Kidney Failure and Excess Urea in the Urine in Cats

Renal Failure and Acute Uremia in Cats

The sudden onset of abnormally high levels of urea, protein products, and amino acids in the cat's blood is referred to as acute uremia. This condition usually follows kidney injuries or occurs when the urinary tubes that connect the kidney to the bladder (ureters) are obstructed. As a result, the outflow of urine is obstructed, creating an imbalance in fluid regulation and leading to a buildup of potential toxins in the body. Fortunately, acute uremia can be successfully treated and cured if it is identified on time and treated promptly.

Most cat breeds, whether male or female, are affected by acute uremia; however, exposure to chemicals such as antifreeze increases the risk of uremia. Therefore, the incidence of acute uremia is higher in the winter and fall than in other seasons.

The condition described in this medical article can affect both dogs and cats. If you would like to learn how acute uremia affects dogs, please visit this page in the PetMD health library.

Symptoms and Types

As this potentially toxic blood flows through the cat's body, most systems are affected, including the urinary, digestive, nervous, respiratory, musculoskeletal, lymphatic, and immune systems.

Upon examination, cats will appear to be in normal physical condition, but may appear to be in a depressed state. When symptoms are apparent, signs can include loss of appetite, listlessness, vomiting, and diarrhea, which may be tinted with blood. Other symptoms may include inflammation of the tongue, ammonia-smelling breath (due to the urea), ulcers in the mouth, fever, abnormally fast or slow pulse, decreased or increased urine output, and even seizures. The kidneys may feel enlarged, tender, and firm on palpation.


Kidney failure or obstruction to urine output may be due to any of the following:

  • Kidney inflammation
  • Kidney or ureteral stones
  • Presence of foreign bodies in the ureter(s)
  • Damaged kidney tissue that causes back-flow of urine
  • Low blood flow to the kidneys as a result of trauma, excess bleeding, heat stroke, heart failure, etc.
  • Ingestion of chemicals (e.g., some pain killers, dyes used for internal imaging, mercury, lead, antifreeze)


A complete blood profile will be conducted by your veterinarian, including a chemical blood profile, a complete blood count, and a urinalysis. Cats with acute uremia may have high packed cell volume and an increased white blood cell count. The levels of certain protein enzymes and chemicals such as creatinine, phosphate, glucose, and potassium will also be high.

Urine may be collected by inserting a catheter or a fine needle aspiration into the cat; the results of which may show high levels of protein, glucose, and the presence of blood cells. In order to view and examine the urinary system clearly, contrast dyes may be injected into the bladder so that the interior of the bladder, the ureters, and the kidney are illuminated on the X-ray and ultrasonography imaging.

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