Systemic Lupus Erythematous (SLE) in Dogs
Inflammation of the lining of the chest cavity
Inflammation of the heart muscle or sac surrounding the heart
Enlarged lymph nodes
A complete blood count (CBC) may show anemia, low platelet count and low or high white blood cell count. If a regenerative anemia (one that shows evidence of response on the part of the bone marrow) is present without evidence of blood loss and with or without clumping of red blood cells on the slide (autoagglutination), a direct Coomb’s test is recommended to identify destruction of red blood cells by auto-antibodies. If anemia is non-regenerative, collection and microscopic evaluation of a bone marrow sample is recommended.
Results of serum biochemistry tests are often non-specific. A high blood globulin concentration may be observed as a manifestation of the inflammatory response. The presence of low serum albumin concentration and high cholesterol concentration may signal the presence of kidney disease characterized by damage to the microscopic filters of the kidney (glomerulonephritis).
Urinalysis may show proteinuria as a consequence of glomerulonephritis. Normal urinalysis results do not rule out the possibility of systemic lupus erythematosus.
Collection of joint fluid for microscopic analysis may show large numbers of white blood cells called neutrophils, absence of bacteria and moderate numbers of white blood cells called mononuclear cells.
The antinuclear antibody test (ANA) is considered the most sensitive and specific test to aid in the diagnosis of systemic lupus erythematosus. It is positive in up to 90 percent of cases, so a negative ANA does not always rule out the possibility of lupus. In dogs, there is no correlation between the amount of antinuclear antibodies present and the severity or course of the disease. Glucocorticoid therapy may cause false negative results on the antinuclear antibody test. False positive results may occur in dogs with cancer, chronic skin disease, or chronic bacterial infection.
The LE cell preparation is not as specific as the ANA test and is more commonly affected (rendered negative) by glucocorticoid treatment. This test detects the presence of white blood cells that have engulfed other cell nuclei that have been coated with auto-antibodies.
The microscopic pathology findings in skin biopsy specimens are characteristic of systemic lupus erythematosus and may be helpful in the diagnosis of this disease.
An immunofluorescence test to detect antibody deposition in tissues may show the presence of auto-antibodies of the types called immunoglobulin M (IgM) and immunoglobulin A (IgA). Another inflammatory protein component called complement (C3) also may be detected. This test may be positive in 50 to 90 percent of dogs with systemic lupus erythematosus.
Skin samples from the nose or footpads of normal dogs may show positive immunofluorescence results. Thus, these sites should be avoided when the immunofluorescence test is done. Treatment with glucocorticoids may cause false negative results.
Treatment In-depth for Systemic Lupus Erythematous in Dogs
Immunosuppressive treatment is required. It includes a combination of high doses of glucocorticoids (prednisone) and other immunosuppressive drugs (cyclophosphamide, azathioprine, chlorambucil). Therapy is life-long.
Prednisone is used at initial dosage of 1 milligrams per pound of body weight given twice daily for 10 to 14 days (induction period). After the induction period, the dosage is gradually tapered over a period of several weeks until an every-other-day regimen is achieved. Gastrointestinal ulcerations may complicate long-term administration of high doses of glucocorticoids. Dogs receiving high doses of glucocorticoids should be monitored for vomiting, diarrhea and loss of appetite. Complete blood counts are recommended every two weeks for the first few months of therapy to evaluate white blood cell and platelet counts.
Azathioprine (Imuran®) is used at a dosage of 1 milligrams per pound of body weight every day or every other day. Azathioprine can cause bone marrow suppression, liver disease and pancreatitis (inflammation of the pancreas). Bloody diarrhea also may occur in some instances. A lag phase of 6 to 8 weeks is necessary before the full effect of azathioprine is achieved.
Chlorambucil (Leukeran®) can be used in conjunction with glucocorticoids at a dosage of 0.1 milligram per pound of body weight every other day. It also has the potential for bone marrow suppression but may be safer than azathioprine. A lag phase of eight weeks is necessary before full efficacy of chlorambucil is achieved. Cyclophosphamide is another immunosuppressive drug of the same class as chlorambucil that can be used to treat systemic lupus erythematosus.
Gold salts also have been used to treat animals with immune-mediated disease. They should be avoided in dogs with kidney disease due to their potential for causing kidney damage and protein loss in the urine.
Prognosis of Dogs with Systemic Lupus Erythematous (SLE)
The prognosis for dogs with systemic lupus erythematosus is guarded and depends on the extent of kidney damage (glomerulonephritis) and the severity of anemia and thrombocytopenia (low platelet count). As many as 40 percent of dogs with systemic lupus erythematosus die within one year after diagnosis due either to the disease itself or to adverse effects of treatment.