Causes of Proteinuria in Dogs

The cause of proteinuria dictates how it's treated.
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During your dog's regular vet exam, his lab work may have revealed a high amount of protein in his urine. Sometimes a high protein level can be attributed to diet, an easy fix. Other times, the culprit is proteinuria, a potentially serious condition requiring treatment. Determining the cause will dictate treatment.

Three Kinds of Proteinuria

There are three types of proteinuria, each with its own cause. Preglomerular proteinuria means there's an unusually high amount of small proteins, such as free hemoglobin, in the blood. The proteins are too small to be filtered and can't be absorbed into urine. In glomerular proteinuria the glomeruli, where the kidneys clean the blood, are damaged, allowing excessive protein into the urine. In post glomerular proteinuria, a high urinary concentration is the result of inflammation or tissue damage, such as from a bacterial urinary tract infection. Glomerular proteinuria is the most serious type of proteinuria.

Root Causes

If something isn't quite right in one part of your pup's body, it can affect his kidney function, leading to one of the three types of proteinuria. There are benign causes, including fever, stress, strenuous exercise and seizures. Problems with his urinary tract, such as kidney or bladder infections, can cause proteinuria. Other causes, varying in seriousness and not related to his urinary tract, include congestive heart failure, infections to include pneumonia and Lyme disease, inflammation such pancreatitis, Cushing's disease and steroids. The most serious cause of proteinuria is when the kidney's glomerulus is diseased, such as amyloidosis and glomerulonephritis, leading to glomerular proteinuria.

Different Types, Causes and Symptoms

One of the problems with proteinuria is that it's difficult to know your pup is suffering from it. Often there are no symptoms; however, when signs of the condition present, they reflect the type of proteinuria the dog has. Glomerular proteinuria usually doesn't show symptoms until it's very serious. Preglomerular proteinuria's symptoms include discolored urine and whatever symptoms accompany the root cause of the preglomerular proteinuria. The dog with post glomerular proteinuria may pee more frequently, strain and have pink or red urine.

Looking to the Lab for Answers

A urinalysis and blood work will help determine the presence of protein in the urine, as well as the type of proteinuria the dog has. A dog with preglomerular proteinuria will have high levels of protein in his blood; large amounts of albumin in the urine indicates glomerular proteinuria; post glomerular proteinuria shows evidence of urinary tract inflammation in the urine sediment. Treatment and prognosis depend on the type of proteinuria the dog is diagnosed with, and sometimes requires a change in diet.