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Body system: Kidneys and urinary tract. One of the core guides in our dog health conditions library. If your dog has worrying signs right now, start with our symptom triage guides.
Each kidney contains large numbers of tiny filtering units called glomeruli. Their job is to let water and waste pass into the urine while keeping useful protein, especially albumin, inside the blood. In glomerulonephritis, that filter is inflamed and damaged, most often because immune complexes, clumps of antibody and the material it has targeted, settle in the filter wall and trigger inflammation there. The damaged filter becomes leaky. Protein that should have stayed in the blood escapes into the urine, sometimes in large amounts, while waste handling can also deteriorate over time. The Merck Veterinary Manual describes immune complex glomerulonephritis as one of the most common glomerular diseases in dogs and identifies glomerular disease as a well recognized cause of chronic kidney disease.
Owners rarely see the filter damage itself. What they see are its effects, which can be subtle at first or absent altogether, because this condition is often found when a routine urine test shows persistent protein. As protein loss grows, a dog can lose muscle and weight, develop low blood albumin, and collect fluid in the legs or abdomen, a combination vets call nephrotic syndrome when it occurs together with high cholesterol. Protein in the urine also harms the rest of the kidney, raising blood pressure and increasing the risk of blood clots and progressive kidney failure. That is why a finding that can look minor on a lab report, protein in the urine on repeated tests, deserves a full workup and a long term plan rather than a wait and see approach. It is also worth knowing that glomerulonephritis is one member of a wider family of glomerular diseases, which also includes scarring of the filters and amyloid deposits, and that these conditions can look alike on routine tests while behaving differently over time. That overlap is why vets sometimes push for more detailed testing, including a kidney biopsy in selected dogs. For the owner, the practical message is simple: persistent protein in the urine is an early warning that arrives before a dog feels ill, and acting on it early offers the best chance to slow damage that cannot later be undone.
In many dogs no single trigger is ever found, and the disease is described as having no known underlying cause. When a cause is identified, it is usually a condition that keeps the immune system stimulated for a long time, so that immune complexes keep forming and lodging in the kidney filters. Long standing infections, including heartworm and Lyme disease, other inflammatory diseases, and some cancers are among the triggers vets search for. Inherited forms also occur in certain breeds and tend to appear earlier in life. A less common related pattern is amyloidosis, in which an abnormal protein is deposited in the filters. Identifying and treating any underlying trigger is a central part of care, because ongoing stimulation can keep driving the kidney damage.
Breeds and dogs at higher risk: Glomerular disease occurs most often in middle aged to older dogs of any breed, but inherited forms have been reported in Bernese Mountain Dogs, English Cocker Spaniels, English Springer Spaniels, Doberman Pinschers, Greyhounds, Lhasa Apsos, Poodles, Rottweilers, Samoyeds, Shih Tzus, and Soft Coated Wheaten Terriers, and these familial forms tend to start younger.
The starting point is proof that protein in the urine is persistent and is really coming from the kidneys. Your vet will repeat urinalysis, check the urine for infection, blood, and other causes of protein, and measure how much protein is being lost with a urine protein to creatinine ratio. The Merck Veterinary Manual notes that a ratio above 2 suggests, but does not prove, a glomerular source. Blood tests assess kidney values, albumin, cholesterol, and overall health, and blood pressure is measured because hypertension is a common complication. Your vet will also search for infections, inflammation, and cancer that could be driving the problem. A kidney biopsy is required to identify the exact type of glomerular disease, and it is most often discussed in severe, progressive, or nonresponsive cases.
Treatment combines care for the kidney itself with treatment of any underlying cause that testing uncovered, such as an infection or another inflammatory disease. For the protein loss itself, vets commonly use medicines that block the renin angiotensin aldosterone system, from the ACE inhibitor class or the angiotensin receptor blocker class, to lower pressure inside the filters and reduce the amount of protein leaking through. Blood pressure medicine is added if hypertension is present. Because heavy protein loss raises the risk of blood clots, an antiplatelet medicine may be prescribed as preventive care. Dietary change is another core part of the plan, usually a diet with moderated protein, reduced sodium, lower phosphorus when kidney values require it, and added omega 3 fatty acids.
In severe or progressive disease where a biopsy confirms immune complex glomerulonephritis, your vet may discuss immunosuppressive medicine to quiet the immune attack on the filters. The Merck Veterinary Manual notes that this type of glomerular disease is believed to account for approximately half of glomerular diseases in dogs, which is why immunosuppression is sometimes considered even when a biopsy has not been done, after weighing risks carefully. Treatment does not restore a scarred filter, and it should not be presented as a cure. The realistic goals are less protein loss, stable kidney values and blood pressure, and more good quality time.
Living with this condition means steady monitoring rather than dramatic daily care. Feed the therapeutic diet your vet recommends and avoid salty extras, give medicines at consistent times, and keep every recheck for blood work, urine protein measurement, and blood pressure checks, because dose changes are based on those trends. Watch appetite, weight, muscle condition, drinking, urination, and energy at home, and note any new swelling of the legs or abdomen, which can mean protein loss is worsening. Keep fresh water available at all times. Tell your vet about every other medicine and supplement your dog receives, because some common pain medicines can add strain to kidneys that are already leaking protein.
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A small, temporary amount can follow fever, exercise, or a urine infection, so vets look for protein that persists on repeated tests with a quiet urine sample. Persistent protein that comes from the kidneys signals a leaky filter. The urine protein to creatinine ratio measures how much is being lost and helps your vet track response to treatment over time.
Scarring and filter damage that have already happened cannot be reversed, so a complete cure is not a realistic promise. If an underlying infection or inflammatory cause is found and treated, protein loss can sometimes fall a great deal. In other dogs the goal is to slow progression, control blood pressure and protein loss, and maintain quality of life for as long as possible.
Urine and blood tests can show that the filters are leaking, but they cannot show which type of glomerular disease is present. A biopsy, examined with special techniques, can separate immune complex disease from scarring or amyloid deposits, and that distinction changes whether immunosuppressive treatment makes sense. Because biopsy carries bleeding risk and cost, vets reserve it mainly for severe or progressive cases.
It is the name for a pattern that can develop when protein loss is heavy: low blood albumin, high cholesterol, and fluid collecting in the legs or abdomen, together with large amounts of protein in the urine. Dogs with this pattern need prompt, close veterinary care because they face higher risks of blood clots, infection, and worsening kidney function.
Recheck timing is set by your vet based on kidney values, urine protein, and blood pressure, and visits are usually closer together after diagnosis or a medicine change. At each recheck the trend matters more than a single result. Stable protein loss and blood pressure are good signs, while rising protein, falling albumin, or new fluid buildup mean the plan needs adjusting sooner rather than later.
This page is general information drawn from the published guidance of the organizations listed under Sources below. It is not veterinary advice, and it does not replace your own veterinarian, who knows your dog. If your dog may have eaten something toxic, contact your veterinarian, the ASPCA Animal Poison Control Center on (888) 426-4435, or the Pet Poison Helpline on (855) 764-7661 straight away. A consultation fee may apply on the helplines. If your dog is struggling to breathe, has collapsed, is having a seizure that will not stop, or has a swollen belly with retching that brings nothing up, go to an emergency veterinarian now and do not wait to finish reading.
Last updated: November 2026. Facts on this page were checked against the sources listed above. How we work: our methodology.