Data Science

What is chronic pain 051017


  • Published10 May 2017

  • Reviewed10 May 2017

  • Source
    BrainFacts/SfN

What is chronic pain?

When you burn your hand or stub your toe, information about what’s happening in the body travels to the brain by way of sensory nerves that extend from the spinal cord out to the surfaces of the body. These nerves are specialized to detect various sensations—warmth, light touch, vibration, and so on. Some sensory nerve cells, called nociceptors, are specialized to detect noxious stimuli—those that can harm our tissues, such as a hot surface or blunt force.

For most people, pain resolves once an injury heals. But for some people, pain lasts long after the physical damage is repaired, sounding an alarm for a danger that is no longer present – this is called chronic pain.

Chronic pain affects more than 100 million Americans—more than cancer, heart disease and diabetes combined, and costs an estimated $600 billion per year. Chronic pain can be severely disabling, but many people are able to manage their pain and remain functional. Yet the condition—or rather the many conditions that fall under the umbrella of chronic pain—remains mysterious, even to doctors.

Chronic pain has many diverse causes. “Neuropathic pain” is caused by damage to nerves from physical injury, chemotherapy drugs, diabetes or shingles, and can cause nerves to “fire” inappropriately. Other people mysteriously develop back or neck pain or headaches without any explanation. And still others are stricken by fibromyalgia syndrome, which causes all-over body pain and serious fatigue, but its cause is yet unknown.

How do doctors test for and diagnose chronic pain? Is there a way to compare the severity of different types of pain?

When a bone is broken, an X-ray reveals the fracture; when cancer cells invade, a biopsy identifies them; genetic diseases can be detected with DNA sequencing. But one of the most challenging aspects of understanding and treating chronic pain is that there is no physical, objective test of pain. Doctors must rely on what the patient tells them about their pain, or what we call “patient self-reporting.”

Doctors often ask patients to report their pain on a scale of zero to ten, with zero being no pain and ten being the worst pain imaginable. But pain is not simply a physical sensation; it is a complex, whole-brain experience that is as unique as each individual. Some people might feel an intense physical sensation of pain, but they are able to cope with it, whereas others might experience extreme fear or anxiety in response to a lesser sensation. Doctors are increasingly aware that a patient’s pain level is what they say it is. Without an objective test, a patient’s word is final.

There are some sophisticated tests that can detect nerve or tissue damage that might cause pain. For example, a magnetic resonance imaging (MRI) scan of the spine could reveal potentially painful abnormalities. But these tests can be misleading because one patient with a normal-looking MRI might be experiencing excruciating pain, whereas another with a scan indicating a painful condition may not be bothered by pain.

How is chronic pain treated? Are there any new treatments on the horizon?

Because pain is such an individual experience, treatment, too, needs to be customized to the specific case. Unfortunately, there is no “magic bullet” to treat pain. Instead, doctors are left with a handful of medications that help some people — with serious risks.

The most commonly used medications to treat pain are called opioids, a class of drugs derived from the opium poppy that includes morphine and heroin, as well as the widely prescribed Oxycontin. The drugs mimic endogenous opioids, our brains’ own pain-dulling chemicals.

The US is in the grip of an opioid epidemic, and chronic pain is a major driving force behind the problem. Anyone taking opioids will build tolerance, requiring that they take more of the drug over time to achieve the same pain relief. Everyone taking opioids for more than a couple of weeks will become dependent, meaning that stopping the drugs will produce physical withdrawals. Nevertheless, for some people with chronic pain, long-term use of opioids can help them manage their pain and stay active.

Core Concepts

Researchers are always learning more about chronic pain.

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There are some promising new drugs in the pipeline, but it remains unclear how effective they will be, and for whom. More and more, doctors and patients are turning to complementary and integrative therapies as valuable tools for treating chronic pain. Rather than an “alternative” to medications, non-drug interventions should be used as part of a multi-pronged treatment plan. Evidence supports the use of yoga, acupuncture, mindfulness, and biofeedback for various pain conditions. Exercise in some cases can also help keep pain in check. The best treatment depends on the patient.

Because chronic pain is such a complex phenomenon that involves so many aspects of life, experts suggest that patients and clinicians consider the biopsychosocial influences on pain. For example, does the patient have support from family and friends; are they able to care for themselves daily; are they financially secure? Anxiety plays a huge role in chronic pain. Education is critical, and it can actually reduce pain. Patients should know that pain is real, it’s a physiological process that takes place in the brain, and it’s not their fault. This understanding can help reduce anxiety, which in turn lessens pain.

 

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