Diagnosing pain

Our knowledge of pain is increasingly complex. We look at mainstream medical attitudes, and how biology and psychology fit into the science of chronic pain

In June 2014, Joan Young fell down a flight of steps.

The 50-year-old homemaker started to have pain on her upper back, shoulder, and weakness in her arms; she found that she had a tear in her cervical spine in her neck.

She didn’t know it then, until August, when the pain spread to her upper back, shoulder and arms.

The pain is constant. “Oh, I have it like 24/7,” she says, somewhat casually, at her home in Pasir Ris.

Young says that her high pain tolerance — from giving birth to four children — helped. “I think, for a lot of people, it would have affected them,” she says. “But my daily life, it continued; it bothered me a little bit, but not enough.”

Still, the pain was constantly there, even after a surgery to fix the tear in her cervical spine.

“I was supposed to be better,” Young says. “But I continued to have pain, which actually baffled my specialist.”

She was sent to a rheumatologist to find out if the pain was related to a dysfunction in her joints or connective tissue, and her spine specialist had to consult with other doctors before concluding that she had fibromyalgia — a condition characterised by chronic widespread pain and increased sensitivity to pressure.

The cause of fibromyalgia is still unknown, though scientists think that genetic and environmental causes — like mutations in genes dictating neurotransmitter systems and a lack of physical activity — may be involved.

While shuttling between specialists to look for a diagnosis could have been stressful for others, Young says she managed it well. “I was just taking it in my stride,” she says.

But the journey towards diagnosis and proper pain relief can be long.

Doctors usually try to find a source of chronic pain, in order to rule out what they term as “red flags”, like cancers, infections or fractures.

“Identifying red flags early is paramount because these conditions are treatable,” says Dr Ho Kok Yuen, clinical director of the pain management service at Raffles Hospital.

But if there is no source of pain, treatment would then switch to symptom control, like pain relief, Dr Ho adds.

For Evon Toh, a 36-year-old course coordinator at the National Institute of Education, a proper diagnosis on the cause of her lower back pain is still out of reach.

“When I went for an MRI, they checked and there was nothing wrong with my nerves,” Toh says.

She booked an appointment for a MRI scan in a private clinic, and her pain specialist said that there was no clear cause for her chronic pain, apart from the notion that her scoliosis — a curved spine — was “very bad”, and that the pain was likely caused in her muscles.

“It’s actually pretty depressing to always feel like I don’t know why I’m hurting,” she adds.

Toh’s experience isn’t unusual. “We treat a lot of patients where there is no ongoing cause for their pain, or their ongoing illness actually is not so severe, but the pain is much out of proportion to the illness,” says NUH’s Dr Tan.

Looking at the whole picture

The collective impact of biological, psychological and social — or biopsychosocial — factors mean that treatment of chronic pain thus involves a host of specialists.

“We work closely with physiotherapists, occupational therapists; the acupuncture clinic is just located here,” says Dr Tan. “When we assess patients, we look at the whole picture.”

At NUH, he uses the Brief Pain Inventory — a nine-item questionnaire — to evaluate the patient’s severity of pain and how pain will impact their daily life.

“(The Inventory) looks at how patients function, whether the pain affects their sleep, mood, walking, working, enjoyment, and things like that,” he adds. 

The hospital also uses the Hospital Anxiety and Depression Scale, another 14-item questionnaire to see if patients are suffering from anxiety and depression.

Other than its profound impact on a person’s psyche, pain also has biological links with depression, says Dr Tan.

Intense pain leads to brain activity that releases noradrenaline, a hormone involved in regulating the body’s response to stress, while serotonin, a hormone which contributes to the regulation of mood, appetite and sleep, has been shown to sensitize nerve fibres in cases of inflammation and nerve injury.

Tricyclic antidepressants, have been prescribed for neuropathic pain, as they inhibit reuptake of serotonin and noradrenaline. These antidepressants can also help sufferers with their sleep and mood.

“That is why the drugs which are used for depression, sometimes we use it for pain, and sometimes the drugs that we use for pain is also used for depression,” he says.

Studies have suggested that nearly half of chronic pain patients suffer from depressive disorders; a 1990 study of patients who were diagnosed with fibromyalgia found that almost half acknowledged some degree of anxiety, while nearly 70 percent of patients in a 1999 University of Washington study reported being angry.

Pain doctors in Singapore report similar issues. Nearly one-third of patients at Raffles Medicine have had psychiatric issues stemming from chronic pain, according to Dr Ho. Another 20 to 30 percent have also reported issues with mood.

At Tan Tock Seng Hospital’s (TTSH) pain management clinic, more than half of the patients have reported issues with mood, memory or sleep, while less than 25 percent have presented with psychiatric problems like depression.

“If you’re a patient, you just know you have pain,” says SIT’s Christopher Lo. Sufferers often want to find out why they have it and just want to recover, he adds. “After consultation, they might not find out what is wrong. We need to explain to them that there may be no abnormal structures in their body causing pain.”

The long-term effects of chronic pain may lead to sufferers feeling frustrated, as “they start to worry about whether it’s something that the doctors have missed,” says Dr Yang Su-yin, clinical lead for pain psychology at TTSH. “Many of them find that their whole lifestyle has to change because of pain.”

Young now avoids eating outside, for example, as she finds that monosodium glutamate (MSG) exacerbates her pain. When she goes on vacation, she calls ahead to restaurants to find out if they use MSG. “We don’t eat junk food, and we don’t eat fast food,” she says.

There is some evidence that increased concentrations of MSG could contribute to pain and sensitivity in certain musculoskeletal pain conditions, while four patients who eliminated additives like MSG or aspartame — an artificial sweetener — experienced pain relief, according to a 2001 study.

Aside from that, Young’s diet hasn’t changed much. “I eat anything, as long as I prepare it myself.”

Young does feel a bit handicapped because she can no longer carry heavy items. But that’s mostly it, she says. “I’m not very affected by a lot of things.”

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