Canine Glomerulonephritis
Glomerulonephritis is inflammation of the microscopic filtering units of the kidneys known as glomeruli. The inflammation develops when immune complexes, sucg as antigen-antibody complexes, become trapped in the glomeruli. This leads to the activation of the body's inflammatory defense system, which, in turn, damages the glomeruli. However, in many dogs the triggering cause is often cannot be determined. In such cases. glomerular disease is referred to s idiopathic.
Diseases Associated with Glomerulonephritis in Dogs
Recent evidence indicates that immune complexes from in glomerullar capillary wall in dogs with glomerulonephritis associated with dirofilariasis (heartworm disease).6
Leakage of plasma proteins, principally albumin, across the damaged glomerular capillary walls results in persistent proteinuria (presence of protein in the urine), the clinicopathological hallmark of glomerulonephritis. Recent evidence suggests that, in addition to being a marker of disease, persistent proteinuria is associated with progressive lesions and loss of additional nephrons (kidney cells).
Examination of the pedigrees of related affected Bullmastiff and Beagle dogs yields evidence supporting an autosomal recessive mode of inheritance.
Signs of Canine Glomerulonephritis
The diagnosis is made based on the presence of protein in the urine. Affected dogs usually exhibit weakness, listlessness, loss of appetite, and general depression. Vomiting, diarrhea, excessive thirst and urination, excessive urination at night (nocturia) and oral ulcerations are commonly present. High blood pressure is often seen in dogs with acute or chronic glomerulonephritis.
Treatment of Canine Glomerulonephritis
The generation of immune complexes depends on the presence of antigen. Hence, the most important therapeutic approach for glomerular disease is the identification and treatment of underlying diseases. Heartworm disease, ehrlichiosis, Lyme disease, and systemic lupus erythematosus are examples of treatable diseases that may cause glomerulonephritis. However, because the underlying disease is sometimes hard to identify or impossible to eliminate, immunosuppressive drugs are used to reduce the formation of the immune complexes. In cases when the cause cannot be determined, angiotensin-converting enzyme inhibitors have been shown to decrease proteinuria and potentially slow disease progression.
Supportive therapy is important in the management of dogs with glomerulonephritis and aimed at decreasing high blood pressure, edema and lowering the risk of formation of blood clots. High-quality, reduced-protein diets are recommended.6
If goes untreated, the disease can result in chronic kidney failure. In fact, glomerulonephritis is thought to be one of the major causes of chronic kidney failure.6
Adapted from:
1. Canine glomerulonephritis: new thoughts on proteinuria and treatment. Grauer GF. In: J Small Anim Pract. 2005 Oct;46(10):469-78
2. Familial glomerulonephropathy in the Bullmastiff. Casal ML, Dambach DM, Meister T, Jezyk PF, Patterson DF, Henthorn PS. In: Vet Pathol. 2004 Jul;41(4):319-25
3. Glomerulonephritis associated with simultaneous canine adenovirus-1 and Dirofilaria immitis infection in a dog. Sánchez-Cordón PJ, Salguero FJ, Núnez A, Gómez-Villamandos JC, Carrasco L. In: J Vet Med B Infect Dis Vet Public Health. 2002 Jun;49(5):235-9
4. Familial glomerulonephropathy in a litter of beagles. Rha JY, Labato MA, Ross LA, Breitschwerdt E, Alroy J. In: J Am Vet Med Assoc. 2000 Jan 1;216(1):46-50, 32
5. UC Davis Book of Dogs: The Complete Medical Reference Guide for Dogs and Puppies. Mordecai Siegal, Jeffrey E. Barlough
6. Small Animal Internal Medicine. Richard W. Nelson, C. Guillermo Couto (2005)
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