Excess Protein in the Urine in Cats

A diagnosis of proteinuria, or excess protein in the urine, may be alarming for cat owners, but a plan can be made with your veterinarian for your cat's long-term care and quality of life. A diet change is often required to ensure your cat's renal health.

Though it is easily diagnosed with a simple laboratory test, excess protein in the urine in cats can have a variety of causes that range from acute and treatable to chronic and merely manageable. Protein is filtered from the blood and the gastrointestinal system by the kidneys when they are fully functioning, and excess protein in the urine can indicate a potential renal problem. 

Often there are no symptoms or proteinuria, but there may be symptoms that are related to the underlying cause of the excess protein in the urine. Owners may notice a strong odor to the urine when there is a high level of protein present. An uncommon symptom of proteinuria that may also be present is hematuria, or blood in the urine. This may occur due to the strain that is being put on the kidneys or may be related to the underlying cause of the proteinuria. 

Types

• Acute proteinuria has a sudden onset and is typically caused by benign factors, such as a diet high in protein, or emergency reasons, such as kidney trauma or poisoning.
• Chronic proteinuria occurs when there is prolonged stress on the kidneys or progressive renal insufficiency.

Proteinuria is a condition with many potential causes that range in severity. If a cat is found to have proteinuria during routine testing or when an illness is suspected, the cause for the excess level of protein should be thoroughly investigated due to the potential for more serious problems. Though there are other possible causes for proteinuria, some more common ones include:

• Urinary tract infection
• Kidney infection or inflammation
• High-protein diet
• Hypertension
• Uncontrolled diabetes
• Parasites (such as lungworms and hookworms)
• Cancer of the bladder or kidneys

Excess protein in the urine in cats is diagnosed through urinalysis testing. The easiest way for a veterinarian to diagnose proteinuria is to obtain a sterile urine sample to perform a urine dipstick test on. The sterile sample is ideally obtained by cystocentesis, a process in which the veterinarian uses a long needle to obtain the sample from the bladder through the body wall. A sterile sample can also be gathered through urinary catheterization if the patient allows it. A drop of urine is then placed on each square of the test strip and is allowed to sit for the designated time for each test square. Protein levels, the presence of blood and the pH of the urine can all be checked for with the same dipstick test.

A ratio of the urine protein and creatinine levels can also be performed on the urine to determine the level of function that the kidneys have. If glomerular disease or other kidney disease is suspected, the veterinarian may recommend a biopsy of the kidneys to determine if there is a pathological cause for the low level of functioning.

To treat proteinuria, veterinarians must first treat the underlying cause for the condition. If an infection is present, antibiotics will be prescribed. Nonsteroidal anti-inflammatory drugs (NSAIDs) may also be prescribed in conjunction to treat inflammation. An uncontrolled disease such as diabetes or hypertension may cause proteinuria, and controlling the disease with medication is the best way to treat proteinuria in these instances.

Hospitalization with intravenous fluids may be recommended if the proteinuria is due to renal disease. Many cats with renal disease become so dehydrated that they do not want to eat and their other systems begin to shut down, so fluids are often used to increase hydration and replenish the body's electrolytes while also flushing the kidneys to cleanse them. Some cats will be prescribed subcutaneous fluids to be administered at home to continue to hydrate and cleanse the body.

Whether the cause for proteinuria is as simple as a high-protein diet or as complicated as renal cancer, a diet change may be recommended. A veterinarian may suggest a prescription diet that is designed for increased kidney function. 

The prognosis for a cat with proteinuria depends largely on the cause for the excess protein being excreted from the body. With the proper treatment for what is causing the proteinuria guided by a veterinarian, cats can live a healthy and fulfilling life. These cats should be regularly monitored with an annual or semi-annual urinalysis and blood work to ensure no progression of problems.

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