Sunday, October 2, 2011

The burden of no proof

Because there is no objective way to measure chronic pain, people who suffer from it often struggle to convince others that their pain is real.
Kurt Gengenbach is a C4 quadriplegic that suffers from chronic pain. Gengenbach is photographed in his Toronto, Ont., home, July 27, 2011.

Kurt Gengenbach is a C4 quadriplegic that suffers from chronic pain. Gengenbach is photographed in his Toronto, Ont., home, July 27, 2011.

Three months after breaking the fourth cervical vertebra in his neck in a freak hockey accident at the age of 17, Kurt Gengenbach began experiencing a new and spectacular kind of torment.
He started feeling pain in his left pectoral muscle - a constant burning, pins-andneedles sensation that slowly spread to his right shoulder, across his chest, down into his abdomen and finally through his legs and into his feet.
Gengenbach is a quadriplegic. He cannot move his arms or his legs. But he can feel pain. His ankles feel as if they're bound in thick, bonecrushing casts. A Kleenex against his bare shoulder can feel like a blowtorch. The skin on his chest is so hypersensitive he can't breathe deeply to relax when the pain hits, the way his therapist told him to, because expanding his chest makes his skin stretch, and it's torture. "Basically I'm paralysed by pain," he says.
The tragic irony - that a body that can't even move is still racked by continuing pain - is compounded, Gengenbach says, by the fact that sometimes people don't believe him.
Some of his attendants know that just moving his arm or touching him can be painful. "Others think, 'It can't hurt him that much,' and they just kind of throw me around," the Toronto resident says. "They don't believe it."
Canadian researchers are trying to stamp out once and for all the skepticism faced by many who suffer severe, persistent pain. The revolution in research Canadians are helping to lead is aimed at showing just how real pain is.
Researchers are using hightech imaging to show the human brain in the act of processing pain.
They're discovering how unrelenting, day-in and dayout pain can change the brain's anatomy (pain shrinks the brain in some areas) and how those abnormal changes can be reversed with successful treatment. They're discovering just how often poorly treated pain after surgery morphs into chronic pain that can last for years.
In Quebec, 3,500 patients are being followed in what is believed to be the largest registry of chronic-pain patients in the world - a massive undertaking that could unlock answers to one of the most universal of all human experiences, including what factors predispose us to chronic pain, and what perpetuates it.
The goal across this research spectrum is to reduce suffering and banish the idea that pain that doesn't respond to treatment - or that seems wholly out of sync with any physical finding - isn't genuine.
"There is a huge social change that is happening," says Dr. Fernando Cervero, director of the Alan Edwards Centre for Research on Pain at McGill University, one of the world's leading pain research centres. "We are in a way leading, but also society is leading it. People are saying, 'Why do we have to live with pain?' "
Scientists have long been searching for an objective way to measure pain - using heart rate, blood pressure, temperature changes, muscle tension, and skin sweating. These physiological "markers" can work for short, sharp pain, but not chronic pain.
Now, researchers are taking the first steps toward developing a tool to detect pain based on patterns of human brain activity. The most recent experiments involve functional MRIs. Normal MRIs take pictures of the structure of the brain; fMRIs take a series of pictures showing what activity is going on.
In a study reported last month, Stanford University School of Medicine researchers put people inside the brain-scanning machines, applied a heat probe to their arms, then looked at the brain patterns with and without heat.
The brain patterns were recorded and interpreted by computer algorithms to create a model of what pain - in this case, mild pain in a carefully controlled lab setting - looks like.
The next step is to see whether the same method can be used to measure chronic pain.
"The issue of validation of pain is a critical one," said senior author Dr. Sean Mackey, chief of the division of pain management at Stanford.
"They don't feel like they've been believed, they feel as if their physicians and friends and families think the pain is not real. They're desperately looking for a way to prove to people that they do have pain."
Mackey said he would like to think this technology isn't needed, that doctors could and should be educated that pain is real, that it's a "neurophysiologic phenomenon" - that it is whatever the patient says it is.
In fact, chronic pain conditions are among the most devastating diseases known to man. For example, complex regional pain syndrome - nerve pain that can develop from trauma or surgery, and sometimes without any known trigger - can feel as though the finger ends are being ripped away from the bones.
