The Peripheral Nervous System, Interstitial Cystitis, and Pelvic Pain

 

By Katie Hunter

 

I had the pleasure of attending Dr. Kenneth Peters’ lecture on the role of the Peripheral Nervous System(PNS) in the development and management of pelvic pain. Kenneth Peters, MD is a urologist practicing at Beaumont Hospital in Royal Oaks, MI, who specializes in treating complex pelvic pain including interstitial cystitis. For more information on Dr. Peters, check out his website here.

 

What is Interstitial Cystitis?

 

The first question Dr. Peters presents is how do we define “true” interstitial cystitis? Historically, the symptoms and diagnosis of interstitial cystitis have been classically defined by the presence of Hunner’s ulcers, most commonly seen in women, and described as pain in the bladder region at the anterior abdominal wall. In the 1943 Urology in General Practice textbook, there is a statement: “on behalf of women who complain of bladder trouble for which the average physician can find no cause, we plead that they not be condemned as neurotics until Hunner’s ulcers have been ruled out.”  Fast forward to 1970 in the “bible of urology” textbook [according to Dr. Peters], Campbell’s Urology, where Hunner’s ulcers are described as “confusing, poorly understood, baffling etiology” that makes “a thoughtful physician wonder about the possibility of a mildly masochistic woman, i.e. destructive need in the female to suffer and ‘have trouble with’ her genitourinary apparatus.” Who wrote this textbook, Donald Trump? Dr. Peters’ point being, [much like our political climate today] while this was 30 years later, their thoughts were archaic and outdated. Luckily today, we have researchers and clinicians disproving these thoughts and validating this syndrome.

 

For more on the history of IC and current AUA Guidelines for the treatment of IC, check out Stephanie’s blog here.

 

“Hunner’s Lesion is a different disease and we should look at it as a separate entity,” according to Dr. Peters. Hunner’s lesion-IC and bladder pain syndrome or painful bladder syndrome are clearly distinguished in this lecture.

 

 

Dr. Peters quips that IC has been an oversimplified diagnosis and “if a patient hurts between their belly button and their knees, they’re told they have IC.” By giving a patient this diagnosis, a physician is defining their pain as a “bladder disease” which is misleading and results in inaccurate treatment plans and numerous failed treatments. This causes more fear in the patient that their symptoms will never resolve and often leads to distrust in the provider. Fortunately, through past, present, and future research, more and more providers will start recognizing the bladder as “an innocent bystander” in this population of patients.

 

I was very pleased that Dr. Peters emphasized that up to 87% of patients with the diagnosis of IC have pelvic floor dysfunction (PFD) and that PFD is likely an underlying cause or component of their symptoms. Even more exciting, he shares that he has received a significant Grant from the Department of Defense to study bladder directed therapy vs. pelvic floor directed therapy. We have already seen in past research that pelvic floor directed therapy was more successful in treating symptoms of IC than a general body massage (for more details about this study, check out Shannon’s blog here); but, it will be enlightening to many providers to see if pelvic floor directed therapy is more successful than bladder directed therapy. We hope his research will further emphasize the lack of efficacy for bladder directed treatments on non-Hunner’s lesion IC and reduce the number of failed treatments and procedures our patients must endure.

 

Non-Hunner’s lesion IC has overlapping symptoms with overactive bladder, pudendal neuralgia, vulvodynia, and CPPS. Patients with all of these diagnoses often have urinary urgency, frequency, and painful sex. Deferentially diagnosing the source of the symptoms will lead to successful outcomes.

 

Why do these various diagnoses have similar symptoms?

 

To answer this question, we must first understand what causes persisting pain. One theme of #WCAAP17 was the neurophysiology of chronic pain. Dr. Peters summarizes the whole picture of persisting pain in the following way:

 

 

Associated disorders of chronic pelvic pain include pelvic floor dysfunction, IC, prostatitis, IBS, urinary retention/incontinence, chronic constipation, headache disorders, fibromyalgia, and depression. As many of these disorders affect an organ, they may be defined as visceral pain syndromes in which pain arises in one or many organs. With visceral pain syndrome and CPP, we see an ongoing feedback loop of tissue injury, nervous system upregulation, and neurogenic inflammation. As pain persists in one organ, it may cause inflammation in the surrounding area, signalling a neighboring organ to elicit a painful response and the feedback loop continues. This is why it is essential for clinicians to assess and treat the “whole person” and explains why a multimodal treatment approach is required.

