Julie Christianson, PhD, is an assistant professor at the University of Kansas Medical Center in Kansas City, Missouri. Christianson is a pain researcher whose lab is exploring the role that stress plays in chronic pelvic pain. She recently spoke by phone with freelance writer Allison Marin to discuss the causes and treatment of chronic pelvic pain, her latest research, and the questions that remain for researchers to answer. Below is an edited transcript of their conversation.
What is chronic pelvic pain and how is it diagnosed?
Chronic pelvic pain is not in itself a disease; rather it’s the main symptom and chief complaint from patients diagnosed with functional chronic pelvic pain disorders. These include irritable bowel syndrome (IBS), interstitial cystitis, vulvodynia, and chronic prostatitis.
Diagnosis of each of these syndromes is primarily symptom-based, depending on self-reported pain and disruptive symptomology from the patient, rather than based on a blood test or biopsy that shows a specific diagnosis. Generally, pelvic pain is considered to be chronic when it lasts for three months.
For females, especially with vulvodynia, the pain has to be noncyclical, meaning it can’t follow the menstrual cycle, so chronic pelvic pain is different from having really painful periods (dysmenorrhea). Most of these syndromes also have a functional component arising from the organ associated with the pain. With IBS, for example, patients suffer from diarrhea and/or constipation in addition to pelvic pain.
What are the symptoms and causes of each of these disorders?
IBS is a condition that primarily affects the functioning of the colon, and is associated with pain in the lower abdomen, which usually improves with defecation. Patients typically have either a diarrhea-prominent or constipation-predominant form. It’s quite prevalent—about 20% of the U.S. population is estimated to be affected by IBS—making it the most commonly diagnosed of the chronic pelvic pain syndromes. Like most of these disorders, it’s more commonly diagnosed in women; about twice as many women have IBS as men.
Interstitial cystitis is less common; it’s found in about 11% of women and 5% of men in the U.S. It is associated with an increased frequency of urination (as many as 50 times a day), pain in the bladder, and pain in the pelvic region. Sometimes ulcerations are present in the bladder, but not in all cases.
Two of these disorders affect the reproductive tract and are therefore sex-specific. Vulvodynia pain comes in different forms, but the most common is a burning or stinging pain in the vulva, termed vulvar vestibulitis. Unlike IBS or interstitial cystitis, the pain associated with vulvar vestibulitis can be provoked or constant and is found in about 4% of females. Chronic prostatitis, characterized by pain in the genitals and urinary tract, is the number one urological diagnosis for men under the age of 50, and the third for men over the age of 50. Over the course of their lifetime about 14% of men will be diagnosed with it.
As I mentioned before, these functional pain disorders are symptomatically diagnosed and have no pathology associated with them, making it difficult for doctors and scientists to understand exactly what is causing the pain and associated functional symptoms. However, it is widely accepted that disrupted communication between the immune system and the nervous system contributes to the development and maintenance of these syndromes. How and why this happens, and how to stop it, is the main focus of ongoing research on these syndromes.
Is there a relationship between these syndromes, and with other pain conditions?
Being diagnosed with a chronic pelvic pain syndrome makes a person more likely to suffer from another one. For example, if you have IBS, you are more likely to have interstitial cystitis, and, if you are a woman, more likely to have vulvodynia. Particularly in chronic prostatitis and interstitial cystitis, the symptoms are so similar that many times the physician won’t know which is the primary diagnosis and which is the secondary syndrome. In addition, having chronic pelvic pain makes a person more likely to have other widespread functional pain disorders, such as migraine and fibromyalgia, and more than half will also suffer from a psychological disorder, such as depression, anxiety, or panic disorder.
There aren’t many treatments that completely relieve chronic pelvic pain. What treatments are available, and why is it so difficult to treat?
The lack of pathology or disease in the affected organ(s) complicates the process for finding an appropriate treatment for most patients. For IBS, there are different medications such as antispasmodics and antiepileptic drugs that mainly treat the functional symptoms like constipation and diarrhea. Some severe vulvodynia patients will undergo surgery to excise the affected tissue. While this can be an effective treatment, it is a pretty severe step to take and illustrates just how negatively these syndromes can affect quality of life.