Drugs used to treat chronic pain, when they work, provide some relief, but they're crude - they target not only pain receptors, but receptors throughout the body, meaning they affect virtually every bodily system, bringing sideeffects such as nausea, fatigue and memory loss. What's more, doctors aren't entirely sure what it is they should be targeting.
This much is known: Having pain that doesn't go away - pain so severe that it makes it impossible to work, to think, even to sleep - is to live in another world. Some people have quality-of-life scores that are equivalent to terminal cancer. "It's probably beyond your comprehension if you haven't experienced it," says Dr. Lori Montgomery, medical director of the Calgary Chronic Pain Centre.
In many cases, chronic pain is caused by a neural response to tissue damage. The nervous system is alive, and it can generate pain.
"Every level of the neuraxis, from the tips of the toes to the top of the brain, can be involved," says Dr. Mary Lynch, director of the Pain Management Unit at the Queen Elizabeth II Health Sciences Centre in Halifax.
In addition, our genes as well as our past experiences, mood and emotions can influence how we feel pain and respond to treatment.
For generations, the prevailing theory on how pain works was straightforward: In response to injury or disease, special pain receptors or nerve fibres in the skin, muscle, joints and other tissues act like a shrill alarm. The alarm sends pain signals through the spinal cord up into a pain centre in the cerebral cortex, where we were thought to "feel" pain.
"The metaphor we use is ringing the bell," Montgomery says. Pull the cord and the bell rings. That was the old model. More recent research tells us that pain is much more complex than we ever imagined, she says.
"There are many nerve pathways, and many different mechanisms that decide whether that alarm signal will make it to the brain or not."
Pain is a survival mechanism. Humans need to feel acute pain - sudden bursts of pain from an injury - in order for the species to thrive. Acute pain tells the brain something is wrong.
Chronic pain doesn't serve the same survival function. It can occur when the alarm gets stuck, even after the fire is out. The nerves keep shooting pain signals up to the brain, as if the tissues were still being damaged. The bell is ringing for no apparent reason, Montgomery says, "or there may be a reason, but we don't understand what it is."
Not only do the pain signals spontaneously fire, they'll now respond to stimuli, says Lynch. Things that shouldn't be harmful - even a light touch - can cause excruciating pain.
"Many patients will say, 'I can't stand to be touched anymore. I can't take a shower - the water on my neck and shoulders is just too painful.' They can't tolerate the feeling of the sheets on their feet at night," says Lynch.
"These are classic descriptions that we hear every day in pain clinics across the country."
But what happens when there is no physical explanation, no "organic basis" to account for the pain?
"You can take a picture of somebody's spine and it looks absolutely normal and perfect, and yet they have horrible pain. So where is the pain?" asks renowned pain researcher Dr. Ronald Melzack, professor emeritus of psychology at McGill University.
"That's the pain we need to start concentrating on."
Pain, he says, used to get three pages in the medical textbooks. Pain was a sensation, he says, "it didn't mean suffering." Nearly 40 years ago, Melzack helped put a language to pain with the McGill Pain Questionnaire, a tool now used the world over to assess pain. It consists of 78 pain descriptors - words such as pounding, drilling, quivering, stabbing, shooting, exhausting, sickening, suffocating - to try to describe suffering. Each is rated on a five-point scale - the higher the pain score, the greater the pain.
But it was his "gate control" theory of pain that revolutionized pain science.
In 1965, Melzack and his colleague, MIT neuroscientist Patrick Wall, published a theory that challenged the idea that there was a one-way, skin-to-brain "pain pathway."
Instead, their gate-control theory argued that nerve cells in the spinal cord act like miniature gates that can block pain signals from getting through and up into the brain, or allow them in.
Melzack once explained it this way: "If you are playing hockey and get kicked in the shin, your gates are often closed because your brain isn't interested in pain at that time." (Kurt Gengenbach once skated an entire game on a broken ankle. He didn't realize the bone was broken until he took his skate off.)
"On the other hand, " Melzack said, "if you have a slight stomach ache and you learn that a friend has just died of stomach cancer, suddenly the gates are opened, and you may have terrible abdominal pain."
Melzack has expanded his hypothesis since. He says humans are born with genetically determined neural networks, which are pain-processing programs in our brains that can be influenced by mood, emotions, memories and other sensory experiences.
This "neuromatrix" can be activated by an injury or illness, he says. But it can also go off spontaneously.
Amputees frequently report stabbing, burning searing pain in their phantom limbs. "How do you account for that?" Melzack says. "The only way you can is that the leg we feel is in our brain."
