Pain affects more than 116 million people in the United States every year. It is one of the leading causes of work disability and a main reason why people take medication. The public health significance of pain is so great that on Wednesday the Institute of Medicine will release a study, "Relieving Pain in America," that highlights the obstacles to effective pain prevention and treatment.
While most pain resolves once the injury or condition that caused it has healed, millions struggle with chronic pain, defined simply as pain that persists beyond the expected period of time.
Chronic pain can arise from injuries as well as from conditions as various as cancer, diabetic neuropathy, shingles, arthritis and fibromyalgia.
Chronic pain is a particularly debilitating condition because it tends to reinforce itself. Pain leads to feelings of anger, depression and social isolation, which in turn increase the perception of pain. Patients in pain exercise less, which leads to muscle loss, less range of movement and even more pain.
Chronic pain can also be especially challenging for doctors to treat, not only because it can arise from so many causes but also because it is difficult to measure and because patients' perceptions of pain can vary widely.
Doctors often ask patients to rate their pain on a zero-to-10 scale, with 1 being hardly noticeable and 10 being intolerable, but those assessments are from the patients themselves.
"Pain isn't like diabetes, where you can measure blood glucose," said Doris Cope, vice chairman of UPMC's Pain Medicine Program and professor of anesthesiology at the University of Pittsburgh. "It's a totally subjective measurement."
She added that many factors could influence a patient's perception of pain's severity, even experiences from their distant past.
"A patient with [post-traumatic stress disorder] or a traumatic childhood might say their pain is 20 out of 10," she said.
But while patients suffering from chronic pain might once have been dismissed by doctors, recent medical advances in understanding the mechanisms of pain have changed the way it is treated.
Physicians now understand that pain can involve many of the body's systems and that effective treatment can require coordination across multiple medical specialties, such as neurobiology, psychology, rehabilitation medicine and anesthesiology.
"So many things go into the chronic pain model, we have to think of the whole person," said Abraham Kabazie, director of the Institute for Pain Medicine at West Penn Hospital. "We're continuing to educate ourselves about the pain spectrum."
Pain medicine is a growing field, he said, pointing out that both West Penn's pain medicine program and Pitt's department of anesthesiology now have pain medicine fellowships, multidisciplinary programs open to doctors who have completed their residencies and want to focus on treating pain.
Greater understanding of pain has also resulted in an arsenal of newer treatments, many of which are becoming available in our area. These treatments include those based on traditional methods such as drugs and surgery and also less traditional ones, such as acupuncture, meditation and yoga.
Psychological counseling has also become an important part of treating chronic pain, allowing patients to cope with negative feelings and restrictions and stick with treatment regimens.
Pain treatment usually begins with over-the-counter medications, such as acetaminophen (for example, Tylenol) and ibuprofen (Advil, Motrin).
If these don't control the pain, a doctor may prescribe anticonvulsants, such as Lyrica and Neurontin. It's not known how these drugs, usually prescribed for seizure disorders, relieve chronic pain, but they can be especially helpful with pain originating in the nerves, like that from shingles.
A greater understanding of how neurotransmitters, the chemicals that convey messages between nerves, work to cause pain has led to a new class of drugs: antidepressants, usually at lower doses than those used to treat depression. Drugs approved for this use include Elavil and Cymbalta.
For even more serious pain, there are opiate-based narcotics, such as codeine, oxycodone and fentanyl. These are highly effective against severe, chronic pain, but they can be addictive, tend to become less effective over time and have unpleasant side effects such as severe drowsiness and constipation.
Drug manufacturers have tried to combat these disadvantages by inventing synthetic opiates and altering the drugs' delivery system. Dr. Kabazie said the FDA recently approved a skin patch sold as Butrans that delivers buprenorphine, a partly synthetic opioid, over a period of seven days. The patch allows for more constant, lower levels of medication that work even for patients who have developed a tolerance for other drugs.
But narcotics remain problematic. "These are important tools for treating pain," Dr. Cope said. "But these drugs are like selling guns. They are a controlled substance."
