Structure and Function of the Lymphatic System
The primary function of the lymphatic system is to collect and transport fluid from the interstitial spaces back to the venous circulation (Fig. 25.1).30,35,47,52,105,107 This is accomplished with a series of lymph vessels and lymph nodes.30,35,107 The lymphatic system also has a role in the body's immune function.30,105,107 When the lymphatic system is compromised either by impairment of lymphatic structures or by an overload of lymphatic fluid, the result is swelling in the tissue spaces. Edema is a natural consequence of trauma to and subsequent healing of soft tissues. If the lymphatic system is compromised and does not function efficiently, lymphedema develops and impedes wound healing.
Major vessels of the lymphatic system.
Lymphedema is an excessive and persistent accumulation of extravascular and extracellular fluid and proteins in tissue spaces.11,18,26,47,61,107 It occurs when lymph volume exceeds the capacity of the lymph transport system, and it is associated with a disturbance of the water and protein balance across the capillary membrane. An increased concentration of proteins draws larger amounts of water into interstitial spaces, leading to lymphedema.26,41,107 Furthermore, many disorders of the cardiopulmonary system can cause the load on lymphatic vessels to exceed their transport capacity and subsequently cause lymphedema.41,61
Anatomy of the Lymphatic System
The lymphatic system is an open system.30,57,107 The lymphatic capillaries are situated close to the blood capillaries and are responsible for pulling the fluid into the lymphatic circulation (Fig. 25.2).30,47,57,105,107 Once inside the lymphatic vessels, the fluid is transported from lymph nodes to lymphatic trunks.30,57,105,107 The end result is the collection of the lymphatic fluid at the venous angles. In total, the body has 600 to 700 lymph nodes with the largest grouping found in the head and neck, around the intestines, and in the axilla and groin.30,107
Lymph capillary and larger lymph vessel.
Physiology of the Lymphatic System
The main components of lymphatic fluid are water and protein found in the extracellular spaces.26,30,41,57 In a normal state, the lymphatic system transports this fluid back to the venous circulation. The amount of fluid transported is the lymphatic load, and the amount of fluid the lymphatic system can transport is the transport capacity.30,107 When the balance in the interstitium is disrupted, whether by an increased lymphatic load or a decreased transport capacity, lymphedema can develop.26,30,41,107 Lymphatic load is increased when the venous system is unable to transport the required amount of fluid, which can occur in a patient with a venous insufficiency. Transport capacity is affected when the structures of the lymphatic system are impaired, for example, following surgery to remove lymph nodes in a patient with cancer.
Lymphedema can be classified as primary, meaning there is an inherent problem with the structures of the lymphatic system, or secondary, meaning there is an injury to lymphatic structures.30,41,107 This injury may be in the form of surgery, radiation, trauma, or infection. Lymphedema can also be caused by a combination of lymphatic-venous dysfunction commonly seen in patients with chronic venous insufficiency. Remember, lymphedema is not a disease but rather a symptom of a malfunctioning lymphatic system.