Experts say that how we think about pain can affect how we feel pain and, for some, the urge is to "catastrophize" the pain - "this pain will never go away, I will never be able to handle this."
Catastrophizing can stop people from taking action, says Michael Negraeff, a clinical associate professor in the department anesthesia at the University of British Columbia and chair of Pain BC. It also increases the amount of pain people report.
"You have to absolutely validate that they are having pain and that all pain is real," he says. "Only then can you begin to work on helping them see what is not helping them."
Attention can also have a significant impact on pain and pain processing, says Dr. Catherine Bushnell, professor of anesthesia at McGill University in Montreal and president of the Canadian Pain Society.
In studies of healthy volunteers who were subjected to experimental pain - heat not hot enough to cause a blister but hot enough to activate the person's pain system - Bushnell's team has found that people rate their pain higher when they're focusing on it. "When you're distracted, you feel less pain."
Emotions modulate pain differently, she says. When people experience positive emotions, "they still feel pain, they still rate it with the same intensity, but it bothers them less, it's less unpleasant," says Bushnell. "These are ways that you can engage in and work on your own therapy."
Some worry the new focus on the mind could make science slip back into seeing pain as purely psychological. Distraction works in a lab where a bit of pain is inflicted for a short time, and in real life when the pain is light, says Lous Heshusius, author of Inside Chronic Pain: An Intimate and Critical Account. But when pain is intense, distraction can make it worse, she says.
"That's why we often withdraw when severe pain strikes," she says. What people living with severe pain need is real purpose, she says. "Something that is still worthwhile living for."
For 12 years, Kurt Gengenbach watched helplessly as pain took over his body, as more and more parts started hurting.
Gengenbach, now 40, was paralysed during a senior high school hockey game, when he went in for a hit, lost the edge of his skate and slammed headfirst into the boards.
Today he suffers from neuropathic pain. With a spinal cord injury, sensory nerves at the level of the injury are also damaged, causing changes in their electrical signalling. Some of those damaged nerves get stuck in the "on" setting, so the pain signals keep firing.
Gengenbach has been living with pain for 22 years. "You don't get used to it, you just learn to deal with it," he says. The most difficult thing, he says, is frustration with people not understanding the pain.
He has a medicinal marijuana licence because marijuana helps control his pain by controlling muscle spasms. Yet some of his attendants refuse to hold his pipe for him, saying they have a right to work in a smoke-free environment. Gengenbach has disposable surgical masks that would cover their face entirely. He takes only one puff at a time from a small bowl pipe. The amount of smoke, he says, is minuscule.
At night, he sometimes lies awake in agony. He can see his pipe next to his bed when he turns his head, but he can't reach out and grab it. It's right there, right beside him. "I can see it. But I can't get it."
"I sometimes beg for the ability to make someone feel my pain for five or 10 seconds," he says. "I feel bad for saying that. . It's very hard for people to understand.
"My pain dictates my life much more than my disability ever has."
ABOUT THIS SERIES
Yesterday: Roughly six million Canadians live with chronic pain, yet despite the burden of suffering, pain is poorly treated in Canada, if it's treated at all.
Today: Canadian researchers are trying to stamp out once and for all the skepticism faced by many who suffer severe, persistent pain.
Tomorrow: Opioids have been shown to be effective for serious, intractable pain, but fears about addiction and abuse means people in pain continue to suffer.
Tuesday: Studies suggest intense and frequent pain affects about five to eight per cent of children and adolescents, but it too goes under-recognized and undertreated.
Watch a video of Maggie Bristow, who has fibromyalgia and spinal stenosis. The conditions that have left the former administrative assistant from Ottawa in so much pain there are days she questions whether she wants to go on.
Watch an interview with of Dr. Manon Choinière of the Quebec Pain Registry, which is following 3,500 chronicpain patients. The massive undertaking could unlock answers to what factors predispose us to chronic pain, and what perpetuates it.
Watch a video interview with Dr. Mark Ware, the director of clinical research at the Alan Edwards Pain Management Unit at the Montreal General Hospital.
Award-winning Postmedia journalist Sharon Kirkey has covered health for nearly 20 years. She spent three months talking to experts and people with chronic pain across the country to shed light on a condition that affects roughly six million Canadians, who are often left to suffer in silence.

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