This was published 8 years ago
Complex Regional Pain Syndrome: CPRS researchers study auditory connection
By John Elder
For 16 years, Kerry Whyman secretly thought she had bone cancer and was dying – "secretly" because she'd stopped telling doctors how much pain she was in.
"I'd wake up and my ankles were swollen and bruised, like they were sprained," says Ms Whyman, 55. "The doctor would ask 'what have you done?' I'd say 'nothing.' He'd send me for ultrasounds and they'd come back normal ... I decided to shut up because I felt I looked stupid."
Kerry Whyman suffers from complex regional pain syndrome, which makes her highly sensitive to noise.Credit: Paul Jeffers
If the pain wasn't in her ankles, it was somewhere else, sometimes in her organs. It seemed to move around Whyman's body at will. And it became more intense when she was exposed to noise. "My television is turned down to the lowest volume possible, and it's still too loud."
She got by all those years on paracetamol, anti-inflammatories and lot of drinking.
One day in 2008 Whyman met a woman with the same symptoms. The woman told Whyman that she was suffering Complex Regional Pain Syndrome, a rare and baffling condition that was first described during the American Civil War – and until 10 years ago was routinely dismissed as a psychiatric disorder.
"When I asked my GP if I had CRPS, he said he'd never heard of it. He thought I had carpal tunnel syndrome. But tests showed I didn't."
A neurologist finally confirmed CRPS. It most likely began when Whyman fell and fractured her right wrist 23 years ago. In most cases, Complex Regional Pain Syndrome is an ongoing consequence of a fractured limb – the broken bones heal, but the pain lingers, wanders randomly, and is aggravated by changes in weather, stress and noise.
Since the diagnosis, Whyman has been on "a merry-go-round" of treatments, most of them not working. The only thing that has given Whyman relief has been intravenous injections of ketamine, the hallucinatory anaesthetic.
Three times a year she is admitted to hospital for a week, and kept on an intravenous drip. She's knocked around but the pain goes away. Except in September, her most recent hospitalisation – it didn't work. She's resisting suggestions to undergo direct stimulation of the spine.
"They say I'm a perfect candidate, but surgery has to be the last resort," she says.
Depending on the research, there are between five and 25 new cases of Complex Regional Pain Syndrome per 100,000 every year. The actual prevalence is much higher because people, like Whyman, suffer for years.
About one in 10 people with a fracture go on to develop some form of the pain syndrome, says Professor Peter Drummond, a psychologist at Murdoch University, one of the few people doing research into the causes.
The Australian & New Zealand College of Anaesthetists is funding a study by Professor Drummond and Adjunct Professor Philip Finch, a pain medicine specialist, to unravel some of the complexity. They have together been researching various aspects of CRPS for 25 years.
A recent study found there is an increased number of alpha-1 adrenoceptors on skin cells and nerves in the damaged limb of Complex Regional Pain Syndrome patients. These receptors are involved in the stimulation of the sympathetic nervous system, which controls the "fight or flight" response. It may be that pain nerves are being over-stimulated. The researchers are further exploring this discovery.
"We're not sure why these receptors are over-expressed," says Drummond. "It seems to be a product of injury to the nerve itself or the inflammatory process. We're studying that in cell cultures, to work out what the stimulus it might be."
The new project is looking at the idea that the brain, in failing to adequately suppress pain, distorts normal sensory processing in the syndrome.
In a world first, Drummond and Finch will study the interaction between the auditory and pain-processing systems in CRPS patients. They plan to measure brain stem activity as the left and right ears of patients and a healthy control group are subjected to various noises. They are guessing that noises heard on the injured side of patients – reportedly are distorted and painful – will generate wave forms in the brain different to those generated by the auditory system on the healthy side.
Drummond and Finch expect they will be disentangling Complex Regional Pain Syndrome for many years to come.