December 2009: New Ideas about Chronic Pain and its Treatment
30 Nov 2009
Dr. Michael McNett is a board-certified pain management specialist at Weiss Memorial Hospital. His specialties include fibromyalgia, noninterventional pain management and addiction prevention.
Dr. Michael McNett
APAC Centers for Pain Management
Weiss Memorial Hospital
Pain is a large and growing problem in the United States. More than one-third of Americans suffer from some form of chronic pain, and more than 50 million are partially or completely disabled due to chronic pain. As the population ages, this number is expected to get even higher. Pain is also a major cause of a number of other problems, including sleep disorder, clinical depression or anxiety, hypertension, heart attack, stroke and intestinal bleeding. Studies have indicated that the risk of death by suicide is doubled in chronic pain patients.
Chronic pain leads to many misconceptions and false beliefs. Some people believe it is a result of inadequate discipline and self-control. Others think, “It’s all in your head.” Still others brand patients with chronic pain as drug-seeking addicts. Thankfully, modern research is shedding light on this difficult disorder.
Understanding chronic pain
There are two major components to chronic pain. First is the injury that caused it. Many things can cause pain, including a physical injury causing tissue destruction (such as a back injury), a nerve injury from a viral infection (such as shingles), a growing tissue causing pressure on a sensitive area (such as cancer), as well as numerous others. The key is that the injury causes a change in the body, resulting in the activation of pain nerves and, unless that injury heals or is treated, the pain will continue.
The second component occurs when the pain nerves are activated on an ongoing basis for some time. Nerves have two main functions: to communicate with each other (and with other tissues like muscles) and to learn. If a pain nerve has been activated for several days or weeks, it starts to “learn” that it is supposed to be active. (In technical terms, this is called “neuroplasticity.”) Changes occur in the nerve, which cause it to become activated; this may even reach the point where it discharges without any input at all. This is the cause of “phantom limb pain,” when a person can feel pain in their foot even after it has been amputated.
The best way to prevent a person from getting chronic pain is to rapidly and effectively treat the injury. For example, if a person hurts their back lifting, it is critical to get to treatment as soon as possible. If the pain nerves are prevented from activating by effective pain treatment (in this case, usually ice, brief rest, an anti-inflammatory like prescription-strength ibuprofen, a muscle relaxant and an analgesic like hydrocodone with acetaminophen), the “learning” process is much less likely to occur. Physical therapy can also help prevent muscle tightening, provide retraining and strengthening, and help the tissues heal more rapidly and normally.
But sometimes an ongoing disruption in the tissue requires more aggressive care. If a disc is ruptured in a back injury, research has shown that a number of inflammatory chemicals are released which consistently irritate the pain nerve, causing ongoing pain. In this case, more aggressive therapy is warranted. Typically, the next step if pain medications and physical therapy don’t work is to do an MRI to see if there is a ruptured disc. If so, a pain specialist can inject cortisone directly into the area of rupture. This provides a potent anti-inflammatory effect which can often quiet down the nerve and allow it to return to normal functioning, although in some cases up to three injections might be required. If this step does not help the pain, surgery might be required.
Medicinal options for pain relief
If the pain is severe enough and lasts long enough, even completely reversing the injury may not provide adequate relief of the pain. It is believed that many patients have had their pain nerves trained to be active (i.e., they have “learned” to be in pain). This is a common cause for why people may have pain after an injury even though there is no clear reason for having it.
In these cases, other types of medications may be required. A certain class of antidepressants (called serotonin-norepinephrine reuptake inhibitors) raises specific chemicals in the nervous system that inhibit the activity of pain nerves. It appears that we can inhibit our own pain nerves by activating inhibitory tracts in our nervous system that go from the brain down to the spinal cord and tell the pain nerves to be quiet. These antidepressants appear to make that process much stronger. As a result, they can reduce chronic pain – particularly “learned” pain.
Another group of medicines that help chronic pain are seizure drugs, or anticonvulsants. Several of these are commonly used in chronic pain because they have been found to “lower the volume” of the pain nerves coming in from the body by reducing the number of neurotransmitters they release.
Analgesics are another commonly used group of medicines for chronic pain, although their greatest benefit is for sudden-onset (“acute”) pain. While they certainly can have a role to play in chronic pain, they must be used with caution. Statistics show that about 4 percent of people receiving opiates are at high risk of becoming addicted to them. While that may seem like a small number, in the past decade prescription opiates have become the number one cause of drug abuse (not counting alcohol).
In addition, we have recently become aware of the extent to which opiates play a negative role in pain – in many cases, they cause a short-term improvement in pain while at the same time causing changes in the nerve that in the long run actually increase its pain sensitivity (called a “pro-nociceptive effect”). This causes the person to require higher and higher doses as the benefit wears off, until they may reach the point where no amount of opiate is effective.
Counseling and other methods of pain relief
The impact of mental attitude is important. Some people naturally understand how to shut off their pain sensations. Others are extremely sensitive to even mild injuries. This may be because they have not developed the mechanisms within their nervous systems that help quiet pain. Counseling called “cognitive behavioral therapy” helps patients learn how to harness these internal defenses by controlling attitudes, learning not to focus on the pain or not letting themselves fall into victimhood. This is often very helpful as a component of treatment.
Finally, a variety of other treatments may be indicated, such as heat, muscle relaxants, sleep medications, trigger point injections, acupuncture, etc. The need for these vary by the kind of pain experienced. Depression and anxiety are common and should be carefully watched. Physical therapy can play a very helpful role in strengthening, preventing limitation of range of motion and retraining muscles to maximize function.
In summary, our new understanding of how chronic pain develops has played a great role in teaching us how to provide better pain management. The best way to prevent chronic pain is to rapidly and effectively treat acute pain. If this isn’t possible, then effective management of chronic pain must be undertaken. This treatment may include cognitive behavioral therapy, physical therapy, anticonvulsants, SNRI antidepressants, carefully chosen analgesics and other medications as indicated. With proper care, many patients can adequately control chronic pain to regain an acceptable quality of life.
For more information
If you would like more information about treating chronic pain or would like an appointment, please call Dr. McNett’s office at (773) 564-5205.