Scientists are unraveling the mysteries of pain

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Our understanding of pain has evolved over the years. Especially following the west’s interest in surgical anesthesia w/ acupuncture when NY Times reporters accompanied President Nixon to China in 1968.

This summary in NatGeo does a great recap

❇️ How non-noxious stimuli can trigger pain in previously irritated areas.
“an unexpected finding. After a patch of skin subjected to heat a few times became inflamed, the neurons in the spinal cord attained a heightened state of sensitivity. Merely stroking the area surrounding the previously injured patch caused them to fire.

This showed that the injury to the skin had sensitized the central nervous system, causing neurons in the spinal cord to transmit pain signals to the brain even when the input from peripheral nerves was innocuous. Other researchers have since demonstrated this phenomenon—called central sensitization—in humans and shown that it drives various types of pain”

❇️ Pain isn’t necessarily an indication of current tissue threat or in the absence of injury a psycho-somatic or imagined feeling. Pain is always real.

“A startling conclusion from Woolf’s work and subsequent research was that pain could be generated in the absence of a triggering injury. This challenged the view held by some doctors that patients who complained of pain that couldn’t be explained by any obvious pathology were likely lying for one reason or another—to get painkillers they didn’t need, perhaps, or to gain sympathy. The pain transmission system can become hypersensitive in the wake of an injury—which is what happened in the rats—but it also can go haywire on its own or stay in a sensitized state well after an injury has healed. This is what happens in patients with neuropathic pain, fibromyalgia, irritable bowel syndrome, and certain other conditions. Their pain is not a symptom; it’s a disease—one caused by a malfunctioning nervous system.”

❇️ Pain is not only an input from tissue overload, damage, or injury but also an output of the brain. In other words you’re context & state of mind influence you’re pain.

“While scientists like Woolf are advancing the understanding of how pain is transmitted, other scientists have discovered that these signals are just one factor in how the brain perceives pain. Pain, it turns out, is a complex, subjective phenomenon that is shaped by the particular brain that’s experiencing it. How pain signals are ultimately translated into painful sensations can be influenced by a person’s emotional state. The context in which the pain is being perceived also can alter how it feels, as evidenced by the pleasantness of the aches that follow a strenuous workout or the desire for a second helping of a spicy dish despite the punishing sting it delivers to the tongue.
“You’ve got thisincredible capability of altering how those signals are processed when they do arrive,” says Irene Tracey, a neuroscientist at the University of Oxford. Tracey has spent much of her career trying to bridge the mysterious link between injury and pain. “This is a highly nonlinear relationship, and many things can make it worse or can make it better or could make it very different,” she says.

They also learned that the same stimulus doesn’t produce the same activation pattern every time, indicating that a person’s experience of pain can vary even when the injuries are similar. This flexibility serves us well, raising our pain tolerance in situations that demand it—for instance, when carrying a scorching bowl of soup from the microwave to the kitchen counter. The mind knows that dropping the bowl midway would result in greater misery than the brief anguish caused by holding the bowl, so it tolerates the momentary suffering.

Tracey and her colleagues have shown that fear, anxiety, and sadness can make pain feel worse.”

❇️ Many orthopedic surgeries aren’t necessary. Even when they work it can be because of the placebo effect.

“A recent British study of more than 300 patients with a type of shoulder pain thought to be caused by a bone spur. To relieve the pain, the spur is often removed in surgery. Researchers randomly divided the participants into three groups. One group underwent the surgery. A second group was led to believe it had, but it hadn’t. A third group was asked to return in three months to see a shoulder specialist. The group that had the operation and the one that thought it did reported similar relief from their shoulder pain.
“What it showed is that it’s just a placebo. The surgery is not mechanistically doing anything for the pain,” says Oxford’s Irene Tracey, one of the study’s authors. “The pain relief the patients are getting is just driven by a placebo effect.”
But to Tracey, the outcome isn’t any less important because it shows the placebo effect worked. On the contrary, she says, the study reveals the force of a patient’s belief in the treatment. “What it’s powerfully saying is expectations shape pain,” Tracey says.

a patient’s expectation of reduced pain can translate into actual relief. It seems to activate the brain’s descending pain pathway, leading to the release of opioids synthesized inside the brain that impede the incoming pain signals from the body.
“This is not just pretend,” Tracey says. “The placebo mechanism hijacks this very powerful system in the brain.”

❇️ Hurt is an alarm, but may not equal harm. Pain sensitivity & pain or activity tolerance are different. At LASS we aim to reassure you that most activity is good for pain. If you let pain run you’re life it often gets worse. We try to find how you can improve both you’re physical capacity to protect painful areas more & put you’re mind at ease that you’re tissues while sensitive aren’t necessarily fragile. Sustainable participation in activities you value is our goal.

“In several patients, we saw an improvement in their quality of life, in their sensation of well-being, in their independence—without improving the amount of pain,” Machado says. Patients who had scored their pain as a nine on a 10-point scale, for example, continued to give it the same score but reported being able to function better. One of the study subjects, Linda Grubb, describes the treatment as transformative. “It made all the difference in the world as far as being able to go places,” she says, adding that her post-stroke pain had compelled her to spend her days on the couch. “I have so much more energy. My husband says I seem so much happier. It really changed my life completely.”…/scientists-are-unrave…/


Scientists are unraveling the mysteries of pain

With the opioid crisis, the quest to understand the biology of pain and explore new ways to treat it has taken on fresh urgency.

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Posted to FB on 2020-01-07 18:12:00

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