Life Without Pain

One in five of us suffers from chronic pain. But breakthroughs in medical research are bringing hope for a pain-free future.

A Modern Chronicler of hell might look to the lives of chronic-pain patients for inspiration. Theirs is a special suffering - it's dimensions materialising at the Tuff's New England Medical Centre Pain Clinic in Boston. Here, in a small examining room, only three things exist: the doctor, the patient and pain. Of course, pain predominates.

"Chronic pain is like water damage to a house," sighs Dr Daniel Carr, the clinic's medical director. "If it goes on long enough, the house collapses. By the time most patients make their way to a pain clinic, it's very late."

What doctors see in a chronic-pain patient is a ruined body and a ruined life. It is Carr's job to rescue the crushed person within, to locate the original source of pain and to rebuild physically, psychologically and socially.

Chronic pain- continuos pain lasting longer than three months - afflicts hundreds of millions of people world-wide. Up to one in five suffer form it. While the emotional and physical toll is obvious, there is also a huge financial burden. For back problems alone, the financial cost to the Australian health system is over $700 million.

Only in recent years, however, has chronic pain become a focus of research. "It's a field on the verge of an explosion, " Carr says.

Pain had always been understood as a symptom of underlying disease: treat the illness, and the pain takes care of itself. Yet chronic pain often outlives its original cause, worsens over time and takes on a puzzling life of its own.

Research into "neural plasticity" - the capacity of neurons to change their function - has begun to shed light on what happens. Unlike ordinary or acute pain, which is part of a healthy nervous system, chronic pain resembles a disease, a pathology of the nervous system that produces abnormal changes in the brain and spinal cord. Far from being an unpleasant experience, endured simply with a stiff upper lip, this pain harms the body, unleashing negative hormones like cortisol that adversely affect the immune system and kidney function.

Disseminating new knowledge about pain will be difficult, however. Pain treatment resides primarily in the hands of ordinary physicians, most of whom know little about it. Only a small percentage are certified as pain specialists, and medical schools give the subject little attention.

Experiencing Pain

Daniel Carr is one of the world's leading pain specialists. A day spent in his clinic demonstrates the dangers of the wait-it-out approach to pain. A typical patient is Lee Burke, 56, who learned nearly a decade ago that she had an acoustic neuroma, a survivable brain tumour, behind her left ear. After surgery to remove the growth, the recovery was supposed to be seven weeks. Instead, Burke woke with headaches - lancinating, lightning-hot pain -that knocked her out for periods ranging from four hours to four days.

She never returned to her job as an executive at a real-estate company. When pain came between her and her husband, she left him - and her home. "it was easier to be alone with the pain, " she explains.

Asked to describe the headaches, Burke says, "It's like being slammed into a wall and totally destroyed." She looks at Carr with the stricken bewilderment seen on the effaces of many pain patients.

While Burke wipes her face, Carr sits calmly, hands in lap, his concentration fixed. He asks Burke to close her eye and taps her head with the corner of an unopened alcohol wipe. Within a few minutes, he has found a clear pattern of numbness, suggesting the occipital nerve in her face was severed or damaged during surgery. Burke's voice is small as she asks: "If the nerve was cut, why does it cause pain?"

It's a question researchers have only recently been able to answer. Doctors used to be so confident that severed nerves could not transmit pain - after all, they're severed - so nerve cutting was commonly prescribed as treatment. But while these nerves may stay dead, sometimes they grow back or fire spontaneously to produce stabbing, electrical or shooting sensations.

When Nerves Misfire

Picture the Pain Wiring of the nervous system as a warning device that protects the body form tissue injury or disease. Acute pain is like a properly working alarm system: the pain matches the damage and it disappears when the problem does. However, chronic pain is like a broken alarm: a wire is cut or hurt and the entire system goes haywire.

"The repair doesn't occur because the system itself is damaged," explains Dr Clifford Woolf, a pain researcher at Massachusetts General Hospital in Boston.

