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602.e2 Lymphedema

Lymphedema Client Education
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BASIC INFORMATION
depression or pitting may be observed after
digital compression of the area. In primary increased vascular permeability, or elevated
capillary hydrostatic pressure from venous
Definition lymphedema, pain typically indicates second- obstruction, arteriovenous (AV) fistula, or
Lymphedema is a swelling of protein-rich ary infection. severe right-sided congestive heart failure.
interstitial fluid caused by impaired lymphatic • Regional lymph nodes can be underde-
function. The condition can be localized, veloped/absent (primary) or enlarged DIAGNOSIS
regional, or widespread. Lymphedema is clas- (secondary).
sified as primary (developmental) or secondary • Isolated swellings with pain or inflamma- Diagnostic Overview
(due to neoplasia, trauma, surgery, infection, tion suggest associated cellulitis, trauma, or The diagnosis of lymphedema is suspected when
radiation therapy) in origin. neoplasia. other causes of (nonpainful) regional edema
• Intermandibular edema with normal jugular have been excluded.
Synonyms venous pressure suggests lymphatic obstruc-
Although not specific for lymphedema, other tion. When there is jugular venous distention, Differential Diagnosis
terms for edematous states include anasarca, cranial vena caval compression or thrombosis Lymphedema must be distinguished from other
pitting edema, subcutaneous edema (p. 284), or an obstruction within the tricuspid valve causes of tissue swelling:
and ventral edema. orifice is more likely. • Overinfusion of intravenous crystalloid fluids;
• Chronic lymphedema or that associated with migration of subcutaneous fluids
Epidemiology lymphangitis can produce firm, nonpitting • Arteriovenous fistula (congenital or acquired)
SPECIES, AGE, SEX swellings, skin ulceration, or oozing of serum • Venous obstruction or thrombophlebitis
• Dogs or cats across the skin. • Hypoproteinemia
• Primary lymphedema: puppies and young • Lymphedema related to lymphangiosar- • Vasculitis
dogs coma can be associated with ecchymotic • Insect bites or other forms of envenomation
• Secondary lymphedema: any age, although hemorrhages. • Localized or generalized allergic reactions
often older animals • Postinfarction edema (e.g., after aortic
Etiology and Pathophysiology thromboembolism in cats)
GENETICS, BREED PREDISPOSITION • Lymph is produced by ultrafiltration of • Right-sided congestive heart failure, including
• Primary lymphedema has been observed in capillary blood related to Starling forces cardiac tamponade (subcutaneous edema
English bulldogs, Labrador retrievers, whip- in the microcirculation. There is normally of heart failure typically occurs along with
pets, and other breeds a continuous resorption of lymph from ascites or pleural effusion)
• Idiopathic lymphedema may be more common the interstitium by lymphatic vessels and • Cellulitis, abscess, or localized tissue infection
in giant breeds such as Irish wolfhounds. lymph nodes. Lymph traverses the thoracic including fungal infections
or lymphatic ducts to reach the systemic • Infectious or immune-mediated skin disor-
RISK FACTORS venous circulation. ders with secondary edema
• Primary lymphedema is developmental in • Lymphatic diseases can affect specific organs, • Localized neoplasm
origin; diseases that obstruct, invade, inflame, as with intestinal lymphangiectasia (p. 600); • Myxedema (severe hypothyroidism)
or destroy normal lymphatics predispose to body cavities or regions, as with chylothorax;
secondary lymphedema. or the peripheral lymphatic system with Initial Database
• Lymphatic filariasis associated with infection resultant lymphedema. • Careful inspection of regional systemic veins
by Brugia pahangi is a consideration for • Malformation of the lymphatic system, • Auscultation over swellings for the bruit
lymphedema in tropical environments. lymphangitis, widespread obstruction to (continuous murmur) of an AV fistula
lymph drainage, or infiltration of regional • Rectal exam to identify caudal abdominal
Clinical Presentation lymph nodes can cause accumulation of or pelvic mass lesions
DISEASE FORMS/SUBTYPES high-molecular-weight protein and edema. • CBC, serum biochemical panel (with serum
• Localized involving a limb, intermandibular • Interstitial or subcutaneous protein accu- albumin), and urinalysis
space, or ventral thorax mulation exerts an osmotic effect, and fluid • Thoracic radiographs: evaluate for heart
• Bilateral pelvic limb or forelimb lymphedema accumulation can initiate an inflammatory disease, mediastinal mass, and pleural
• Generalized lymphedema (that can include reaction and tissue fibrosis. effusion
pleural or peritoneal effusions, including • Progressive accumulation of lymphatic fluid • Screening two-dimensional echocardiogram
chylothorax/chyloabdomen) leads to palpable swelling and impairs oxygen to exclude pericardial effusion, right heart
delivery, wound healing, and local resistance disease, or cardiac-related mass lesion
HISTORY, CHIEF COMPLAINT to infection. • Abdominal radiographs or ultrasonography:
• In primary lymphedema, the typical presen- • Gravitational forces and the tightness of the identify iliac lymphadenopathy, pelvic mass
tation is nonpainful, bilateral, and pitting skin influence the accumulation of tissue lesion, hepatosplenomegaly, or peritoneal
edema of the pelvic limbs. Generalized fluid lymph. effusion
retention is rare in dogs and cats. • Lymphedema can be varied, pitting, non- • Cytologic exam of regional lymph nodes or
• In secondary lymphedema, there is nonpain- pitting, or fibrotic in character. These are tissue fluid
ful or painful swelling of the limb(s), ventral well-recognized stages of lymphedema in • Biopsy of affected tissues to rule out
thorax, or intermandibular space. human patients and have been observed in lymphangiosarcoma, vasculitis, or atypical
• In generalized cases, respiratory distress can dogs or cats with chronic lymphatic diseases. (nonbacterial) infection
be related to pleural effusion. • Strictly speaking, lymphedema stems from
impaired lymphatic drainage. Subcutaneous Advanced or Confirmatory Testing
PHYSICAL EXAM FINDINGS edema can also be caused by reduced capil- • Duplex Doppler (simultaneous two-
• Nonpainful or painful swelling(s); persistent lary oncotic pressure (hypoalbuminemia), dimensional and Doppler ultrasound)

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