Complex Regional Pain Syndrome (CRPS) and Fibromyalgia

Young woman with incurable pain condition
A few years ago, Paige Howitt went into a routine surgery for her knee. Shortly afterward, she began feeling an intense pain radiating from the site of the surgery. As the weeks went by, the pain began to spread and grow more intense. Though she didn’t know it at the time, she was suffering from a condition called “complex regional pain syndrome (CRPS).”

CRPS is a rare condition that can affect people who have recently suffered some trauma to the body. In Paige’s case, it was surgery. But CRPS can also affect people who have had strokes, heart attacks, or serious injuries. We don’t know for certain what causes people like Paige to develop CRPS, but the answer probably lies in the nervous system.

Nerves are obviously very sensitive. And when exposed to trauma, they sometimes become hyperactive, sending pain signals to the brain that are far more intense than the original injury and can continue to do so long after the injury is healed. Think of it like a dial that controls pain being turned up and then getting stuck there.  As a result, people like Paige deal with constant, agonizing pain.

And like Paige, people with CRPS often find that the pain begins to control every aspect of their lives. Paige found that the pain was so intense she had to cut back her hours at work and can no longer do the types of things she used to enjoy. And because heat makes her pain worse, she can never be far from an ice pack.

Obviously, Paige’s story is familiar to anyone who suffers from the condition. But it’s also familiar to anyone who suffers from fibromyalgia. After all, anyone who has Fibromyalgia knows how chronic pain can completely change someone’s life. And the similarity between the two conditions has led some people to speculate that there may be a link between CRPS and fibromyalgia. But is there anything to that theory? Let’s take a look at some of the evidence.

CRPS and Fibromyalgia

There are some obvious similarities between CRPS and Fibromyalgia. Both cause pain with no obvious source. Both conditions can develop after physical trauma. And with each condition, the pain can be severe enough to be debilitating. People with either CRPS and Fibromyalgia often have difficulty moving, and the sites where the pain is located are usually sensitive to touch. And changes in temperature can aggravate both conditions.

But there are some significant differences as well. In cases of CRPS, the pain is usually located at the site of the injury. In Paige’s case, the pain is focused on the knee. That’s different from fibromyalgia, where the pain spreads across nearly the entire body, particularly in 18 specific tender points. In addition, CRPS often leads to swelling around the site of the original injury. And while people with fibromyalgia may experience swelling, it’s usually not as localized as in CRPS.

But in spite of the differences, there may be a significant connection between the two conditions. As with CRPS, the pain of fibromyalgia is probably rooted in the nervous system. Researchers in Australia have recently proposed a possible explanation for both conditions that could explain this connection.

Essentially, the idea is that inflammation in the nervous system causes the nerves to transmit pain signals to the brain. Once nerve cells are damaged, the immune system begins sending cells to the nerves to repair them. As the nerve cells heal, they become more sensitive in response to these immune cells. That’s why injuries can seem to grow more painful overtime before healing.

Usually, the nerve cells eventually stop being over sensitive and the pain goes away. But in cases of CRPS and fibromyalgia, the nerve cells may get stuck in the hypersensitive stage. The immune system continues sending cells to the nerves and triggering the pain response.

Some of these immune cells are called microglia, and other researchers have suggested that the microglia might actually be the key to understanding fibromyalgia. Basically, they are immune cells that cross the barrier between the blood and the brain. As they move through the body, microglia trigger the body to release chemicals that cause inflammation, which may create a cycle where the nerves are constantly inflamed.

It’s possible that both CRPS and fibromyalgia are caused by this interaction between the immune system and the nerves. By studying CRPS and other nervous system conditions, we may be able to learn more about fibromyalgia. And eventually, that may lead to a cure.