Proteinuria in Dogs

Proteinuria (Excessive Protein in Urine) in Dogs

By: Dr. Mary Anna Labato

Section: Information In-depth

The kidneys are responsible for maintaining fluid and mineral balance in the body. WaterFresh Flow Pet Fountain
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When glomeruli are damaged they can become leaky. When red and whiteCrystal Eye 4oz
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Glomerular proteinuria may be divided into selective and nonselective proteinuria. With selective glomerular proteinuria large amounts of albumin are lost through the glomerulus.

It results from a number of disorders but primarily from immune-mediated diseases and amyloidosis. The causes of nonselective glomerular proteinuria are the same as with selective glomerular proteinuria but results in a more severe proteinuria with loss of globulins, fibrinogen, antithrombin III (which is responsible for preventing blood clots) as well as albumin.

Diagnostic Testing In-depth

  • When a positive reaction for protein is detected on a routine urinalysis, the urine sediment should be evaluated

  • If pyuria (white blood cells in urine) is present then culture the urine to determine which type of bacteria is present

  • If blood is present in the urine look for causes of hemorrhage

  • If positive for blood but no intact red cells are seen consider hemolysis (red blood cell destruction). A positive blood test can also indicate hemoglobin or myoglobin in the urine

  • If casts of kidney tubules are seen, a disease of the kidney should be considered

  • Perform a urine protein/creatinine (U P/C) ratio. Measures the amount of protein and creatinine in a single sample. The U P/C of a single random urine sample from dogs with normal and abnormal glomerular function correlates with a 24 hour collection determination. A ratio greater than 1 is considered abnormal.

  • A 24 hour total urine protein quantification can also be performed by collecting all the animal's urine over a 24 hour period. In general, urine protein excretion values less than 30 mg/kg/day can be considered normal for cats and dogs.

  • Once proteinuria is confirmed obtain a complete blood count (CBC) and serum biochemistry profile
  • If the blood albumin level is decreased suspect glomerular disease

  • Blood pressure determination is important to identify systemic hypertension (high blood pressure)

  • Clotting profile and antithrombin III levels are performed to determine if the pet is at risk for bleeding problems or at an excessive risk for developing a thromboembolus (blood clot)

  • Kidney biopsy ultimately is needed to identify glomerulonephritis from amyloidosis

    For more information, please read glomerulonephritis.

     
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