Prescription drugs are now a leading cause of death in the United States, she pointed out. By 2006, overdoses of opiate pain medication were already the cause of more deaths than cocaine and heroin combined, and those numbers continue to climb.
"People think these drugs are safe, because they're prescription," she added. "But they are just as powerful as any street drug."
Beyond medication, targeted procedures offer a wide range of options for those suffering chronic pain. Dr. Cope cited both intrathecal pumps and radiofrequency ablation as promising new treatments.
Intrathecal pumps, also called spinal drug pumps, must be implanted in the body, but they allow patients to deliver pain medication straight to the affected nerves by pushing a button. The medication then blocks the pain signal. They use lower levels of medication than when taken by mouth, and they offer patients a greater sense of control over their pain.
In radiofrequency ablation, a needle delivers an electric current in the range of radio waves, which heats and destroys painful nerve tissue. Although nerves do grow back, the procedure can offer three to six months of freedom from pain.
If other methods have failed to address a patient's chronic pain, Dr. Kabazie said, he will consider implanting a spinal cord stimulator.
Also known as pain pacemakers, these devices are implanted in the body, where they deliver a low-level electrical signal to the spinal cord, which blocks pain signals. Patients can turn the device on and off or adjust the level of the signal.
Often used for back pain, Dr. Kabazie cited a patient with chest wall scarring from surgery who found relief from the device.
"Spinal cord stimulators have been pigeonholed for certain types of pain, but I think they will work for multiple pain states," Dr. Kabazie said.
Alternative therapies for treating pain have also gained wider acceptance as evidence that they work has mounted.
"I see much more openness on the part of folks that think of themselves as traditional Western physicians to things like chiropractic and body work for people with back problems, for example," said Ronald Glick, director of the Center for Integrative Medicine at UPMC Shadyside since 2003.
Established in 2000, the center incorporates complementary therapies into patients' conventional treatment. While the center treats patients with conditions that range from incontinence to anxiety, many of its patients experience some kind of chronic pain.
Dr. Glick said the growing understanding of the mind-body connection in pain has led doctors to treat pain with therapies shown to reduce stress and anxiety, such as meditation, as well as with methods such as acupuncture, massage and yoga.
"Stress and depression, just by itself with no injury, raises all sorts of inflammatory markers for the body," he said. "There's no question that a person's state of mind affects their physical health."
He added that the center addresses three things in all of its patients, then combines them for the optimal approach for the individual.
"First, we help people look at tools for managing their stress. We also look at their diet, because the typical American diet boosts inflammation," he said. "Third is exercise. We help people find something they can do every day."
He said that although the therapies at the center might be considered alternative, it was important that there be evidence for their effectiveness.
"A big part of the center's mission is to test these therapies," he said. "We currently have several National Institutes of Health studies going on."
One ongoing study is "Aging Successfully With Pain," which is being conducted by Natalia Morone, an assistant professor of medicine at Pitt. It studies how "mindfulness-based stress reduction," a method with roots in meditation, can help adults 65 and older to manage chronic low back pain.
Although the study will continue for three years, Dr. Glick said initial findings are encouraging.
"These patients perceive someone caring about them and teaching them something useful, and it reduces their perceptions of pain and gives them a sense of control," he said.
Regardless of the methods they use to treat chronic pain, Dr. Glick and Dr. Kabazie agreed that patient commitment and involvement in their treatment led to better outcomes.
"Patients have to be motivated," Dr. Kabazie said. "Whether they're doing rehabilitation or doing yoga, they have to be committed."
"Mindset is important," Dr. Glick said. "With chronic pain patients, they may never be pain-free. But there's a lot they can do to manage their pain and improve their lives."
For more on UPMC's Pain Medicine Program, go to www.upmc.com/services/painmedicine/Pages/default.aspx.
For more on West Penn's Institute for Pain Medicine, go to http://wpahs.org/wph/services/index.cfm?mode=view&medicalspecialty=114.
For more information on the Center for Integrative Medicine, go to www.upmc.com/Services/integrative-medicine/Pages/default.aspx.
For information on how to enroll in the "Aging Successfully With Pain" study, call 412-586-9817.
Kate Luce Angell is a Pittsburgh-based freelance writer.