Overview
Acute versus gradual-onset lymphedema
Temporary versus chronic lymphedema
Risk factors
Diagnosis
The lymphatic system consists of a network of specialized lymphatic vessels and
various tissues and organs throughout the body that contain lymphocytes (white
blood cells) and other cells that help the body fight infection and disease.
The lymphatic vessels are similar to veins but have thinner walls. Some of
these vessels are very close to the skin surface and can be found near veins;
others are just under the skin and in the deeper fatty tissues near the muscles
and can be found near arteries. Muscles and valves within the walls of the
lymphatic vessels near the skin surface help pick up fluid and proteins from
tissues throughout the body and move the lymph in one direction, toward the
heart. Lymph is slowly moved through larger and larger lymphatic vessels and
passes through small bean-shaped structures called lymph nodes. Lymph nodes
filter substances that can be harmful to the body and contain lymphocytes and
other cells that activate the immune system to fight disease. Eventually,
lymph flows into one of two large ducts in the neck region. The right
lymphatic duct collects lymph from the right arm and the right side of the head
and chest, emptying it into the large vein under the right collarbone. The
left lymphatic duct or thoracic duct collects lymph from both legs, the left
arm, and the left side of the head and chest, emptying it into the large vein
under the left collarbone.
The lymphatic system collects excess fluid and proteins from the body tissues
and carries them back to the bloodstream. Proteins and substances too big to
move through the walls of veins can be picked up by the lymphatic vessels
because they have thinner walls. Edema may occur when there is an increase in
the amount of fluid, proteins, and other substances in the body tissues because
of problems in the blood capillaries and veins or a blockage in the lymphatic
system.
Lymphedema may be either primary or secondary. Primary lymphedema is a rare inherited condition in which lymph nodes and lymph vessels are absent or abnormal. Secondary lymphedema can be caused by a blockage or cut in the
lymphatic system, usually the lymph nodes in the groin area and the armpit.
Blockages may be caused by infection, cancer, or scar tissue from radiation
therapy or surgical removal of lymph nodes. Lymphedema that is secondary to cancer is not usually life-threatening. This summary discusses secondary
lymphedema.
Acute versus gradual-onset lymphedema
There are four types of acute lymphedema. The first type of acute lymphedema
is mild and lasts only a short time, occurring a few days after surgery
to remove the lymph nodes or after injury to the lymphatic vessels or veins just
under the collarbone. The affected limb may be warm and slightly red, but is
usually not painful and gets better within a week by keeping the affected
arm or leg supported in a raised position and by contracting the muscles in the
affected limb (for example, making a fist and releasing it). The second type
of acute lymphedema occurs 6 to 8 weeks after surgery or during a course of radiation therapy. This type may be caused by inflammation of either lymphatic
vessels or veins. The affected limb is tender, warm or hot, and red and is
treated by keeping the limb supported in a raised position and taking anti-inflammatory drugs. The third type of acute lymphedema occurs after an
insect bite, minor injury, or burn that causes an infection of the skin and the
lymphatic vessels near the skin surface. It may occur on an arm or leg that is chronically swollen. The affected area is red, very tender, and hot and is
treated by supporting the affected arm or leg in a raised position and taking antibiotics. A compression pump should not be used and the affected area should not be wrapped with
elastic bandages during the early stages of infection. Mild
redness may continue after the infection. The fourth and most common type of
acute lymphedema develops very slowly and may become noticeable 18 to 24 months
after surgery or not until many years after cancer treatment. The patient may
experience discomfort of the skin; aching in the neck, shoulders, spine,
or hips caused by stretching of the soft tissues or overuse of muscles; or
posture changes caused by increased weight of the arm or leg.
Temporary versus chronic lymphedema
Temporary lymphedema is a condition that lasts less than 6 months. The skin
indents when pressed and stays indented, but there is no hardening of the skin.
A patient may be more likely to develop lymphedema if he or she has one of the following:
- Surgical drains that leak protein into the surgical site.
- Inflammation.
- Inability to move the limb(s).
- Temporary loss of lymphatic function.
- Blockage of a vein by a blood clot or inflammation.
Chronic (long-term) lymphedema is the most difficult of all types of edema to
treat. The damaged lymphatic system of the affected area is not able to keep
up with the increased need for fluid drainage from the body tissues. This may
be caused by one of the following:
- Recurrence or spread of a tumor to the lymph nodes.
- Infection of and/or injury to the lymphatic vessels.
- Periods of not being able to move the limbs.
- Radiation therapy or surgery.
- Inability to control early signs of lymphedema.
- Blockage of a vein by a blood clot.
A patient who is in the early stages of developing lymphedema will have
swelling that indents with pressure and stays indented but remains soft. The
swelling may easily improve by supporting the arm or leg in a raised position,
gently exercising, and wearing elastic support garments. Continued problems
with the lymphatic system cause the lymphatic vessels to expand, allowing lymph to flow
back into the body tissues and make the condition worse. Pain,
heat, redness, and swelling result as the body tries to get rid of the extra fluid.
The skin becomes hard and stiff and no longer improves with raised support of
the arm or leg, gentle exercise, or elastic support garments.
Patients with chronic lymphedema are at increased risk of infection. No
effective treatment is yet available for patients who have advanced chronic
lymphedema. Once the body tissues have been repeatedly stretched, lymphedema
may recur more easily.
Risk factors
Factors that can lead to the development of lymphedema include radiation
therapy to an area where the lymph nodes were surgically removed, problems
after surgery that cause inflammation of the arm or leg, a larger number of lymph
nodes removed in surgery, and being older. The part of the body treated may affect where lymphedema occurs. For example, lymphedema in the arms may occur after treatment for breast cancer and lymphedema in the legs may occur after treatment for vulvar cancer.
Risk factors for lymphedema include the following:
- Breast cancer, if the patient received radiation therapy or had lymph nodes
removed. Radiation therapy to the underarm area after surgical removal
of the lymph nodes and having a larger number of lymph nodes removed increases the
risk of lymphedema.
- Surgical removal of lymph nodes in the underarm, groin, or pelvic regions.
- Radiation therapy to the underarm, groin, pelvic, or neck regions.
- Scar tissue in the lymphatic ducts or veins and under the collarbones,
caused by surgery or radiation therapy.
- Cancer that has spread to the lymph nodes in the neck, chest, underarm, pelvis, or abdomen.
- Tumors growing in the pelvis or abdomen that involve or put pressure on
the lymphatic vessels and/or the large lymphatic duct in the chest and
block lymph drainage.
- Having an inadequate diet or being overweight. These conditions may delay
recovery and increase the risk for lymphedema.
Diagnosis
Specific criteria for diagnosing lymphedema do not yet exist. About half of
patients with mild edema describe their affected arm or leg as feeling heavier
or fuller than usual. To evaluate a patient for lymphedema, a medical history
and physical examination of the patient should be completed. The medical
history should include any past surgeries, problems after surgery, and the time
between surgery and the onset of symptoms of edema. Any changes in the edema
should be determined, as should any history of injury or infection. Knowing
which medications a patient is taking is also important for diagnosis.
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