Article from VIN Associate

Article from VIN Associate for your information.

Often not an easy problem to determine. I would for sure aspirate the leg and the LN.

I hope there is something in here that helps you.

Lymphedema 
Last updated on 2/6/2015.

Contributors:
Revised by Kari Rothrock DVM, 2/6/2015
Original author was Linda G. Shell DVM, DACVIM (Neurology), 2/16/2004

Disease description:
Lymphedema is the abnormal accumulation of protein-rich lymph fluid in the interstitial space. Lymphedema may be primary or secondary.¹ Primary lymphedema occurs with developmental abnormalities of the lymphatic system. Secondary lymphedema arises from acquired disorders that result in abnormalities of the lymphatic system.²

Etiology and Pathophysiology
Lymphedema occurs when capillary filtration exceeds the resorptive capabilities of the venous and lymphatic system. This imbalance can be caused by overload of the lymphatic system; inadequate collection by the lymphatic terminal buds; abnormal lymphatic contractility; insufficient numbers of lymphatics; lymph node obstruction; and thoracic duct problems.³ In cases of primary lymphedema, aplasia or hypoplasia of the lymphatic vessels and valves; lymph node fibrosis; or decreased lymph node size and number can be present.² As edema progresses, the resulting high osmotic pressure pulls additional fluid into the interstitial space and worsens the edema. Collagen deposition and fibrosis occur with chronic lymphedema.³

Primary lymphedema may be idiopathic or hereditary. Secondary lymphedema can occur due to disorders that cause altered vascular permeability; damage or obstruction to the lymphatic vessels or nodes; or venous hypertension.¹ Lymphoproliferative disorders, neoplasia, filariasis, trauma, surgery, radiation therapy, congestive heart failure, heat exposure, and infection have all been associated with secondary lymphedema.^1,3

Diagnosis
Physical Examination Findings: Peripheral edema is the most common clinical sign associated with lymphedema. Edema is most common in the extremities (especially the hind limbs) and may be unilateral or bilateral.⁴ Less commonly, the ventral thorax, abdomen, ears, and tail may be involved. Initially the edema is pitting and nonpainful. Pitting is lost as fibrosis develops over time. Pain and lameness are not seen with lymphedema unless massive enlargement of the limb or cellulitis develop.⁴ In cases of congenital lymphedema, clinical signs are present at birth or develop several months later.¹ Peripheral lymph nodes may be small on palpation. Edematous areas are at increased risk for ulceration, drainage, trauma, and infection.²

Complete Blood Count (CBC)/Biochemistry Panel: CBC and chemistry panels are usually normal. Affected patients are not hypoalbuminemic.³

Fine Needle Aspirate and Cytology: Aspirates of edematous areas yield a low-cellular transudate.² The fluid is usually protein rich (2-5 g/dL).³ Increased numbers of leukocytes may be seen with secondary infection or inflammation.³

Lymphangiography: Radiographic lymphangiography can show lymph node aplasia and lymphatic vessels that end blindly in cases of primary lymphedema. In secondary lymphedema lymphatics may be enlarged and tortuous, and lymph nodes may be enlarged, with filling defects.²

Histopathology: Histology can be used to rule out other causes of edema and to detect morphological abnormalities of the lymphatic system that are consistent with lymphedema.²

Disease description in this species:
Lymphedema can be primary or secondary and is more common in dogs than in cats. Congenital, hereditary lymphedema has been reported in English bulldogs and poodles.^1,2 A possible breed predilection is reported for the Labrador retriever and Old English sheepdogs.¹ No sex predisposition has been documented.

Clinical Signs
Nonpainful, pitting peripheral edema is the classic sign of lymphedema. The hind limbs are most commonly affected. As edema becomes chronic, pitting no longer is present. Lameness and pain are typically absent unless marked enlargement of the limb or cellulitis occur.^3,4 Other clinical sings may be present depending on the underlying disease that is causing secondary lymphedema.

Etiology:
Congenital anomalies
Genetic, hereditary
Heart failure, right-sided
Idiopathic, unknown
Infection
Lymphangiopathy
Lymphangiosarcoma
Lymphatic obstruction
Lymphatic rupture
Neoplasia
Radiation
Surgical complication
Trauma

Breed predilection:
English bulldog
Labrador retriever
Old English sheepdog
Poodle

Sex predilection:
None

Age predilection:
Juvenile
Young adult

Images:

Click on each image to see a larger view

Figure 1A. Pitting edema in limbs This 5-month-old puppy had edema in three limbs since adoption. The edema had not worsened. A presumptive diagnosis of congenital primary lymphedema was made.

 

Figure 1B. Same puppy as in Figure 1A

 

Figure 2A. Congenital lymph edema of hindlimb Click here to see board discussion

 

Figure 2B. Congenital lymph edema of hindlimb Same puppy as in Figure 2A.

 

Figure 3. Congenital lymphedema Click here to see board discussion

Treatment/Management/Prevention:
SPECIFIC THERAPY
Recommended therapy depends on severity of the disease. No therapy may be required for mild cases.² Pressure bandages or splints can be applied to limit fluid accumulation and encourage lymphatic flow.^1,2

Benzopyrones, such as rutin and coumarin, have been used to treat experimental lymphedema in dogs.^15,16 Rutin reduces high-protein edema by stimulating macrophages to release proteases.¹ Doses of 50-100 mg/kg PO q 8 hrs have been suggested.^1,3

Surgical therapy has been used when conservative management fails but no surgical procedures are consistently beneficial. Lymphangioplasty, lymphaticovenous shunting, and lymphatic anastomosis have all been performed for lymphedema.^1,10 Amputation is a viable alternative for unilateral lymphedema.³

SUPPORTIVE THERAPY
Corticosteroids, fibrinolytic agents, and anticoagulants have been tried for lymphedema but have shown no real benefit. Diuretics are contraindicated since they increase protein content of interstitial fluid and can result in further fibrosis.^1,4 Topical skin care helps to prevent secondary complications, such as infection and ulceration. Antibiotic therapy is indicated if secondary infection is present.²

Any underlying disorder causing secondary lymphedema should be identified and treated appropriately.

MONITORING and PROGNOSIS
Lymphedema itself is not typically life-threatening. Puppies with severe, generalized lymphedema can die within the first few weeks of life, however. Prognosis for survival improves if an affected patient survives the neonatal period.² Some cases of lymphedema can spontaneously regress but edema does not typically resolve in affected dogs.¹ Lymphangiosarcoma has been associated with primary lymphedema in a few humans and one dog, but neoplasia in conjunction with primary lymphedema is rare in dogs.⁴

Preventive Measures:
Affected animals should not be bred due to the potential inheritable nature of primary lymphedema.⁴

Special considerations:
Other Resources:
Recent VIN Message Board discussions on lymphedema in dogs
Drug dosages for rutin and coumarin

Differential Diagnosis:
Cellulitis
Edema from hypoproteinemia
Edema from venous stasis: heart failure, cirrhosis
Lymphangitis
Lymphangioma
Lymphangiosarcoma
Lymphangiomatosis: diffuse or multifocal proliferation of lymphatics reported to occur rarely in the liver, skin and mammary gland of the dog
Neoplasia
Trauma

References:

Neoplasia seems unlikely in a

Neoplasia seems unlikely in a dog this age.

I had an older dog with a localized swelling that turned out to be Blasto.

The organisim was seen on cytology and the Blasto titer was high on a urine sample submitted to MiraVista Labs.

Just another thought