Medical Tuesday Blog
A Review Of Local And Regional Medical Journals And Articles
Allan Bernstein, MD
Pain is an essential part of our survival mechanism. It warns us that we stepped on a nail or that the coffee is too hot. It triggers autonomic responses that adjust our blood pressure, heart rate, pupillary reactions, blood sugar and blood cortisol levels. It is a warning to get our hand away from the flame and that our shoe is too tight. Pain is something we learn from. We’d like to avoid it, but we need it.
Pain typically indicates injury or potential injury, starting with tissue damage, releasing cytokines, stimulating peripheral nerves, and progressing proximally through nerve roots, spinal cord and into the brain. Spinal reflexes to pain allow us to pull our hand away from a painful stimulus before it even registers in our brain. A series of on/off switches along the way, particularly in the spinal cord and brainstem, allow us to modulate the pain and interpret the meaning. The endpoint, after multiple connections, is the frontal cortex, where we can localize the pain and decide how significant it is.
There are learned behaviors in our reaction to pain and genetic differences as to how we rate pain. “Big boys don’t cry” and “crybaby” are terms used in some cultures but not others. When I was studying painful neuropathy, using a 100-point pain scale, some subjects rated their pain at 80 while others claimed 20 for what appeared (to me) to be similar pain. After treatment, the 80s went to 70 and the 20s went to 17, a statistically identical percentage of reduction. Did one group feel more pain, or were they culturally sensitive when describing pain?
Anticipating pain will activate pain receptors and the appropriate autonomic responses. In contrast, anticipating pain relief will reduce pain signals, at least transiently. Nocebo responses (expecting something bad to happen) and placebo responses (expecting and getting benefit no matter what the treatment) may confound our research studies, but they can be turned into powerful clinical tools. The 45% placebo response in pain research tells us how much anticipation of relief affects our perception of pain.
The brain can create pain that isn’t there, such as phantom limb pain, and override significant pain when circumstances are appropriate, such as war injuries. Chronic pain–pain that persists in spite of no new tissue damage–represents a failure of the normal system that modulates pain.
Suffering is an individual’s emotional response to pain. It is not related to the intensity of the pain, but rather to fear, frustration and lack of understanding as to the meaning of the pain. If the etiology of the pain is well understood, one can rationalize severe pain as due to a specific injury, with an anticipated endpoint. Comprehension may not reduce pain, but it can moderate suffering for many people. The language we use to describe unpleasant situations often hints at a lack of control. We “suffer in silence,” “suffer the consequences” and “suffer the loss of a loved one.” These situations do not describe physiologic pain, but the emotional part of the pain–suffering–is the prominent feature that appears out of our control.
Both pain and suffering are difficult to measure. Pain fibers can be monitored in experimental animals. We assume pain is present when autonomic features appear in correspondence to the level of electrical impulses along pain pathways. We can measure endorphins and serotonin in spinal fluid. While both increase in response to acute pain, they both go down in chronic pain. As we gradually lose our ability to modulate pain, our suffering rises. Raising the level of endorphins and serotonin–through medications, spinal stimulators, exercise, cognitive therapy and diets–may improve pain control and relieve suffering. Therapies such as music, dance, painting and other pleasurable activities also reduce pain and suffering. Dopamine stimulation appears to be the physiologic pathway . . .
Read the entire article at Sonoma Medicine . . .
Dr. Bernstein, a Sebastopol neurologist, serves on the SCMA Editorial Board.
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