Primary lymphedema, although uncommon, is the result of insufficient development (dysplasia) and congenital malformation of the lymphatic system.35,40
Primary lymphedema can be divided into the age of presentation.30,41
Congenital: presents at birth and is sometimes known as Milroy's disease
Praecox (early): develops prior to 35 years of age
Tarda: develops after 35 years of age
Primary lymphedema typically affects more females than males and presents more often in the extremities, more so in the lower than upper extremities. However, it can be seen in other areas of the body as well.30,41,57,107 If not managed properly, this type of lymphedema can progress over time and present with skin changes (hyperkeratosis) and increased skin folds and skin creases.30,41,52,98,102
Most of the patients seen by healthcare practitioners for management of lymphedema have secondary lymphedema.83 By far, the most common causes of secondary lymphedema are related to the comprehensive management of cancers of the breast, pelvis, and abdomen.3,10,11,35,40,41,83,84 Secondary lymphedema is classified by the cause of the injury to the lymphatic structures including:
Surgical Dissection of Lymph Nodes
Lymph nodes and vessels often are surgically removed (lymphadenectomy) as an aspect of treatment of a primary malignancy or metastatic disease. For example, axillary lymph node dissection is performed in most types of breast cancer surgeries to determine the extent and progression of breast cancer.12,15,35,49 Likewise, pelvic or inguinal lymph node excision often is necessary for the treatment of pelvic or abdominal cancers.3,83,84
Infection and Inflammation
Inflammation of the lymph vessels (lymphangitis) or lymph nodes (lymphadenitis) and enlargement of lymph nodes (lymphadenopathy) can occur as the result of a systemic infection or local trauma. Any of these conditions can cause disruption of lymph circulation.35,40,41,107
Trauma, surgery, and neoplasms can block or impair the lymphatic circulation.35,41,97 Radiation therapy associated with treatment of malignant tumors also can cause fibrosis of vessels.3,12
Combined Venous-Lymphatic Dysfunction
Although not a primary disorder of the lymphatic system, chronic venous insufficiency and varicose veins are associated with venous stasis and accumulation of edema in the extremities.35,40,55,107 Dependent, peripheral edema occurring with long periods of standing or sitting is a common manifestation of chronic venous dysfunction. Edema decreases if the limb is elevated. Patients often report dull aching or tiredness in the affected extremity.27,35,40,55,79,107 If the insufficiency is associated with varicose veins, venous distention (bulging) also is notable. When edema persists, the skin becomes less supple over time and takes on a brownish pigmentation.
With time, a continued increase in the lymphatic work load imposed by the venous system causes a combined venous-lymphatic dysfunction. The lymphatic system begins to lose efficiency with the increased workload imposed over time, and a mixed edema results.107 A venous-lymphatic dysfunction has a mixture of low protein edema from the venous system and a high protein edema from the lymphatic system.
Clinical Manifestations of Lymphatic Disorders
Location. When lymphedema develops, it is most often apparent in the distal extremities, particularly over the dorsum of the foot or hand.26,41 The term dependent edema describes the accumulation of fluids in the peripheral aspects of the limbs, particularly when the distal segments are lower than the heart. In contrast, lymphedema can manifest more centrally, for example, in the axilla, groin, or even the trunk.26,35,40,107 Thorough assessment of the entire limb and regional area is important to define the extent of swelling.
Severity. The severity of lymphedema may be described quantitatively or qualitatively. Lymphedema is described by the severity of changes that occur in skin and subcutaneous tissues. The three categories—pitting, brawny, and weeping edema—are described in Box 25.1. Although all three types reflect a significant degree of lymphedema, they are listed in order of severity, from least severe to most severe.15,18,35,40,90
When skin is interrupted in a patient with lymphedema, it is common to note a seeping of clear, yellow-tinged fluid that is slightly thicker than vascular fluid in consistency. This increased viscosity comes from the high level of protein contained in the fluid transported by the lymphatic system. If the fluid is leaking out of the pores without interruption of the skin, this signals a severe nature to the condition.
BOX 25.1 Severity of Lymphedema
Pitting edema. Pressure on the edematous tissues with the fingertips causes an indentation of the skin that persists for several seconds after the pressure is removed. This reflects significant but short-duration edema with little or no fibrotic changes in skin or subcutaneous tissues.
Brawny edema. Pressure on the edematous areas feels hard with palpation. This reflects a more severe form of interstitial swelling with progressive, fibrotic changes in subcutaneous tissues.
Weeping edema. This represents the most severe and long-duration form of lymphedema. Fluids leak from cuts or sores; wound healing is significantly impaired. Lymphedema of this severity occurs almost exclusively in the lower extremities.
Another common way to define the severity of lymphedema is through staging. Staging refers to the physical condition of the limb only.52 The stages are described in Box 25.2.30,52,57,107 Stage 0 or the latency stage might present with the greatest possibility for reducing the onset of worsening lymphedema. This is especially true in the patient with secondary lymphedema from cancer surgery.
