Glomerulonephritis in Cats

Glomerulonephritis is a serious medical condition that needs prompt care in order to prevent further kidney damage and complications from occurring. The disease occurs most often in older, male cats.

Glomerulonephritis is a type of kidney disease that occurs when the glomeruli in the kidneys become inflamed and dysfunctional. The glomeruli are small capillaries in the kidneys that act as filters for the waste products in the bloodstream. When the waste products are unable to be filtered, they build up in the bloodstream, causing illness and further kidney damage.

Symptoms of the disease can vary based on the cause of the glomeruli becoming inflamed and damaged. These symptoms include:

• Blood in the urine
• Protein in urine found in routine urinalysis
• Loss of appetite
• Weight loss
• Increased thirst
• Increased urination
• Nausea
• Vomiting
• Abdominal bloating
• Abdominal pain
• Breathing difficulties
• Frequent panting
• Weakness
• Lethargy
• Sudden blindness if blood pressure rises too high

A variety of chronic conditions can cause glomerulonephritis to occur. When the initial cause is unknown, the cause is considered to be idiopathic. Some possible conditions that can cause glomerulonephritis include:

• Heartworm infection
• Inflammation
• Cancer
• Diabetes mellitus
• Chronic periodontal (gum and tooth) disease
• Feline leukemia virus
• Chronic pancreatitis
• Neoplasia (growth of tissue or tumor)
• Feline infectious peritonitis
• Feline immunodeficiency virus
• Pyometra (bacterial uterine infection)
• Long-term use of drugs that harm the kidneys
• Endocarditis (bacterial heart infection)
• Chronically inflamed skin

The veterinarian will need to know the cat's complete health history, including a detailed list of all of the symptoms and when the symptoms first began. Because glomerulonephritis often doesn't display severe symptoms until over 75 percent of the glomeruli are damaged, the disease is often caught during routine exams.

The veterinarian will do a complete blood count, biochemical profile and a urinalysis. The complete blood count may show signs of anemia or a high white blood cell count from an infection, the biochemical profile may have high levels of the blood protein albumin and a urinalysis will have protein in it, which is typically not present in the urine made by healthy kidneys. The urinalysis may also contain proteins called hyaline casts, which indicates damage to the kidney tubules.

If the initial tests indicate that the cat may have glomerulonephritis, more specific labs and tests will be performed to confirm the diagnosis. A creatinine clearance test will compare the amount of a waste product called creatinine in the blood and urine. Too much in the bloodstream is indicative of kidney disease.

The veterinarian may use ultrasounds and x-rays to view the kidneys and surrounding abdominal organs. These tests are helpful in viewing the size of the kidneys, any tumors that could be causing the problems, and other disorders. A kidney biopsy can help the veterinarian identify the specific renal disease that is affecting the kidneys and to rule out other causes of the symptoms.

Successful treatment of glomerulonephritis depends on treating the underlying condition that caused the inflammation and glomerular damage to occur. 

Medication

Immunosuppressive drugs may be prescribed to the cat in order to suppress the immune system's response, preventing further glomeruli from becoming inflamed and damaged. Blood pressure medications called angiotensin-converting enzyme (ACE) inhibitors can keep the cat's blood pressure levels stable, reduce protein loss through the urine, and prevent further damage to the kidneys. A low-dose of aspirin may be given to prevent blood clotting and omega-3 fatty acid supplements may also be recommended in order to reduce inflammation in the cat's body. If glomerulonephritis has been caused by diabetes, insulin injections will need to be given several times a day in order for the cat to properly use the food it ingests as energy.

Surgery

Any tumors that are causing glomerulonephritis will need to be removed. The veterinarian will determine the best way to perform the surgery. Surgery is typically done in the hospital under general anesthesia. After the tumor has been removed, the immune system's response should be lessened, preventing further loss of glomeruli.

Specialized Diet

Because protein and sodium in the diet put additional strain on the kidneys, the veterinarian may recommend that the cat is placed on a low-protein and low-sodium diet. Eating a diet low in protein and sodium can help reduce the workload placed on the kidneys while the primary condition that caused glomerulonephritis is treated.

The cat will need to follow up with the veterinarian to monitor kidney function with blood and urine tests. Treatment for the underlying condition that triggered the immune system's response and damaged the glomeruli will need to occur. Though cats can live for a period of time with kidney damage, once kidney failure occurs, the prognosis is poor.