High Kidney Enzymes in Cats

Kidney disease is a common, chronic disease in elderly cats, although younger cats can be affected by it. In the case of younger animals the cause is usually genetic or as a direct result of a disease or toxin ingestion. Kidney disease is defined as the kidney's decreased ability to filter toxins from the blood and concentrate urine. Cats who exhibit symptoms of kidney disease will be tested by a veterinarian for the presence of increased blood enzymes that indicate the presence of kidney insufficiencies.

  1. Blood Urea Nitrogen (BUN)

    • One of the first values that are affected is BUN or blood urea nitrogen. This enzyme measures how well the kidneys are able to filter out specific toxins in the blood. As the kidneys become less efficient in filtering the blood, the blood urea nitrogen begins to build up in the bloodstream. This build up is measurable on a blood chemistry panel. The higher the level, the less function the kidneys have. However, BUN is not a good indicator of kidney disease by itself as there are other reasons BUN levels can be high, including dehydration.

    Creatinine

    • Another value that indicates the presence of kidney disease is creatinine. Creatinine is created when the muscles catabolize, meaning that creatinine is the byproduct of activity. High levels of creatinine in the blood indicate kidney insufficiencies, as this compound is filtered and eliminated by the kidneys. Creatinine levels are thought to be more specific when it comes to diagnosing kidney disease, however extended exercise and the onset of certain pituitary conditions may also increase creatinine levels in the blood.

    Other Blood Values

    • Other blood test indicators for kidney disease in cats include increased or decreased levels of calcium, phosphorus, potassium, and a host of other indicators. These in and of themselves will not diagnose kidney disease in cats, however the presence of skewed results for these indicators in the presence of physical symptoms and elevated BUN and/or creatinine levels will confirm the kidney disease diagnosis.

    Physical Symptoms

    • In most cases, cats will show the following symptoms when experiencing kidney disease: increased water consumption, increased urine production, lack of appetite, vomiting, weight loss, and fatigue. The hallmark symptom is water consumption and urine production. Cats are extremely efficient when it comes to conserving water, requiring them to only urinate a few times per day.

    Urine Tests

    • After a cat has been examined physically, the presence of symptoms noted and blood tests run, one of the final confirmation tests performed on a cat suspected to have kidney disease is a urinalysis. This test looks for the presence of glucose in the urine that would indicate that the physical symptoms and increased kidney enzymes could indicate diabetes instead of kidney disease. It also detects the presence of infection and tests the cat's ability to concentrate its urine. Dilute urine without the presence of glucose in the urine along with elevated BUN and creatinine levels generally confirms the diagnosis of kidney disease in cats.