BOX 25.2 Stages of Lymphedema Stage 0—Latency Stage
Stage I—Reversible Stage Stage II—Spontaneously Irreversible
No outward swelling noted
Essentially asymptomatic with occasional reports of heaviness in the extremity
Despite reduced transport capacity, the body is still able to accommodate the lymphatic load
Stage III—Lymphostatic Elephantiasis
Fibrosis of tissue; brawny, hard swelling
Swelling is no longer pitting
Positive Stemmer sign
Frequent infections may occur
Positive Stemmer sign
Significant increase in limb volume
Typical skin changes noted (hyperkeratosis, papillomas, deep skin folds)
Bacterial and fungal infections of the skin and nails more common
Increased Size of the Limb
As the volume of interstitial fluid in the limb increases, so does the size of the limb (weight and girth).14,41,55,107 Increased volume, in turn, causes tautness of the skin and susceptibility to skin breakdown.15,35
Descriptors, such as mild, moderate, and severe, sometimes are based on how much larger the size of the edematous limb is compared to the noninvolved limb.61 However, there are no standard definitions associated with size and severity.
Paresthesia (tingling, itching, or numbness) or occasionally a mild, aching pain may be felt, particularly in the fingers or toes. In many instances the condition is painless, and the patient perceives only a sense of heaviness of the limb. Fine finger coordination also may be impaired as the result of the sensory disturbances.15,41,77,90
Stiffness and Limited Range of Motion
Range of motion (ROM) decreases in the fingers and wrist or toes and ankle or even in the more proximal joints, leading to decreased functional mobility of the involved segments.15,69
Decreased Resistance to Infection
Wound healing is delayed; and frequent infections (e.g., cellulitis) may occur.41,53,55,107 Early recognition and treatment of cellulitis has shown to be important in reducing further tissue damage.24,103
Examination and Evaluation of Lymphatic Function
A patient's history, a systems review, and specific tests and measures provide information to determine impairments and functional limitations that can arise from lymphatic disorders and the presence of lymphedema. Key components in the examination process that are particularly relevant when lymphatic dysfunction is suspected or lymphedema is present are summarized in this section.16,27,55,69,93,107 Other tests and measurements, such as vital signs, ROM, strength, posture, and sensory, functional, and cardiopulmonary testing, are also appropriate.
History and Systems Review
Note any history of infection, trauma, surgery, or radiation therapy. If a patient has a history of cancer and received chemotherapy, a review of the treatment and duration of the chemotherapy treatment is also important. The onset and duration of lymphedema, delayed wound healing, or previous treatment of lymphedema are pertinent pieces of information. Identify the occupation or daily activities of the patient, and determine if long periods of standing or sitting are required. Specific questioning to determine a pattern to the swelling can also aid in treatment planning.
Examination of Skin Integrity
Visual inspection and palpation of the skin provide information about the integrity of the skin. The location of the edema should be noted. When the limb is in a dependent position, palpate the skin to determine the type and severity of lymphedema and changes in skin and subcutaneous tissues. Describe the thickness and density of the tissue in each area of the limb. Areas of pitting, brawny, or weeping edema should be noted.
When palpating the skin over lymph nodes, note any tenderness of the nodes (cervical, supraclavicular, inguinal). Tenderness may or may not indicate ongoing infection or serious disease.36 Evidence of warm, enlarged, tender, painless, or adherent nodes should be reported to the physician.
The presence of wounds or scars and the color and appearance of the skin, which is often shiny and red in the edematous limb, should be noted. Document any papillomas, hyperkeratosis, or darkening of the skin, especially in the lower extremities. Photographic documentation is convenient in the clinical or home setting and provides visual evidence of changes in skin integrity. If a wound or scar is identified, its size should be noted, as should scar mobility or the presence of inflammation or infection in a wound.
A positive Stemmer sign, an indication of Stage II or III lymphedema, may be identified during palpation (Fig. 25.3). It is considered positive if the skin on the dorsal surface of the fingers or toes cannot be pinched or is difficult to pinch compared with the uninvolved limb.30,57,82,99,107 A positive Stemmer sign can be indicative of a worsening condition.
Stemmer sign: Objective test for lymphedema in the extremities. (From Hetrick47 p. 283 with permission.)
Circumferential measurements of the involved limb should be taken and compared with the noninvolved limb if the problem is unilateral.14,77 Identify specific intervals or landmarks at which measurements are taken so measurements during subsequent examinations are reliable. Use of circumferential measurements at anatomical landmarks has been shown to be a valid and reliable method of calculating limb volume.2,93
An alternative method of measuring limb size is to immerse the limb in a tank of water to a predetermined anatomical landmark and measure the volume of water displaced.14,93 Although this method also has been shown to be valid and reliable, for routine clinical use, it is more cumbersome and less practical than girth measurements.2,93
Bioimpedance measurements involve the use of a low-level, alternating electrical current to measure the resistance to the flow through the extracellular fluid in the upper extremities.25,81,96 The higher the resistance to flow, the more extracellular fluid present. Testing is fairly easy to perform, requiring only placement of skin electrodes.
For any bioimpedance value to be meaningful, initial testing must take place prior to surgery.65 Testing can then be performed at set intervals throughout the treatment continuum. This affords the opportunity for intervention at an earlier stage in the development of lymphedema. Other factors that affect volume in the body can theoretically affect the bioimpedance reading; therefore, this must be considered.25,65,81,82,96 There is still much to be learned about bioimpedance testing and how this correlates to lymphedema.
Lymphedema Risk Reduction
If a patient is at risk of developing lymphedema secondary to infection, inflammation, obstruction, surgical removal of lymphatic structures, or chronic venous insufficiency, reducing the risk of lymphedema should be the priority of patient management. In some situations, such as after removal of lymph nodes or vessels, risk-reducing measures may be needed for a lifetime. Even when a patient takes every measure to reduce the risk of edema, it still may develop at some time, particularly after trauma to or surgical removal of lymph vessels. Box 25.3 summarizes precautions and measures to reduce the risk of lymphedema.* The education of patients in the importance of risk eduction has been shown to be effective in lowering lymphedema symptoms.32,39,65 The effect of an increased body mass index (BMI) has shown mixed effect on the risk of developing lymphedema.43,45,65,68
BOX 25.3 Precautions, Risk Reduction, and Self-Management of Lymphedema Reducing the Risk of Lymphedema
Keep moving. Standing or sitting for long periods of time can cause pooling of fluid in the legs. Sit with both feet on the floor instead of legs crossed.
When traveling long distances by car, stop periodically, and walk around or support an involved upper extremity on the car's window ledge or seat back.
Elevate involved limb(s), and perform repetitive pumping exercises frequently during the day.
Be cautious about performing vigorous, repetitive activities with the involved limb.
Monitor the weight used with exercise. Increase weight slowly, and assess for feelings of heaviness, throbbing or aching in the limb.
Carry heavy loads, such as a heavy backpack or shoulder bag, over your uninvolved shoulder.
If you have lymphedema, wear compressive garments while exercising.
Wear clothing and jewelry that does not leave a mark or imprint on your skin when removed.
Monitor diet to maintain an ideal weight, and minimize sodium intake.
If possible, have blood pressures, needle sticks and blood draws performed in the uninvolved upper extremity or lower extremity.
Keep the skin clean and supple; use moisturizers, but avoid perfumed lotions.
Immediately attend to a skin abrasion or cut, an insect bite, a blister, or a burn.
Protect hands and feet; wear socks or hose, properly fitting shoes, rubber gloves, oven mitts, etc.
Use protective gloves when in contact with harsh detergents and chemicals.
Use caution when cutting nails. Push back cuticles instead of trimming.
Use an electric razor when shaving legs or underarms. If the underarm area is numb, use your eyes to ensure that good skin integrity was maintained.
Avoid hot baths, whirlpools, and saunas that elevate the body's core temperature.
Seek immediate medical care if infection is suspected. An infection may present with warmth, redness, tenderness, or rash on the skin. A fever may or may not be present.
Consult your physician immediately if a new onset of swelling is noted that does not resolve in 1–2 days.
Comprehensive management of lymphedema involves a combination of appropriate medical management and direct therapeutic intervention by a therapist combined with self-management by the patient. Treatment also includes appropriate pharmacological management for infection control and prevention or removal of excessive fluid and proteins.11,35,40
Because there is no cure for lymphedema, the main goal of treatment is to minimize the lymphedema as much as possible or return the lymphedema to a latency stage. In addition, the health of the tissue is important. Other goals include reducing risk of infection and softening of fibrotic tissue.30,107
The overall objective of management when lymphedema has developed is to improve drainage of obstructed areas and, theoretically, to channel fluids into more centrally located lymph structures that carry the fluid to the venous system. In order to affect the reduction of lymphatic and/or venous edema, the following should be considered.
Interstitial pressure is increased by external forces. These external forces can be from manual lymphatic drainage or compression therapy. An increased interstitial pressure causes an increased uptake of fluid. There is an increase of lymph production as more fluid enters the lymphatic system as well as an increase resorption of fluid by the venous system.30,65,107
Elevation can assist fluid return in stage I lymphedema or in venous edema. If elevation produces reduction, then a mild compression therapy (i.e., compression garment) may be indicated.26,35,52,57,97
Dynamic pressure changes within the body can assist lymphatic flow. Pressure changes can be in the form of diaphragmatic breathing or with muscle contractions. Breathing changes intrathoracic pressure and causes an increased uptake of lymph fluid in lymphatic trunks and ducts. Active muscle contractions change pressure in a localized area, enhancing the movement of lymph within lymph vessels. A muscle contraction combined with external forces from a bandage or compression garment can be even more effective in the movement of fluid.30,57,86,107
Comprehensive Regimens and Components
A comprehensive approach to the management of lymphedema is referred to in the literature by a variety of terms, including complex lymphedema therapy, complete or complex decongestive therapy (CDT), or decongestive lymphatic therapy.* Treatment typically is divided into two phases. Phase I is the intensive treatment phase; Phase II is the maintenance phase. The goal of Phase I treatment is reduction, whereas the goal of Phase II treatment is long-term management.15,52,57,107 Therapist-directed care is replaced by patient-directed care as treatment moves from Phase I to Phase II. Box 25.4 summarizes the components of these programs.
BOX 25.4 Components of a Decongestive Lymphatic Therapy Program Phase I Phase II
Self-MLD by the patient
Skin and nail care
Manual lymphatic drainage. Manual lymphatic drainage (MLD) involves slow, very light repetitive stroking and circular massage movements done in a specific sequence with the involved extremity elevated whenever possible.7,8,19,20,23,56,92,106,107 Proximal congestion in the trunk, groin, buttock, or axilla is cleared first to make room for fluid from the more distal areas. The direction of the massage is toward specific lymph nodes and usually involves distal-to-proximal stroking. Fluid in the involved extremity is then cleared, first in the proximal portion and then in the distal portion of the limb. Because manual lymphatic drainage is extremely labor- and time-intensive, methods of self-massage are taught to the patient as soon as possible in a treatment program.
Exercise. Active ROM, stretching, and low-intensity resistance exercises are integrated with manual drainage techniques.5,11,15,19,21,22,67,70,71,107 Exercises are performed while wearing a compressive garment or bandages and in a specific sequence. A low-intensity cardiovascular/pulmonary endurance activity, such as bicycling, often follows ROM and strengthening exercises. Specific exercises and a suggested sequence for the upper and lower extremities, compiled from several sources, are described and illustrated in the last section of this chapter.
