelvis. You wouldn’t expect to see a dental condition on the list, right? Yet, surprisingly, temporomandibular disorders (commonly known as TMD or TMJ) are also quite common in the IC patient. Ever wonder why?
I first developed TMD about five years into my diagnosis of IC. One morning I woke up with a partially dislocated jaw. After my jaw popped back into place, I could barely open my mouth. A specialist in jaw disorders confirmed that I had developed TMJ. I had all the signs.. a very tight neck, ringing in my ears, pain in my right jaw joint, a clicking sound when opening my mouth. My mus- cles at the joint were so tight that I had to massage them from inside my mouth.
What is TMD?
TMD is a group of conditions that cause pain and dysfunction of the jaw and the muscles that control jaw movement. Symptoms can include a dull, aching pain at the jaw joints, jaw muscles (including inside the mouth), the neck and shoulders. Muscles can become quite stiff, caus- ing very limited movement or locking of the jaw. Patients often feel a painful clicking, popping or grating in the jaw joint when opening and closing their mouth. Patients can also suffer with chronic headaches, ear pain, pressure and ringing and dizziness.
For most people, the cause is unknown and the discomfort is temporary, often occurring in cycles or flares. The pain eventually goes away with little or no treatment though some people can develop significant, long-term symptoms.
In their quest to unravel the mystery of TMD, researchers made a very important discovery. An estimated 85% of TMD patients also struggle with painful conditions in other parts of their body, including: chronic fatigue syndrome (CFS), vulvodynia, endometriosis, fibromyalgia, interstitial cystitis, irritable bowel syndrome, migraine and chronic pelvic pain.1 Stunned, they were the first to ask “Could some of these patients have a systemic disorder which could effect different organs?” Their work has now changed the face of chronic pain research and could lead, ultimately, to new therapies that will combat chronic pain.
Chronic Overlapping Pain Conditions (COPCs)
After seven national meetings con- ducted by the TMJ Association and the National Institutes of Health, as well as universal support from researchers, a new term is being used to describe patients who struggle with multiple chronic pain condi- tions – Chronic Overlapping Pain Conditions (COPCs). They argue that rather than considering each condition as separate and distinct, that this is one universal disorder with multiple presentations. It may include altered neural, immune and/or endocrine mechanisms which result in enhanced pain perception.
It merges beautifully with the new IC/BPS subtyping proposal by Dr. Christopher Payne in 2015.2 His subtypes are designed to direct patients and their providers to the most effective treatments for their unique presentation of IC.
IC Subtype 1 – Hunner’s Lesions
BPS Subtype 2 – Bladder Wall Driven
BPS Subtype 3 – Pelvic Floor Driven
BPS Subtype 4 – Pudendal Neuralgia
BPS Subtype 5 – Functional Somatic Syndrome/Central Sensitization Syndrome
Hunner’s lesions, IC Subtype 1, are treated with cauterization (laser or fulguration), steroid injection and/or the promising new LiRIS medical device currently in clinical trials.
BPS Subtype 2, Bladder Wall Driven, usually begins after a direct bladder insult such as: chemotherapy, infection, chemical exposure, ketamine use and even long term irritation from poor diet choices (i.e. coffees, sodas, etc.). Treatment priority is focused on calming and soothing the bladder, as well as to promote healing of the bladder wall.
BPS Subtype 3, Pelvic Floor Driven, frequently occurs after pelvic floor insult, such as: having a baby, a fall, traumatic accidents or perhaps even a rape. Therapy is usually first focused on restoring proper muscle tension with pelvic floor therapy and trigger point release.
BPS Subtype 4, Pudendal Neuralgia, occurs when the pudendal nerve has been impacted directly, usually by tight pelvic floor muscles or, in some cases, injury. Treatments are focused on releasing the nerve through physical therapy as well, if necessary, therapies to reduce nerve irritation and dysfunction.
