19 Aug 2019

Understanding chronic pain

From Afternoons with Jesse Mulligan, 2:31 pm on 19 August 2019

We all know what pain means to us specifically - but what actually is it and how can we deal with?

Dr Tipu Aamir, a pain medicine specialist for the Auckland Regional Pain Service, tells Jesse Mulligan about the differences between acute and chronic pain and treatments.

Dr Aamir says pain can be a good thing – it warns us of danger, protects us and helps in healing by restricting body movement in areas where there’s injury.

And chronic and acute aren’t terminologies used in relation to the severity of pain, rather the length or time, and the mechanism behind it, he says.

Dr Tipu Aamir

Dr Tipu Aamir Photo: RNZ / Karen Brown

“Acute pain is any pain which lasts for less than three months, it doesn’t really matter what starts the pain. It can be an injury, or an infection, and sometimes it can happen spontaneously, but any pain which lasts over three months or six months, depending on which definition we take, that pain is chronic.

“From a functional point of view, acute pain is a helpful phenomena, it helps us survive. While chronic pain is actually not performing any purpose. It is a pathological pain which has become a disease in its own right and it is actually … more of a hindrance in somebody’s life.”

Also different is the pathophysiological mechanism which maintains the two pains, he says.

But how pain is felt differs from person to person because it’s a subjective experience. It depends an a variety of factors, including genetics, gender or sex, mental state at the time of pain, and cultural background.

“For example, we know that chronic pain is much more common in females, and that’s an epidemiological fact that more females than males have back pain and migraines and abdominal pain,” Dr Aamir says.

“The research has shown that women can report slightly higher levels of pain and scientists have looked at it and what they’re saying is that part of the problem is probably the way that the female nervous system is modulating pain.”

Another common factor in those who experience pain is that it tends to strike people in their mid-30s and onwards, Dr Aamir says, and some end up losing their jobs as a result.

“This is the time where all of us are going to have worked hard, and we’re at the prime earning potential and we’re paying mortgages and we have kids. At that time when we lose our jobs, it’s going to have a significant financial impact that will lead to … significant financial stress, which is not uncommon for us to see.

“People start losing friends… Over a period of time, their life starts to shrink and they become more and more isolated. It’s not uncommon that people start to feel irritable and depressed.”

He says statistics show that more than 50 percent of people with chronic pain have been diagnosed with depression, or are in that category, and a similar number of people also report anxiety-related problems.

“It’s a downward spiral when it starts and it takes momentum.”

However, treatment of chronic pain has become more difficult with the limitations of medicine. With acute pain, people tend to take painkillers, apply any bandages if necessary and rest, but with chronic pain that’s not effective, Dr Aamir says.

“Those strategies work very well when we have acute pain but once the pain sticks around for months and years, it starts to have an impact life, because people are using the same strategies.

“Most people who come and see us … they are hoping to get a medicine … we don’t have the pharmaceutical agents at the moment which can change them or modulate [chronic pain mechanisms].”

One problem with using painkillers to treat chronic pain is that it will have to be over a longer duration than normal which poses health risks, including liver and kidney damage and heart problems, he says.

And more potent drugs like codeine, tramadol, morphine and oxycontin, may cause a significant set of side effects, including dependence and tolerance, he says.

“The drugs we do tend to use for chronic pain is the ones which modulate pain and those drugs are low-dose antidepressants, which are very, very old style, or we use some anti-epileptic medicine. But the problem with those drugs is their side effects can be very limiting and they’re not very effective.”

While some people may point to cannabis for chronic pain relief, Dr Aamir says that at the moment there’s “no good evidence” to show that it would be effective.

He says research has shown that only one in 24 people will experience a 30 percent reduction in pain when using cannabis. In comparison, he says one in about six or seven people will say there’s a 30 percent reduction in pain with a drug like gabapentin or pregabalin.

He says at their practice they take a social-psycho-biomedical approach with patients and assess them in an interdisciplinary manner. In that assessment, they spend about three hours with the patient, that includes talking to a pain specialist, a psychologist or a psychiatrist and a physiotherapist.

“We try to customise what we recommend … there are people who might need a trial of medication but there’s a big group of people whom we invite to attend our different programmes which we run.”

One important aspect in treatment of chronic pain, he says, is acceptance of the condition.

“When I talk about acceptance, what I mean by that is not acceptance that I have pain and can’t do anything about it. Acceptance means yes we have a problem, it’s a very difficult problem, however we need to do something to make our life better.”