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A healthy lymphatic system is generally able to prevent or decrease the amount of acute edema. Under normal conditions, the transport capacity of the lymphatic system is approximately 10 times greater than the physiologic amount of the lymphatic loads.
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The decisive difference between lymphedema and virtually all other types of edema is the high content of plasma proteins in the interstitial fluid.
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The diagnosis of lymphedema is made in most cases by patient history, systems review, inspection, palpation, and a few select noninvasive tests such as volume or girth measurement.
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Tissue lesions common in lymphedema, caused by the impaired lymph vascular system and/or other co-morbid conditions, may present as simple superficial excoriations to multifarious ulcers with complex etiologies.
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Compression is the cornerstone of lymphedema therapy.
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Complete decongestive therapy is a two-phase intervention for lymphedema that is noninvasive, highly effective, and cost-effective that can reduce and maintain limb size.
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The goal of exercise is to improve lymphatic flow without adding undue stress to the impaired lymphatic system.
Lymphedema is a chronic, incurable condition that is characterized by an abnormal collection of fluid owing to an anatomic alteration of the lymphatic system. Throughout the world, it is estimated that one person in 30 is afflicted with lymphedema. Lymphedema can lead to significant impairments in function, integumentary disorders, pain, and psychological issues. Appropriate identification and intervention of this disease can improve functional and aesthetic outcomes and patient quality of life. This chapter describes the function of the lymphatic system and the etiologies of lymphedema. Examination, intervention, and preventive measures are discussed, as well as impairments associated with lymphedema and other complications involving the upper extremity.
Etiology of Lymphedema
The lymphatic system has two main functions. First, it provides significant immune function by protecting the body from disease and infection via production, maintenance, and distribution of lymphocytes. The second function is the facilitation of fluid transport from the interstitial tissues back into the bloodstream. This fluid transport maintains normal blood volume and eliminates chemical imbalances in the interstitial fluid. The substances transported by the lymphatic system are called lymphatic loads (LL) and consist of protein, water, cellular debris, and fat (from the digestive system). These lymphatic loads are filtered by regional and central lymph nodes before reentry into the venous blood system.
The lymphatic capillaries, the beginning of the lymphatic system, abound in the dermis at the dermal-epidermal junction, forming a flat, two-dimensional continuous network over the entire body with the exception of the central nervous system and cornea. Unlike blood capillaries that consist of continuous tubules of endothelial cells, lymphatic capillaries consist of overlapping endothelial cells ( Fig. 64-1 ). A surrounding fiber net of anchoring filaments, arranged around the lymph capillaries, enables these vessels to stay open at the junction between the overlapping cells even under high tissue pressure ( Fig. 64-2 ). The lymphatic loads are resorbed by the lymph capillaries and flow into larger lymph vessels called precollectors, which then drain into collectors. Lymph collectors have valves, spaced every 6 to 20 mm. Segments between two valves in a lymph collector are called lymph angions. The contraction of smooth muscle in each angion (called lymphangiomotoricity) generates the propulsive force of lymph flow along the lymph vessel. The frequency of contraction of lymph angions at rest is 6 to 10 contractions per minute. The propulsion directs the lymph fluid into regional and central lymph nodes to be filtered ( Fig. 64-3 ). Ultimately, the lymph fluid empties into the venous system through the left and right venous angles, i.e., at the junctions between the subclavian and jugular veins at the level of the clavicles.
The amount of lymphatic load transported by the lymphatic system is dependent on the same forces that propel blood in the blood capillaries. Starling’s equation ( Table 64-1 ) describes the balance or equilibrium of capillary filtration and reabsorption. , The transport of fluid through the membrane of blood capillaries depends on four variables: blood capillary pressure, colloid osmotic pressure of the plasma proteins, colloid osmotic pressure of the proteins located in the interstitial tissue, and tissue pressure.
| Legend | Definition |
|---|---|
| P c − Pif | Hydrostatic pressure gradient |
| π p − π if | Colloid osmotic pressure gradient |
| K f | Permeability of water and small solutes |
| σ | Permeability of plasma proteins |
| J v | Capillary filtrate |
| J L | Lymphatic return |
| J v > J L | Edema |
Ultrafiltration is defined as blood capillary pressure greater than the colloid osmotic pressure of plasma proteins. Reabsorption is defined by blood capillary pressure less than the colloid osmotic pressure of plasma proteins.