For the pain itself, especially in the case of vulvodynia and chronic prostatitis, the standard treatment is nonsteroidal anti-inflammatory drugs. For vulvodynia, topical analgesics like lidocaine can be applied locally. Physical therapy can also improve painful muscle spasms that are associated with some of these syndromes.
Treating an accompanying psychological disorder is also an important part of improving chronic pelvic pain, so all of these syndromes are commonly treated with certain kinds of antidepressants as well as cognitive behavioral therapy.
All of these treatments seem to be somewhat effective, but complete relief is often not possible. One reason that chronic pelvic pain is so difficult to treat is that two patients might have the same symptoms but not the same underlying cause, and so you can’t effectively treat them in the same way. For example, a patient with IBS that develops after an infection and a patient with IBS and no history of infection may present with the same symptoms, but they have developed under very different circumstances and may not respond to the same treatment regimen.
Many studies have shown that chronic pain is more likely to occur in people who experience stress early in life, and your research focuses on how stress contributes to chronic pelvic pain disorders in particular. What work are you doing in this area?
If people experience stress early in their life, it increases the likelihood that they will be diagnosed with a chronic pelvic pain syndrome later on. Likewise, patients diagnosed with chronic pelvic pain are more likely to have had some sort of stressor early in life. Examples of early life stress are parental loss or divorce, growing up in poverty, witnessing crime or drug abuse in the home, childhood physical or mental abuse, and even being born prematurely.
These stressors can change the way the body responds to stress later in life. When patients are under a lot of stress they will often report that their pelvic pain syndrome symptoms get worse. Or those whose symptoms may have been under control find that they come roaring back when they are under a lot of stress.
We are using animal models to understand the impact of early life stress on chronic pelvic pain. One example is a neonatal maternal separation model of early life stress. We separate newborn mice from their mothers, for three hours a day for their first three weeks of life, and then allow them to grow up normally. When we assess them as adults we find that they have an increased sensitivity to pain and altered function in their urogenital organs (the vagina, bladder, and prostate gland), similar to what is observed in humans with interstitial cystitis, vulvodynia, and chronic prostatitis.
What else have you found?
Similar to chronic pelvic pain patients, these mice also show signs of depression-like behaviors and have increased activation of mast cells (which are immune cells that are activated by the body’s stress response), in the tissues that are more sensitive to pain. When mast cells become activated, they can cause the nerves right next to them to become more sensitive and more likely to transmit pain signals.
One thing that is starting to show a lot of promise and that we’re certainly interested in is using exercise as a therapeutic intervention. Increasing exercise has been shown to improve the psychological disorders that accompany chronic pain in people and it’s widely known as a great stress reducer. When we let our mice run on a wheel after undergoing maternal separation, they don’t develop the urogenital sensitivity that we see in sedentary (non-exercising) animals. We believe that the main effect of exercise is occurring within the brain, specifically in an area called the hippocampus. This area of the brain is important for keeping the body’s response to stress under control. Early life stress exposure can decrease the ability of the hippocampus to control stress, while exercise has been shown to increase its influence on dampening the stress response. We believe that incorporating exercise can help reverse some of the negative effects caused by early life stress exposure in our mice.
What are some of the biggest questions about pelvic pain that researchers still need to answer?
What we really need is a way to classify patients that suffer from these different syndromes so that they can be properly treated. Stress is certainly one causative factor, but not all patients that have these disorders experienced stress early in life.
For example, if you have a patient that has vulvodynia but not any other syndromes, they might just need topical lidocaine. But another patient who has co-occuring vulvodynia, depression, interstitial cystitis, and fibromyalgia probably wouldn’t respond very well to that same treatment. They might need cognitive behavioral therapy, exercise, and an antidepressant. Even though they both suffer from vulvodynia, the underlying cause of their vaginal/vulvar pain is likely vastly different, and so they are each going to need a different set of tools to help control their pain. We really need to take a full symptomatic inventory of each individual patient so that the appropriate treatments are being used on an individual basis, rather than treating everyone the same.
About Irritable Bowel Syndrome (from the The International Foundation for Functional Gastrointestinal Disorders)
The Interstitial Cystitis Association
National Vulvodynia Association