It’s BPS Subtype 5, Central Sensitization Syndrome, that correlates with TMJ and the chronic pain community. These patients have a history of related pain conditions as well as signs of a very sensitive nervous system, including sensitive skin, drug sensitivity, food sensitivity, chemical sensitivity, heightened smell, sound and visual sensitivity.
Treatment is generally focused on calming and soothing the nervous system. We asked Dr. Ken Peters how he works with IC patients who have FSS/CSS. He said “I consider this a hypersensitivity disorder. Everything is sensitive, including the bowel, skin, vulva, etc. In these patients, their nerv- ous system is ‘wound up’ and our job is to unwind it. We try to identify every pain trigger and then work to reduce them.”3
He treats patients carefully, offering “The worst thing you can do is something aggressive and/or invasive that could ‘wind up’ their nervous system and cause more pain….In these complex patients, we must think outside the bladder and identify and chip away at all the pain triggers.”
The Chronic Pain Research Alliance
The TMJ Association created the Chronic Pain Research Alliance to bring together researchers and patient advocates from the IC/BPS, TMJ, vulvodynia, chronic fatigue syndrome, IBS, fibromyalgia, endometriosis, migraine headache and chronic low back pain commu- nities. In a 2015 white paper (available free online), they provide an in- depth discussion of possible disease mechanisms with extensive research citations and support.4
Multiple studies have found that some genetic variations can determine the sensitivity of a patients nervous system to pain as well as their risk for developing chronic pain. Studies have also identified that genetic variations can also influence pain and sensory processing. Not surprisingly, there is a strong genetic condition in some families with IC and other pain conditions.
Infection, trauma, injury or surgery may trigger the onset of COPCs.
Abnormal Pain & Sensory Processing
Patients with COPCs struggle with increased pain intensity with lower sensory and pain thresholds. In the bladder, we see this as greater pain even when the bladder contains very little fluid or is empty. Heightened sensitivity to light, sound and odors are also biologically applied in patients with COPC and that the insula, an area of the brain involved in sensory integration, shows hyperactivity. Studies have also shown that some patients experience a “wind up” in which painful stimulation causes increased pain perception which clearly indicates sensitization of the central nervous system.
How the brain processes pain has been studied with neural imaging techniques. With painful stimulation, brain regions that integrate and process sensory information, cognition and affect, show increased activity. COPC patients show distinct changes in various brain regions, including the size and shape of the cortical and subcortical areas. Studies have also found that these can reverse following treatment.
Central Nervous System Vs. Peripheral Nervous System
The peripheral nervous system delivers pain messages to the central nervous system. One theory is that the PNS afferent pathways become unregulated perhaps by injury or infection. When symptoms become more moderate or severe, the Central Nervous System pain processing is disinhibited which results in a lack of pain inhibition in the PNS. There are still many questions here.
With COPCs predominantly occurring in females, the role of hormones must be explored, especially given the fact that many conditions cyclically worsen during the menstrual cycle. IC is well known to flare the week before menstruation. These hormones can influence pain severity, pain thresholds and tolerance. Studies have shown that ovarian hormones affect inflammation, stress, modulatory pain systems and afferent sensory systems.
Neuroendocrine & Neuroimmune Abnormalities
COPC studies have found that immune-inflammatory mediators in the bloodstream and painful periph- eral tissues are altered and play a role in the development and/or chronicity of conditions in a subgroup of patients. There may also be changes in hypothalamic-pituitary-adrenal gland function which controls stress, immunity, digestion, emotion and energy storage. HPA dysregulation may play a role in a subset of patients with COPC’s.
Role of Stress, Behavior and Psychological Factors
The role of adverse childhood experiences, stress, behavioral and psychological factors clearly play a role in chronic illnesses (i.e. diabetes, heart disease and cancer.) When stress occurs as a result of chronic pain, patients may find it more diffi- cult to function in their daily lives, which can then undermine their con-