Kidney Disease in Cats: Our Vet Discusses Causes, Signs & Care

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Last Updated on November 23, 2023 by Catster Editorial Team

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	Dr. Iulia Mihai Photo

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Dr. Iulia Mihai

Veterinarian, DVM MSc

The information is current and up-to-date in accordance with the latest veterinarian research.

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Your cat’s two kidneys perform many vital functions in maintaining your pet’s health. They help eliminate toxins from the bloodstream (because they filtrate blood) and maintain water, electrolyte balance, acid-base balance, and blood pressure at normal values. They also regulate circulation and produce hormones (vitamin D, renin, and erythropoietin). When the kidneys stop working properly, it can lead to severe health problems that can put your cat’s life in danger.

Cat owners often become worried and confused when they hear that their cat has been diagnosed with kidney disease. Such a diagnosis is never easy. Early detection of the signs of kidney disease is crucial because they usually occur after 75% of kidney function has been compromised. The sooner your cat is diagnosed, the more you will be able to slow down the evolution of the disease. Since kidney disease generally occurs between 10 and 15 years of age, it is recommended that cats over 7 years be periodically evaluated.

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What Is Kidney Disease?

Kidney disease, also called kidney failure, is a condition in which the kidneys partially or completely lose their ability to function normally. It is a progressive disease in which the products of catabolism and toxic substances are no longer eliminated by the kidneys but retained in the body.

It most frequently affects elderly cats (over 12 years of age), being the most common cause of death.1 The disease develops over periods of months or years. Approximately 20–50% of cats older than 15 years have some stage of kidney damage.2 The frequency between the sexes is equal, though males are diagnosed at younger ages than females.

Kidney disease can be acute or chronic. Renal failure is defined as chronic when it lasts at least 3 months.

cat with kidney failure
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Acute Kidney Disease in Cats

Acute renal failure in cats is a condition with a sudden onset, resulting from a decline in renal function, which sets in within a few hours or days. As a rule, the first clinical signs are oliguria (the cat urinates less than usual) or anuria (the cat stops urinating).

This condition has multiple causes, such as obstruction due to urinary blockage or infection of the renal parenchyma (kidney tissue) and its functional units.

This type of kidney disease is reversible if the cause is recognized and treated in time.

Chronic Kidney Disease in Cats

Chronic kidney disease (CKD) or chronic renal failure is a condition in which the functional unit of the kidney, the nephron, loses its functionality.

When some of the nephrons are damaged, the others become overloaded, and in time, they will also be damaged. This leads to the inability of the kidneys to fulfill their functions of absorption and excretion, making it impossible to eliminate toxins from the body by filtering the blood and producing urine.

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What Are the Signs of Kidney Disease in Cats?

The clinical signs of kidney disease in cats are progressive and usually begin with an increase in thirst (polydipsia) and the amount of urine produced (polyuria). In general, the owner notices that their cat drinks more water and urinates more than usual. As the condition progresses and becomes chronic, the following signs appear:

  • Lack of appetite
  • Weight loss
  • Specific breath smell (ammonia breath)
  • Vomiting
  • Diarrhea
  • Pale mucous membranes
  • Anemia
  • Mouth ulcers
  • Dehydration
  • Matte fur
  • Increase in blood pressure

Death occurs due to uremia (uremic intoxication), which is when the toxic substances that should be excreted through the urine remain in circulation in such a quantity and time that the body can no longer survive.

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What Are the Causes of Kidney Disease?

The causes that can reduce the functionality of the kidneys in cats can be congenital or acquired, i.e., due to other diseases.

Certain breeds may be more prone to kidney disease:
  • Abyssinians, Siamese, Burmese, Tonkinese, Devon Rex, and Oriental Shorthair breeds are prone to amyloidosis.
  • Himalayan and Persian are prone to polycystic kidney disease, renal dysplasia, and unilateral renal agenesis (when a kidney is missing).
Here are the possible triggers that can lead to kidney damage:
  • Infectious diseases (viral or bacterial)
  • Inflammation
  • Secondary kidney infections (glomerulonephritis)
  • Cancer (e.g., lymphoma)
  • Certain nephrotoxic drugs, including human anti-inflammatory drugs (aspirin, ibuprofen, etc.), antifungals, and chemotherapy drugs
  • Other toxins, like antifreeze, toxic flowers (e.g., lily), pesticides, or cleaning products
  • Urinary blockage
  • Kidney stones
  • Thyroid problems
  • Advanced dental disease
  • Trauma (fracture of the pelvis, rupture of the urinary bladder, etc.)
  • Shock caused by massive blood loss or dehydration (e.g., car accident)
  • Heart failure with low blood pressure
  • Leptospirosis (transmitted through urine; humans can also be infected)

How Is Kidney Disease Diagnosed in Cats?