So why does chronic pain often worsen? Woolf's research has demonstrated that physical pain changes the body in the same way emotional loss watermarks the soul. The body's pain system is plastic, meaning it can be moulded by pain to cause more pain. Nerves recruit others in a "chronic-pain windup." The nervous system revs up and undergoes what Woolf calls "central sensitisation."

As for Burke's neuropathic pain, Carr prescribes Neurontin, an antiseizure drug that also acts as a nerve stabiliser and can quieten misfiring nerves. Within four months, Burke feels 50 per cent better. She can move her head side to side and sit up to watch TV instead of lying in agony. "Dr Carr is my saviour, " she says.

The Case for Tough Treatment

But why did it take seven years for Burke to get relief? "There's tremendous ignorance about neuropathic pain, " says Woolf. "Most doctors don't know to look for it." One confusing factor: not all patients with similar conditions develop chronic pain. Physicians might look at a patient's MRI scan and say, "The bone's all healed, " and conclude there is no reason for pain. But the pain is not in the muscles or bones - it is in the invisible hydra of the nerves.

Such confusion is what caused the delay in successfully treating Burke. Before coming to the clinic she had consulted Dr Martin Acquadro, a caring and competent physician. Observing, the severe muscle spasms in her head, neck and shoulders, Acquadro diagnosed tension headaches and treated Burke with Botox injections, tricyclic antidepressants and migraine medications.

Burke also tried range-of-motion physical therapy, stress-reduction courses, psychiatric treatment, yoga and meditation. She took 1600 milligrams of ibuprofen a day, along with 12 cups of coffee - caffeine is a treatment for migraines.

Acquadro hadn't thought of Neurontin and he feared opiates. "When a patient is depressed or anxious, you're leery about narcotics, " he says. "I was being cautious."

Although only an estimated five per cent of chronic pain patients using opiates such as morphine are considered at risk of developing addictive behaviour, the drugs have a reputation for being dangerous.

The other problem is that women tend to be less aggressive in demanding pain treatment or can behave in ways misinterpreted as hysteria. The longer pain goes untreated, the more desperate the patient becomes - until those behaviours look like the problem. Whenever Acquadro sent Burke to specialists, she's break down in pain. "They figured I was a basket case, " she says. "And I was."

Link to Depression

In fact, almost everyone who has chronic pain eventually develops anxiety and depression. Surprisingly, pain and depression both share the same neural circuitry. The neurotransmitters and hormones modulating a healthy brain - such as serotonin and endorphins - are the same ones that control depression.

"Chronic pain uses up serotonin in the brain like a car running out of fuel," says a psychiatrist Dr William Breitbart. "If the pain persists long enough, everybody runs out of fuel."

Medications that treat depression also treat pain. Depression or stressful events can, in turn, enhance pain. But to make stress reduction a primary treatment is like trying to repaint walls in a crumbling house.

"Chronic pain is not just a sensory or affective or cognitive state, " says Woolf. "It's a biologic disease afflicting millions of people. However, soon I believe there will be effective treatment because the tools are coming together to understand and treat it."

The Future

The most important tool in Woolf's lab is the new "gene chip" technology that identifies which genes become active when neurons respond to pain. "In the past 30 years of pain research, we've looked for pain-related genes one at a time and come up with 60. In the past two years, using gene-chip technology, we've confirmed more than 1000, " says Woolf. "All we have to do is find the key genes, the master switches that drive the others.

Woolf is particularly interested in certain abnormal sodium ion channels seen only in damaged sensory neurons. He believes he's close - perhaps a year away - from identifying which of these channels are most important. Then, if the animal data applies to humans, pharmaceutical companies could design blockers for those channels and develop new drugs. The biggest question of pain research now is: will a blocker for neuropathic pain help all people who already have it?

Woolf hesitates, "We don't really know, " he says. But there is one thing he's confident about: that doctors will soon be able to stop pain before it becomes so debilitating.