Glomerulonephritis (GN) in Dogs

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Overview of Canine Glomerulonephritis 

Glomerulonephritis, commonly abbreviated as “GN”, is a disease of the kidney that can occur in dogs. The kidneys consist of many thousand microscopic filtering units called glomeruli that filter water and small substances from the bloodstream. The tubules of the kidney then reabsorb vital substances such as glucose and electrolytes from the filtered fluid leaving unneeded substances and a small amount of water in the urine.

Glomerulonephritis is inflammation of these microscopic filtering units of the kidneys that develops when immune complexes (complexes of antibodies and antigens) become trapped in the glomeruli, leading to activation of the body’s inflammatory defense system, which, in turn, damages the glomeruli. The immune complexes often form as a consequence of some other disease process such as infection or cancer. However, in many dogs with glomerulonephritis, the inciting cause cannot be found and the problem is said to be idiopathic.

Glomerulonephritis results in excessive loss of protein into the urine (proteinuria). The finding of protein in the urine on urinalysis may be the first indication that your pet has glomerulonephritis. Untreated, the disease can lead to chronic kidney failure.

Dogs of any age, breed or gender can develop glomerulonephritis. In many pets, there may be no obvious symptoms of glomerulonephritis.

What to Watch For

Signs of Glomerulonephritis in Dogs may include: 

  • Swelling of the abdomen
  • Swelling of the paws, hocks (ankles), face or scrotum
  • Increased water consumption
  • Increased urination
  • Weight loss
  • Lethargy
  • Vomiting
  • Sudden loss of vision
  • Sudden difficulty breathing
  • Diagnosis of Glomerulonephritis in Dogs

    Diagnostic tests are needed to identify acute glomerulonephritis and exclude other diseases. These may include:

  • Urinalysis to identify proteinuria or hyaline casts, which are protein molds of the renal tubules.
  • Complete blood count (CBC) to identify anemia, inflammation, infection or low platelet count.
  • Serum biochemistry tests to identify low blood protein concentration and high blood cholesterol concentration
  • Urine protein/creatinine ratio to determine the severity of protein loss in the urine
  • Blood pressure measurement to identify systemic hypertension
  • Kidney biopsy to identify glomerulonephritis conclusively and differentiate it from amyloidosis, which is another kidney disease that affects the glomeruli.
  • Treatment of Glomerulonephritis in Dogs

  • The ideal treatment for glomerulonephritis is to identify any underlying infectious, inflammatory or cancerous disease that may be causing production of immune complexes that are being trapped in the glomeruli. Unfortunately, in many cases of glomerulonephritis, no underlying disease process can be identified, or if one can be identified, it cannot be eliminated.
  • Immunosuppressive drugs can be administered to suppress immune complex formation. Drugs used for this purpose are cortisone-like drugs like prednisone) and the anti-metabolite drug called azathioprine. This is is not common practice as there has been no scientific evidence that this is beneficial in dogs.
  • A very low dose of aspirin may be prescribed to prevent clotting within the glomeruli.
  • Specialized diets may be used in some instances.
  • Low protein, low phosphorus diets should be given to pets in kidney failure.
  • Low sodium diets should be given to pets with hypertension.
  • Diets supplemented with omega-3 fatty acids to limit the inflammatory response.
  • Medications may be prescribed to control blood pressure in pets that are hypertensive.
  • Drugs called angiotensin converting enzyme (ACE) inhibitors like enalapril) may be used to minimize protein loss in the urine and to help control blood pressure.
  • Home Care and Prevention

    Administer as directed any medications prescribed by your veterinarian. Follow any dietary recommendations and schedule regular follow-up visits with your veterinarian to monitor your pet’s progress.

    Observation is important. Make sure your dog’s activity level, appetite and attitude remain normal. Watch for difficulty breathing or limb weakness that may indicate development of thromboembolism. Observe your pet for loss of vision that could indicate complications of hypertension. Look for swelling of the paws, hocks or face that could indicate development of subcutaneous edema and for swelling of the abdomen that could indicate fluid accumulation.

    Glomerulonephritis is difficult to prevent. Certain infectious, inflammatory and cancerous diseases can lead to development of glomerulonephritis and regular annual examinations by your veterinarian are advised to be certain your pet remains healthy and free of such diseases.

    In-depth Information on Canine Glomerulonephritis

    The kidneys filter water and small molecules from the bloodstream and into the renal tubules. Water and essential molecules are reabsorbed from the tubules and the remaining waste products and a small amount of water are excreted as urine. The microscopic filters of the kidney are called glomeruli (singular, glomerulus), which are small tufts of capillary blood vessels that act as a sieve, allowing small substances to pass through while keeping larger substances such as proteins and blood cells in the bloodstream.

    Glomeruli can be damaged by inflammation and become leaky. This is called glomerulonephritis. Very large things, such as red and white blood cells, still are not filtered but some substances not normally filtered like proteins leak through the inflamed glomeruli into the urine. The excessive loss of protein in the urine is called proteinuria, and this condition can adversely affect your pet’s health.

    Glomerulonephritis occurs when large numbers of immune complexes – these are antigen-antibody complexes – circulating in the bloodstream become trapped in the glomeruli as they attempt to pass into the urine. Deposition of immune complexes triggers an inflammatory reaction that damages the glomeruli and results in proteinuria. The antigens bound to the antibodies in the immune complexes arise as a result of some chronic infectious, inflammatory or cancerous disease process. Several diseases have the potential to result in glomerulonephritis.

    The clinical symptoms of glomerulonephritis are quite variable.

  • Affected dogs may have no symptoms at all. In this instance, glomerular disease first is suspected by the finding of proteinuria on a routine urinalysis.
  • Some dogs may have signs of chronic kidney failure such as poor appetite, lethargy, weight loss, poor hair coat, excessive urination and excessive water consumption.
  • Some dogs may have symptoms related to sudden blockage of major blood vessels by a blood clot (thromboembolism). Vessels commonly blocked include the lung arteries, which causes rapid breathing or panting, rapid heart rate and high body temperature, and iliac arteries, which causes sudden loss of use of the rear limbs. Thromboembolism is a medical emergency and your pet should be seen by a veterinarian promptly.
  • Some dogs may have symptoms related to systemic hypertension. Often the first symptom recognized is acute onset of blindness due to detachment of the retina or bleeding into the retina. This complication is a medical emergency and your pet should be seen by a veterinarian promptly.
  • Some dogs may have symptoms of an underlying infectious, inflammatory or cancerous disease process that predisposes the animal to glomerulonephritis.
  • Some dogs may have symptoms of subcutaneous edema, including swollen paws, face, hocks (ankles) or scrotum in males, or a swollen abdomen caused by fluid accumulation, known as ascites.
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