What is Difference Between Renal and Kidney Failure

  • Author:

  • What’s the difference between renal and kidney failure?

    There is no difference; they are both the same thing, renal is another word for kidney.

    What are the abbreviations CRF, ARF etc.?

    CRF stands for chronic renal failure and means the disease is slow and progressive.

    ARF stands for acute renal failure and means that the disease has come on suddenly.

    What do the kidneys do?

    The kidneys perform several vital functions:

    • Filtering waste products from the blood
    • Regulates blood pH
    • Produces hormones that stimulate the bone marrow to produce red blood cells
    • Maintains the correct balance of certain minerals

    What is kidney failure?

    Kidney failure occurs when the kidneys are damaged, and they lose their ability to perform their functions efficiently.

    Chronic renal failure is slow and progressive. It is more commonly seen in older cats. The kidneys contain thousands of filtering units called nephrons; over time these become damaged and die. The kidneys compensate by increasing the size of the remaining nephrons. However, as more and more nephrons die, kidney function is compromised. When 70% of function is lost, you will notice symptoms of chronic renal failure. There are many causes of chronic renal failure including ageing, infections, and toxins. As the cat becomes older, the kidneys have had more exposure to the damaging effects listed above.

    Acute kidney failure occurs suddenly. Common causes include decreased blood flow to the kidneys (caused by heart failure, low blood pressure, blood loss), urinary tract obstruction, infection, poisoning, vasculitis (inflammation of the blood vessels).

    When the kidneys become damaged, they are not as effective at filtering the blood, which in turn leads to the build-up of toxins in the body. The kidneys also lose their ability to concentrate urine.



    The veterinarian will perform a complete physical examination of your cat and obtain a medical history from you. There are several medical conditions with similar symptoms, so a diagnostic workup will be necessary to diagnose kidney disease and determine the cause. 

    Diagnostic workup:

    • Biochemical profile: A test on the straw-coloured portion of the blood may reveal elevated BUN (blood urea nitrogen) and creatinine levels.
    • Urinalysis: Analysis of a sample of urine to evaluate the concentration of the urine.
    • Kidney ultrasound or x-ray to evaluate the size and shape of the kidney.
    • Kidney biopsy: A needle or wedge biopsy of the kidney is obtained under sedation or anesthesia via laparotomy or percutaneously. 


    There is no cure for kidney failure and treatment is aimed at medically managing the condition and supporting the kidneys. 

    • Fluid therapy: Cats with kidney disease are prone to dehydration, your veterinarian may show you how to administer fluids subcutaneously (under the skin) to manage dehydration. 
    • High blood pressure medications: Calcium channel blockers, beta-blockers, ACE inhibitors, and diuretics can reduce blood pressure by relaxing the blood vessels to reduce the resistance of blood flow. 
    • Prescription diet: These diets are moderate in protein and low in phosphorous
    • Phosphorous binders: As the kidneys are not as efficient at removing excess phosphorous from the body and levels can quickly build up. Phosphorus binders are medications that bind to some of the phosphorous in the food, to reduce the amount of phosphate in the blood. 
    • Anti-nausea medication: Maropitant (Cerenia) is an antiemetic (nausea) medication that is helpful in the treatment of nausea and anorexia in cats with kidney failure. 


    • Julia Wilson, 'Cat World' Founder

      Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio