Management of Lymphatic Disorders
The
lymphatic system consists of a set of vessels that spread throughout most of
the body. These vessels start as lymph capil-laries that drain unabsorbed
plasma from the interstitial spaces (spaces between the cells). The lymphatic capillaries
unite to form the lymph vessels, which pass through the lymph nodes and then
empty into the large thoracic duct that joins the jugular vein on the left side
of the neck.
The
fluid drained from the interstitial space by the lymphatic system is called
lymph. The flow of lymph depends on the in-trinsic contractions of the lymph
vessels, the contraction of mus-cles, respiratory movements, and gravity. The
lymphatic system of the abdominal cavity maintains a steady flow of digested
fatty food (chyle) from the intestinal mucosa to the thoracic duct. In other
parts of the body, the lymphatic system’s function is re-gional; the lymphatic
vessels of the head, for example, empty into clusters of lymph nodes located in
the neck, and those of the ex-tremities empty into nodes of the axillae and the
groin.
Lymphangitis
is an acute inflammation of the lymphatic channels. It arises most commonly
from a focus of infection in an extrem-ity. Usually, the infectious organism is
a hemolytic Streptococcus. The
characteristic red streaks that extend up the arm or the leg from an infected
wound outline the course of the lymphatic vessels as they drain.
The
lymph nodes located along the course of the lymphatic channels also become
enlarged, red, and tender (acute lym-phadenitis). They can also become necrotic
and form an abscess (suppurative lymphadenitis). The nodes involved most often
are those in the groin, axilla, or cervical region.
Because
these infections are nearly always caused by organisms that are sensitive to
antibiotics, it is unusual to see abscess forma-tion. Recurrent episodes of
lymphangitis are often associated with progressive lymphedema. After acute
attacks, an elastic compression stocking or sleeve should be worn on the
affected extremity for several months to prevent long-term edema.
Lymphedemas
are classified as primary (congenital malforma-tions) or secondary (acquired
obstructions). Tissue swelling oc-curs in the extremities because of an
increased quantity of lymph that results from obstruction of lymphatic vessels.
It is especially marked when the extremity is in a dependent position.
Initially, the edema is soft, pitting, and relieved by treatment. As the
con-dition progresses, the edema becomes firm, nonpitting, and un-responsive to
treatment. The most common type is congenital lymphedema (lymphedema praecox),
which is caused by hy-poplasia of the lymphatic system of the lower extremity.
This dis-order is usually seen in women and first appears between ages 15 and
25.
The
obstruction may be in the lymph nodes and the lymphatic vessels. Sometimes, it
is seen in the arm after an axillary node dis-section (eg, for breast cancer)
and in the leg in association with varicose veins or chronic thrombophlebitis.
In the latter case, the lymphatic obstruction usually is caused by chronic
lymphangitis. Lymphatic obstruction caused by a parasite (filaria) is seen
fre-quently in the tropics. When chronic swelling is present, there may be
frequent bouts of acute infection characterized by high fever and chills and
increased residual edema after the inflamma-tion has resolved. These lead to
chronic fibrosis, thickening of the subcutaneous tissues, and hypertrophy of
the skin. This condition, in which chronic swelling of the extremity recedes
only slightly with elevation, is referred to as elephantiasis.
The
goal of therapy is to reduce and control the edema and pre-vent infection.
Active and passive exercises assist in moving lym-phatic fluid into the
bloodstream. External compression devices milk the fluid proximally from the
foot to the hip or from the hand to the axilla. When the patient is ambulatory,
custom-fitted elastic compression stockings or sleeves are worn; those with the
highest compression strength (exceeding 40 mm Hg) are required. When the leg is
affected, strict bed rest with the leg elevated may aid in mobilizing the
fluids.
As
initial therapy, the diuretic furosemide (Lasix) is prescribed as needed to
prevent the fluid overload that can result from the mo-bilization of
extracellular fluid. Diuretics have also been used pal-liatively for lymphedema
in conjunction with elevating the leg and wearing elastic compression stockings
or sleeves. However, the use of diuretics alone has little benefit because
their main action is to limit capillary filtration by decreasing the
circulating blood volume. If lymphangitis or cellulitis is present, antibiotic
therapy is initiated. The patient is taught to inspect the skin for evidence of
infection.
Surgery
is performed if the edema is severe and uncontrolled by medical therapy, if
mobility is severely compromised, or if infec-tion persists. One surgical
approach involves the excision of the affected subcutaneous tissue and fascia,
with skin grafting to cover the defect. Another procedure involves the surgical
relocation of su-perficial lymphatic vessels into the deep lymphatic system by
means of a buried dermal flap to provide a conduit for lymphatic drainage.
After
surgery, the management of skin grafts and flaps is the same as when these
therapies are used for other conditions. Prophylactic antibiotics may be
prescribed for 5 to 7 days. Constant elevation of the affected extremity and
observations for complications are essential. Complications may include flap
necrosis, hematoma or abscess under the flap, and cellulitis. The nurse
instructs the patient or caregiver to inspect the dressing daily. Unusual
drainage or any inflammation around the wound margin may suggest infection and
should be reported to the physician. The patient is informed that there may be
a loss of sensation in the skin graft area. The patient is also instructed to
avoid the application of heating pads or exposure to sun to prevent burns or
trauma to the area.
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