Every illness, disease, or medical condition has what we call a natural history. The natural history describes what typically happens for that patient with a particular problem. Natural history may include how quickly the disease advances or progresses. It also includes what signs and symptoms develop at each stage. Prognosis and what to expect at different time points of disease are also part of the natural history.
In this study, the natural history of a condition called complex regional pain syndrome (CRPS) is reviewed and analyzed to help us better understand this condition. Complex regional pain syndrome or CRPS is a painful condition that affects the arm and hand or leg and foot. It usually occurs after trauma of some sort, including surgery.
Complex regional pain syndrome (CRPS) comes with a wide range of symptoms. Most people report a cutting, sharp, or stabbing pain. It’s intense and it’s constant. They may also notice increased or decreased sweating of the area. Hair patches or hair loss (or both) are common. Muscle spasm and weakness are part of the clinical picture early on for most patients.
Some patients’ have a change in temperature, too. The limb may become very hot and sweaty or cold and clammy. It’s not entirely clear what causes this condition or its symptoms. It looks like changes in both the central (brain and spinal cord) and peripheral nervous systems (spinal nerves) are part of the process. Interactions between the nervous system and the immune system may be equally important.
Some recent research has taken a look at the nerves, blood vessels, and hair follicles of patients with CRPS. It appears that tiny nerves to the blood vessels are missing in patients with CRPS. The walls of the arteries become hypertrophied (thicker) cutting down blood flow to the area. Even the layers of the blood vessels are disrupted.
Women are more likely to develop CRPS compared to men, so there may be a neurohormonal factor as well. The interaction between the nervous system and hormones is complex and not well understood. Any number of problems in communication between these two systems could set off a chain reaction that ends in developing CRPS.
All of these changes probably contribute to the symptoms described with CRPS. Most people think the syndrome occurs after healing is complete. But one theory is that there is ongoing inflammation. The inflammation causes nerve endings to become extra sensitive.
Until we have more information about what is actually causing CRPS, describing the natural history can be very helpful. Patients, physicians, physical therapists, and other health care professionals can use this information to plan treatment and help the patient manage their own symptoms.
In this study, over 650 patients with CRPS for at least one-year duration were analyzed. They each completed an in-depth interview by completing a survey answering questions about their experiences with CRPS. They reported on what triggered the development of CRPS, what makes their symptoms better or worse, and how the pattern of pain spread over time.
They also answered questions about work, quality of life, education level, general health, and family history. Each of these factors was examined on a continuum of time. In other words, as the disease changed and progressed (got worse), the researchers looked to see if there was some connection between those changes and any of these parameters.
Here’s what they found. The longer a person had CRPS, the more intense the pain became over time. Pain triggered by touch or made worse by touch got worse over time as the disease got worse. Time of day for the worst pain varied but everyone agreed that pain in the evening and at night was a definite problem. Patients described the effect of their symptoms as more likely to be tiring and exhausting than fearful.
It was very common for patients to report painful symptoms that spread down the arm or leg and from one area to another. For example, symptoms spread from one arm to the leg on the same side or even the opposite side. Sometimes the pain spread over the entire body. There were patterns to the way the pain seemed to spread. The most common pattern was contiguous (slow spread from one area to the next).
There were patterns as to how the painful symptoms responded. Medication, rest, hot weather, and hot or warm water were more likely to provide relief from symptoms. Massage, elevation of the limb, and physical therapy were also reported helpful to some patients. Although these kinds of treatment offered pain relief, there was no obvious time period linked with improvement. In other words, patients who were treated early on had the same relief as patients who were treated much later in the course of their disease. For a small number of people, nothing helped.
Aggravating factors (that is to say, things that could be counted on to make the symptoms worse) included cold, physical activity, and some specific motions. Standing still too long, holding the arms up overhead, being in a car (as driver or passenger) for a long time, and stress were listed as aggravating factors.
When looking at symptoms as they unfolded over time, the authors saw that skin color changes and skin temperature changes were common. Nearly three-fourths of the patients had skin color changes in the first five years of their disease. This percentage increased to 83 per cent after 15 years. Skin temperature changes increased over time. The longer the patient had CRPS, the more likely the patient would report skin temperature changes.
Most other symptoms (e.g., swelling, sweating, abnormal limb position) followed the same pattern of increasing over time with disease duration. The exception to this pattern was weakness and the initiation of movement. Both of those problems were present within the first five years and stayed about the same as time went by.
One important finding was that the number of patients reporting constant, intense pain (or other symptoms) did not increase over time. In other words, symptoms gradually got worse for those who had symptoms. Those who didn’t report specific problems early on did not usually develop them later.
The authors conclude that by looking back over time for many patients (rather than just following one person), they were able to see a pattern of disease progression for CRPS. Most of the bothersome symptoms were present early on. They get worse over time. No one ever had a spontaneous cure or recovery. CRPS can be a very disabling, life-altering illness that only responds moderately to most of today’s treatments.
Scientists are pinning their hopes on finding an effective drug therapy that will minimize the problems seen with CRPS. Right now, research efforts are focused on developing substances that will target the nervous system and/or the immune system.