A shift in Starling’s equilibrium toward an increase in ultrafiltration (such as occurs in cases of inflammation or venous hypertension) or decreased colloid osmotic pressure (associated with hypoproteinemia) can cause an increased amount of lymphatic load, placing a higher burden on the lymphatic system. A healthy lymphatic system is generally able to prevent or decrease the amount of acute edema. Under normal conditions, the transport capacity (TC) of the lymphatic system is approximately 10 times greater than the physiologic amount of the lymphatic loads. This is known as the functional reserve (FR) of the lymphatic system ( Fig. 64-4 ). As long as the lymphatic load remains lower than the transport capacity of the lymphatic system, the lymphatic compensation is successful. If the lymphatic load exceeds the transport capacity, edema will occur. This is called dynamic insufficiency of the lymphatic system; the lymph vessels are intact but overwhelmed ( Fig. 64-5 ). The result is edema, which can usually be successfully treated with elevation, compression, and decongestive exercises (any basic exercise to facilitate the muscle pump).
Lymphedema is caused by mechanical insufficiency or low-volume insufficiency of the lymphatic system. The transport capacity drops below the physiologic level of the lymphatic loads ( Fig. 64-6 ). This means the lymphatic system is not able to clear the interstitial tissues, and an accumulation of high protein fluid is the result. This is recognized as lymphedema or lymphostatic edema. The decisive difference between lymphedema and virtually all other types of edema is the high content of plasma proteins in the interstitial fluid. Over time (several months to years), this can lead to fibrosis of all affected tissue structures and is readily evident in the texture and consistency of the involved integument ( Fig. 64-7 ).
Sometimes the etiology of edema is uncertain, and there is no clear clinical distinction between lymphedema and other types of edema. Some swelling may be a mixture of both edema and lymphedema, as occurs when the functional reserve of the lymphatic system is exceeded and the lymph transport capacity is compromised. The progression of lymphedema from the first perception of “heaviness” by the patient and nonresolving edema to irreversible fibrotic changes takes time. In an effort to standardize the associated integumentary changes, staging and classification systems have been developed. The staging system is used clinically to describe the subjective and objective integument changes. The classification system is used for unilateral limb involvement and is based on circumferential limb measurements. Tables 64-2 and 64-3 show the stages and severity classification systems for lymphedema. Early accurate diagnosis, patient education, and appropriate treatment will decrease the amount of time needed to achieve limb reduction, skin changes, and overall improvement or restoration of function.
| Stage | Description |
|---|---|
| 0 | Latent or subclinical condition: swelling is not evident despite impaired lymph transport. |
| I | Reversible lymphedema: early accumulation of protein-rich fluid, elevation reduces swelling; tissue pits on pressure. |
| II | Spontaneously irreversible lymphedema: proteins stimulate fibroblast formation; connective and scar tissue proliferate; minimal pitting even with moderate swelling. |
| III | Lymphostatic elephantiasis: hardening of dermal tissues, papillomas of the skin, tissue appearance elephant-like. (Not everyone progresses to this stage.) |
| Classification | Description |
|---|---|
| Minimal | <20% increase in limb volume |
| Moderate | 20%–40% increase in limb volume |
| Severe | >40% increase in limb volume |
The etiology of lymphedema is currently classified into two major categories: primary and secondary lymphedema. Primary lymphedema is caused by a condition that is either hereditary or congenital. In the United States, it is estimated that approximately 2 million people have primary lymphedema. Eighty-three percent of primary lymphedema cases manifest before the age of 35 (lymphedema praecox) and 17% manifest after the age of 35 (lymphedema tardum). The onset of primary lymphedema can occur at birth (Milroy’s disease or Meige’s syndrome), but most often the onset is during puberty or around the age of 17 years. Eighty-seven percent of all cases of primary lymphedema occur in females, and the lower extremities are more often involved than other body parts.
Secondary lymphedema is caused by some identifiable insult to the lymphatic system. Secondary lymphedema etiologies include inflammation, infection, radiation therapy, surgery, filariasis (parasitic infection), trauma, iatrogenic alterations, artificial self-induced lymphedema, benign or malignant tumor growth, and chronic venous insufficiency. Approximately 2.5 to 3 million people in the United States have been diagnosed with secondary lymphedema. One third of patients who undergo mastectomy (with lymph node resection) secondary to breast cancer develop secondary lymphedema of the upper extremity (the reported incidence varies depending on study parameters). Radical lymph node dissection with prostate cancer causes lymphedema of one or both legs and often the genitals in more than 70% of the cases. Secondary lymphedema is usually unilateral; however, it may present in both limbs. It is important to note, however, that involvement of the limbs and presentation of the edema is generally not symmetrical. One limb will appear larger, and it is this limb that should be addressed first with respect to intervention strategies.