The diagnosis of kidney disease is usually established by blood tests—more precisely, by measuring urea and creatinine, products of metabolism that are eliminated through the kidneys. In general, these values start to increase from stage two. Chronic kidney disease has four stages, and the diagnosis is adapted according to them.

Other parameters that can be measured in kidney disease are as follows:

  • High levels of phosphorus usually indicate kidney damage.
  • Electrolytes (sodium, potassium, and chloride) often fluctuate between high and low levels.
  • Cats with CKD have low calcium levels.
  • The number of red cells can indicate kidney disease when it is low.
  • Symmetric dimethylarginine can be used for the early detection of kidney disease
  • The specific gravity of urine determines how diluted or concentrated it is; the higher the number, the more concentrated the urine
  • The ratio between urine protein and creatinine shows how much protein is lost in the urine.
  • A urine culture can detect urinary tract infections.
  • Cats with CKD have high blood pressure.
  • Abdominal X-rays or ultrasounds can detect kidney stones or areas of dead tissue.
devon rex cat examined by vet
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How Do I Care for a Cat With Kidney Disease?

If your cat has been diagnosed with kidney disease, you must follow the instructions of the veterinarian. Depending on the stage of the disease, they will also give you a prognosis:

  • Cats classified in stage two have an average life expectancy of 3 years (up to 8.5 years).
  • Cats classified in stage three have an average life expectancy between 1.8 and 5.7 years.
  • Cats classified in stage four have an average life expectancy of 1.16 months.

Also, cats with kidney failure that follow an adequate diet have a significantly longer survival time than those that do not consume a special diet.

The ideal diet should have a balanced intake of:
  • Proteins
  • Vitamin supplements
  • Antioxidants
  • Omega-3 fatty acids
  • Potassium

Alternatively, a homemade diet can be taken into consideration if it is formulated by a veterinarian expert in nutrition.

Don’t forget about water! A higher water intake (wet food and/or plenty of fresh water) helps cats suffering from kidney disease. You can also help your cat by reducing stress and administering subcutaneous fluids (on the advice of your vet).

To reduce stress, you can place more litter boxes and reduce the light intensity around the house. You can also use diffusers with feline pheromones and give your cat a place by a window where they can watch what is happening outside.

If the veterinarian recommends that you administer subcutaneous fluids to your cat, they will also teach you how to administer them. Subcutaneous fluids will help your cat stay hydrated by removing toxins from the blood. These can be administered daily or twice a week.

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Frequently Asked Questions (FAQ)

Do Cats With Kidney Disease Experience Pain?

Cats suffering from stage four kidney disease may experience pain, which may be due to oral ulcers, inflammation of the stomach lining, and the accumulation of toxins in the blood. They may experience headaches and collapse. Cats suffering from acute kidney disease may feel pain in the kidney area because the kidneys are inflamed. In other cases, when suffering from infections or urinary stones, they may feel pain when urinating.

Can Cat Kidneys Recover?

In chronic kidney disease, once the kidneys have been damaged, the recovery capacity is minimal. If early and adequate management of the disease is installed, it will evolve slowly, and your cat can have several years of quality life. In the case of acute kidney disease, the kidneys can recover if the condition is treated in time. Acute kidney disease is usually a reversible condition.

Do Cats With Kidney Disease Meow Frequently?

Excessive meowing is not a characteristic sign of kidney disease, but it can occur. Cats that feel sick and have pain or nausea may meow more than usual and become restless. If your cat suffers from kidney disease and meows excessively, take them to the vet. You can also place diffusers with feline pheromones in your home to eliminate stress.

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The diagnosis of kidney disease is usually severe. It is a progressive condition in which cats lose their kidney function. The average life expectancy of cats diagnosed with this disease is approximately 3 years. Due to the toxins that accumulate in the blood, cats will have a general feeling of sickness and nausea. They will also vomit and be dehydrated, and may even experience pain. If your cat is drinking more water than usual and urinating often, contact your veterinarian.

Featured Image Credit: Elpisterra, Shutterstock

About the Author

Dr. Iulia Mihai, DVM MSc (Vet)
Dr. Iulia Mihai, DVM MSc (Vet)
Iulia Mihai is a veterinarian with over 13 years of experience in pet pathology, laboratory, and cancer. She studied at the University of Agronomical Sciences and Veterinary Medicine of Bucharest, Romania (EAEVE member), where she worked in the laboratory of the faculty clinic after graduation. She has a master’s degree in equine and pet pathology and studied epithelial cancer for her Ph.D. Iulia has a passion for internal medicine and parasitology and started volunteering at the faculty’s clinic in her third year of college. She has worked in a couple of veterinary clinics over the years as an internal medicine specialist. She enjoys writing and teaching people about cat nutrition, behavior, and disease prevention and treatment.

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