Compression therapy. The type of compression used depends on the phase of treatment. During Phase I of treatment, only low-stretch bandages are used, which provide a low resting pressure on a limb but a high working pressure.30,107 High-stretch sports bandages, such as AceTM wraps, are not recommended for treating lymphedema.8,11,15,97 Given that a low-stretch bandage has a low resting pressure, the bandage can be worn during the day and at night. During the active reduction phase of treatment, it is recommended that compression be applied in the form of low-stretch bandaging at all times except for bathing.30,87,107 Under the low-stretch bandage, nonwoven padding is used and can be combined with foam pads to aid in the softening and reduction of fibrotic tissue (Fig. 25.4).
Upper extremity multilayer bandaging with padding from the upper arm to the hand.
As a patient moves from Phase I to a maintenance phase of treatment, compression is transitioned from low-stretch bandaging at all times to a compression garment during the day. A compression garment has a high resting pressure and low working pressure.30,107 Therefore, the use of a garment is not recommended during long periods of inactivity (night rest). The garment should be viewed as a method to maintain limb size during the day, giving a patient a more cosmetic appearance and ease of wearing clothing. During Phase II, it is still recommended that a patient wear the low-stretch bandages at night.15,87 In summary, the bandages are used for continued limb reduction, and a garment keeps the size of the extremity stable.
Compression garments are made in specific compression categories or classes (Table 25.1).15,87,107 Patients can most often be fit with a premade garment, but custom garments are available. For patients with lymphedema of the trunk, genital area, or face, custom garments can be fabricated.
TABLE 25.1Garment Compression Classification ||Download (.pdf) TABLE 25.1 Garment Compression Classification
|Class of Compression ||mm Hg ||Indications |
|Class 1 |
| ||20–30 mm Hg || |
|Class 2 |
| ||30–40 mm Hg || |
|Class 3 |
| ||40–50 mm Hg || |
Rarely used for UE lymphedema
Typically for stage II LE lymphedema
For patients with LE lymphedema involved in high-intensity, repetitive activities
|Class 4 |
| ||50–60 mm Hg || |
FOCUS ON EVIDENCE
Forner-Cordero and co-investigators31 conducted a study to identify the factors that best predicted response to CDT. A prospective multicenter, controlled cohort study was undertaken with 171 patients with breast cancer-related lymphedema. Following statistical analysis, compliance with bandaging was one of the most predictive indicators of response to CDT. The length of time from the development of the lymphedema to treatment did not predict response to treatment in this study. However, there was an inverse correlation between severity of lymphedema and response to CDT.
Another form of compression therapy is a pneumatic compression pump.66 The use of compression pumps, however, has been controversial over the years. Studies have shown that a compression pump can be a positive adjuvant therapy to CDT but should not be the sole therapeutic modality in the treatment of lymphedema.64,69,91 The main criticism of pump compression is the pumping of fluid in a distal to proximal sequence, which is opposite of the principles of MLD. There is also the potential to cause swelling in adjoining areas of the body, mainly the genital area, for a patient with lower extremity edema.9 When used correctly, a pneumatic compression pump can be a positive therapeutic intervention, especially in severe or refractory cases. More advanced pumps are now available that follow the sequence of MLD more closely, treating the trunk first and then the extremity in a proximal-to-distal sequence.
Skin care and hygiene. Lymphedema predisposes the patient to skin breakdown, infection, and delayed wound healing. Meticulous attention to skin care and protection of the edematous limb are essential elements of self-management of lymphedema.11,20,69,97
Use of Community Resources
A valuable resource for patients and healthcare professionals is the National Lymphedema Network (www.lymphnet.org). This nonprofit organization provides education and guidance about lymphedema. Other resources include the Peninsula Medical, Inc. website (www.lymphedema.org) and Lymph Notes (www.lymphnotes.com).