Lymphedema can lead to numerous health-related and emotional problems. Of concern is the high risk of infection and skin changes associated with chronic lymphedema, particularly for patients who do not receive appropriate intervention. Fluid accumulation in the tissues is an ideal medium for pathogen growth, and cellulitis and venous-type ulceration (particularly of the lower extremities) can be a common occurrence for patients with lymphedema. Patients also experience embarrassment and social barriers because of the increased limb size, discomfort, diminished movement and function of the affected limb or limbs, and difficulty donning and doffing clothing, each of which may compromise a person’s quality of life.
Differential Diagnosis of Breast Cancer–Related Edemas
(Adapted from Linda T. Miller, Management of Breast Cancer Related Edemas, 5th Edition).
Postoperative Edema
Although lymphedema can occur at any time after treatment for breast cancer, postoperative edema, often called acute lymphedema, occurs within the first 6 weeks after breast cancer surgery. Mild postoperative edema and subtle changes in tissue are expected and often transient, resolving with the healing of the surgical site and lymphatic regeneration. Often, therapeutic interventions such as simple active range of motion (ROM) exercises and appropriate positioning may be all that is necessary to assist in resolving the edema. Any individual who undergoes axillary, breast, or chest surgery is considered to be at risk for the development of lymphedema in the trunk quadrant and upper extremity of the affected side. Patient education about the signs and symptoms of lymphedema as well as proper management and protection of the limb at risk should be implemented.
Cording-Related Edema
At approximately 2 to 3 weeks after the axillary dissection, many patients will experience pain along the anteromedial aspect of the involved upper extremity, which appears to follow a neurovascular pattern. Cordlike, superficial, fibrous bands usually develop, which are often visible and palpable, especially through the anterior elbow and ventral forearm. Pain associated with cording, also known as sclerosing lymphangitis, , is often described as a “drawing” or “pulling” feeling, which extends from the axilla to the fingers. Shoulder flexion with the elbow extended becomes increasingly difficult because of tightness of the cords.
These cordlike bands usually soften and often disappear at approximately 8 to 12 weeks. However, mild moist heat applied to the outstretched arm, followed by gentle, skillful stretching of the cords and soft tissue, can provide a dramatic decrease in pain and increase in ROM in only a few therapy sessions.
Often, cording-related edema is most noticed initially in the ventral forearm and radial hand and is commonly described as “painful,” fitting the pain pattern as described previously. This edema frequently presents during the first 3 months postoperatively but can appear with the same signs and symptoms years later and usually corresponds to some traumatic irritation of the sclerosed lymphatic vessels, such as a quick stretch of the arm or an attempt to lift something that is too heavy.
Edema that presents with cording as its underlying cause must be treated concurrently with the cording. Manual therapy, including gentle passive ROM of the shoulder with elbow and wrist extension and mild skin traction, can be followed by the appropriate edema techniques. When treated early and appropriately, cording-related edema usually resolves.
Chemotherapy-Induced Edema
Edema of the arm or adjacent trunk may develop in patients undergoing certain chemotherapy regimens. Corticosteroids such as dexamethasone and glucocorticoids may cause short-term fluid retention throughout the body. , Because of the axillary dissection, drainage from the ipsilateral lymph vessels may be impaired. Any increase in fluid in the compromised area can tip the balance in favor of an edematous condition.
At the first sign of edema, management techniques should be initiated. Treatment success may be hampered as long as the patient continues to receive chemotherapy. However, once chemotherapy is concluded, the edema can resolve with continued treatment.
Emphasis must be placed on early detection and treatment of these acute edemas. They often will resolve with skillful, early intervention. However, if allowed to progress, even these early edemas can go on to become chronic conditions.
Chronic Lymphedema
Lymphedema occurs between the deep fascia and the skin. In addition to a decrease in lymphatic transport capacity, there is also a decrease in macrophage activity and an increase in the action of fibroblasts. , The accumulating protein creates an environment for chronic inflammation and progressive fibrosis of the tissues. Fibrosis of the initial lymphatic vessels and collectors leads to a failure of the endothelial junctions to close and valvular dysfunction in the deeper collecting vessels. This results in the failure of the vessels to remove proteins from the interstitium. As the condition progresses, protein continues to accumulate, forming a network of fibrosclerotic tissue.
Other histologic changes, such as deep fascial thickening, occur as edema progresses. Changes such as circumference and tissue texture can easily be detected and documented. However, before the development of such obvious symptoms, an increase in the infection rate (recurrent cellulitis) may indicate an impending lymphedema. ,
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