Renal Failure Symptoms in Cats – A Quick Guide

Renal Failure Symptoms in Cats

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Our cat has a number of different illnesses, one of which is the early stages of Renal failure. She is 15 years old, so it is to be expected, unfortunately. She still acts like a kitten occasionally, but her illnesses do take their toll sometimes. Renal failure symptoms in cats can mean them drinking more often and, therefore, weeing more often, plus other issues.

I hope today that I can share with you the Renal failure symptoms in cats and also some technicalities of the disease. Of course, it goes without saying that if you notice anything unusual, you need to consult a vet in the first instance.


Kidney failure in cats is almost 7 times more common than in dogs


A cat’s urinary system contains 4 sections: the kidneys, ureter, urinary bladder and the urethra. It is influenced by hormonal regulation and this, in turn, regulates sodium and blood pressure in the system. Blood pressure is increased by the amount of sodium your feline friend has digested, and the amount of sodium will determine the levels of water retention in the body.


Renal Failure Symptoms in Cat on the stairs


Sodium reabsorption in the kidney is handled by a hormone called Aldosterone. If this increases, the reabsorption of water into the organ will also increase, especially if the antidiuretic hormone ADH also increases as this prevents diluted urine from being produced.

Impaired kidneys mean that the patient retains more fluid than is necessary for their body. Too much fluid can result in oedema of the limbs or fluid accumulation in body cavities and tissues – sometimes called “third spacing”.


Renal failure anatomy


Renal injury can be broken down into three parts:


  • Prerenal (occurs before filtration) – conditions such as dehydration, shock, or low blood volume (poor renal blood flow)


  • Renal – conditions of Acute Renal Failure (ARF) or Chronic Renal Failure (CRF):


    • ARF symptoms – enlarged kidneys, oliguria or anuria, and fast decline in kidney function. ARF can be caused by toxins, heatstroke, diabetes mellitus (DM) and other metabolic diseases.


    • CRF symptoms – elderly, dehydrated cats. Often they show a history of weight loss, excessive thirst and urination. Patients with CRF produce large amounts of urine. They have smaller kidneys compared to cats with ARF. CRF can be due to kidney infection or chronic poisoning of the organ. Nephritis can also cause CRF – a degenerative condition of the nephrons. Nephrons are the filtration units of a kidney. As the nephrons are gradually destroyed, the health of the cat gets worse.


  • Postrenal – lower urinary tract perforation or obstruction. Kidney stones may show in an obstructed ureter.

Renal failure anatomy


Renal failure may also be due to:

  • Pyelonephritis – a bacterial or yeast infection in the kidney


  • Polycystic renal disease – an inherited congenital condition where the renal pelvis is distended with urine. With time, the tissue becomes fibrotic.

Patients with renal injury should eat low protein diets as this reduces the effort asked of the kidneys.

Anaemia may also be seen as the kidneys produce the hormone Erythropoietin.


Stages of Renal Failure


Stages of Renal Failure


At The Clinic

Cats have to be monitored fully, and fluid therapy checked for urine output. Any fluid losses from vomiting or diarrhoea should also be calculated by veterinary staff. Staff are typically advised to place an indwelling urinary catheter to aid in accurate monitoring of your cat.

Minimum production should be 1-2 mL of urine per pound per hour. Below this level, additional therapy will be considered.

You may be advised that diuretics or medications are required to dilate the renal arteries, which in turn promote blood flow to the kidneys.


Mental State of Mind

A cat with renal failure should also be assessed for their mental state of mind as multiple organ dysfunctions could take place quickly if the kidneys deteriorate further. The cat should also be checked for uremic ulcers (oral ulceration caused by a high level of urea in the bloodstream). Many mouth rinses will be scheduled.

Veterinary staff should weigh patients every 12 hours. In severe cases, every 2-4 hours. Bodyweight assessment and fluid balance intervals may need to be increased as well.


Black cat



It is only natural that the kidneys start “misbehaving” as the cat grows into old age. However, renal failure can occur at any age due to poisons such as toxic plants or antifreeze ingestion as well as other causes.

Like humans, early detection will improve their survival and quality of life. We were advised to place two or three bowls of water, rather than just one, around different parts of the house so our cat would feel more comfortable drinking more often and lessen the risk of her running out of water. We also bought a high-quality cat litter which absorbs more urine, and we clean it out more often.

Then there are numerous veterinary-grade foods available. Cats with this disease need low protein nutrients and all the major players in this field (Royal Canin, Hills etc) all produce a “renal” food of some kind – biscuits, mousse, wet food etc.


Renal Failure Symptoms in Cats – A Quick Guide


Does your cat have renal failure? What symptoms did you notice initially? Do you know what stage they are at? Please comment below and share with your friends and family.