Lymphedema no longer rare, still underdiagnosed
■ Climbing rates of obesity may be adding to the burdens of the lymphatic system and boosting the number of cases of lymphedema.
By Susan J. Landers — Posted Dec. 3, 2007
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Washington -- Trained in family practice medicine, Caroline Fife, MD, didn't know what she was getting into when she decided to begin treating people with lymphedema.
She was operating a wound clinic at Memorial Hermann-Texas Medical Center in Houston and was receiving calls from people seeking relief for their swollen limbs. They seemed to have nowhere else to go. So she thought, "How hard can it be? I know a lot about leg swelling."
"Never say that," she cautioned. About nine years ago, she hired a part-time therapist for the clinic. Within a year she had eight therapists. "Patients came out of the woodwork."
She's been treating patients with lymphedema ever since, and she's had to reach out to others to learn how best to do so. "I had one lecture on the lymphatic system in medical school. [Lymphedema] seemed so rare I thought I would never need to know about it."
"It's an ignored field of medicine," said Saskia Thiadens, RN, the executive director of the National Lymphedema Network, based in Oakland, Calif., which she founded 20 years ago. "I would say that of the majority of patients who go to see their primary care physicians, the chances that he or she will be diagnosed are pretty slim."
Many patients are misdiagnosed for years, said Andrea Cheville, MD, associate professor of physical medicine and rehabilitation at the Mayo Clinic in Rochester, Minn. When diagnosing a patient with a swollen leg, for example, physicians tend to think, "Is it the heart? Is there a blood clot? Is there a tumor in the abdomen? Often patients get an echocardiogram. They will get an ultrasound of their leg and a CT scan of the belly. If those are negative, many times they are told, 'Well, this is nothing that is going to kill you. Aren't you glad? Good-bye.' "
Yet it's not so unusual to see patients, both men and women, with swollen limbs caused by a slowdown in the lymphatic system, which serves as an extensive drainage network to maintain the proper body fluid levels and defend against infections.
The numbers of people affected by the condition are difficult to come by. Estimates range from 35% to 45% of women treated for breast cancer -- a large number in itself considering that about 2.4 million women alive today have had breast cancer, according to the Centers for Disease Control and Prevention. This population is more commonly affected, since lymph nodes may be removed during treatment, thus slowing the entire system.
The lymphedema network has had a patient questionnaire on its Web site since 2001. Respondents are about equally divided as to whether they have primary lymphedema, which is congenital; or secondary, which seems to be due to a trauma, such as surgery.
But even that distinction has blurred as researchers are beginning to understand that everyone's lymph system is not created equal, Dr. Fife said. One person may have a fantastic drainage system that can continue to function well despite a huge assault, such as a radical mastectomy. Another person's system may be less robust and be disrupted by a minor injury.
Regardless, any slowdown can lead to the pooling of lymph and its cargo of protein molecules, salts, glucose, urea and other substances. The system carries several liters of fluid a day. An obstruction could result in tremendous amounts of fluid building in the body.
Another consequence of obesity
The rise in obesity is also contributing to the numbers of lymphedema patients. Ten years ago Dr. Fife didn't have any patients who weighed 500 pounds. Now, 2% or more of her patients are at this weight or heavier.
Why morbid obesity leads to lymphedema is unknown, but one theory is that fat may block the system. "So as everyone gets fatter, we have more lymphedema," Dr. Fife said.
Once a swelling has occurred, avoiding any stress on that body part is essential for preventing recurrences. Patients who have had lymphedema should not have a blood pressure cuff wrapped around the affected limb, or have injections or blood draws, Thiadens said. Go to the opposite arm or the leg.
Although there is no cure, controlling the swelling is important. Swelling can become permanent and cause irreversible limb distortions. In addition, other skin conditions can develop, including cellulitis. Plus, the body's defenses are impaired. One of Dr. Fife's patients, for instance, reads meters for the gas company. While tramping through backyards all day, he is bitten by mosquitoes and fire ants, and those bites often lead to infections and hospitalizations.
Treatment for lymphedema is a gentle massaging technique, called manual lymphatic drainage, which encourages lymph flow. Once a limb is reduced to near-normal size, efforts switch to compression bandages and garments to keep the swelling down.
Although lymph flow maps, complete with roadblocks, have not been available for years -- an earlier mapping technique had been painful and dangerous and was abandoned -- promising research is under way at Baylor College of Medicine, Houston.
Fluorescent dye is injected just under the skin, picked up by the lymphatics and transported throughout the system, said Eva M. Sevick-Muraca, PhD, professor of radiology at Baylor and principal investigator for the study. Its path is illuminated by shining near-infrared light on the skin. The light can penetrate several centimeters of tissue.
The technique, developed with funds from the American Cancer Society and the National Institutes of Health, has been tested in a phase I trial with normal subjects because, "We don't even know what normal lymph flow looks like," Dr. Sevick-Muraca said.
Researchers are beginning to test the system on lymphedema patients, specifically attempting to determine if lymph flow is enhanced by massage. "We image before, during and after the massage and see if the lymph is being pushed into the correct nodal basin," she said.