 

 

How do we treat this ongoing neuropathic feedback loop?

 

In developing a treatment plan, the biggest question is what is the driver of the pain? We are often thinking to ourselves, “which came first, the chicken or the egg?” because there are so many possible causes for these types of symptoms. For chronic pelvic pain and visceral pain syndromes, the most important nerve contributions are, in the periphery, the hypogastric, pelvic, and pudendal nerves; in the CNS, the right dorsomedial pons, periaqueduct, hypothalamus, and inferior frontal gyrus. The standard of care at this time is to treat all mechanisms of pain including both the peripheral and central nervous systems as this will successfully interrupt the ongoing feedback loop.

 

Treating the Peripheral Nervous System

 

At the periphery, activation of our c-fibers leads to our perception of pain in the brain. Repetitive activation of these fibers causes the response of the fibers to go up. My classic example is if you burn your hand on the stove and the next time you get close to the heat, your body reacts in a much bigger way by pulling away before you even touch the flame. This is partly due to the fibers in these nerves being more responsive – to protect us.

 

The pudendal nerve is one of the biggest players in pelvic pain, sexual pain disorder and IC – no surprise for us there! After the patient meets criteria of a pudendal neuralgia/neuropathy component which is currently defined by Nantes criteria, you can use focused treatments like diagnostic/therapeutic pudendal nerve blocks, pelvic floor physical therapy, electrotherapy, and neuromodulation.  Electrotherapy can be used directly on a peripheral nerve that is suspected to be causing pain. This works to modulate impulses from the periphery and reduce pain signals to the brain. Neuromodulation can modulate impulses at all levels from the local nerve to the supraspinal level and cerebral cortex and “block” or “gate” the pain signal.

 

Treating the Central Nervous System

 

Due to a prolonged peripheral response to pain, our central nervous system starts to make changes and adaptations. This results in abnormal inhibitory reflexes, architectural changes in the spinal circuits and increased dendritic synapses, increased release of neurotransmitters, merging of the sensory and somatic nerve pathways, reduced filtration of sensory inputs, and an expansion of the sensory field. This explains why our patients with chronic pelvic pain will begin to feel pain when a non-painful stimulus is present; i.e. pain with touch, clothing, bladder filling, etc.

 

Neuromodulation is heavily supported by literature for treating chronic pelvic pain. While it affects the peripheral NS, it is also beneficial in treating these CNS adaptations. It does this by either re-balancing and normalizing our brain’s response or reducing the input to the brain. Neuromodulation may applied at either the sacral level (S3) of the spine or pudendal nerve which will affect S2, S3, and S4. This has been shown to reduce pain intensity and improve quality of life for patients with pelvic pain who did not have associated voiding dysfunction.

 

Alternative Pain Cycle

 

Dr. Peters also touches on an alternative pain cycle that many of our patients suffer from as their pain persists.

 

 

This picture is what we are often concerned with as physical therapists. This emphasizes and supports the importance of addressing the muscles of the pelvic floor. Dr. Peters even states that these muscles should be treated first! By reducing muscle spasms and improving blood flow to the pelvis, this will help the treatments targeted towards the nervous system to be more effective and efficient.

 

Lastly, he emphasizes the need for a multidisciplinary approach, incorporating complementary therapies such as pelvic floor physical therapy, cognitive behavioral therapy, guided imagery, dietary modifications, and yoga/meditation to address all of the components of pelvic pain.

We thank Dr. Peters for a wonderful lecture and for sharing his clinical research that is helping so many of our patients! To view the Powerpoint in its entirety please start on page 107 here.