Last Updated: 13/01/2026
Kidney Disease in Cats & Dogs: Signs, Causes & Management
Is your pet drinking more or losing weight? Kidney disease is a common condition, especially in seniors. Discover the difference between acute and chronic renal issues, the clinical signs to watch for, and how a prescription diet can help.
Author: Dr Teagan Lever BVSc (Hons)
Reading Time: 6 minutes - short read
The kidneys are the body's unsung heroes, working tirelessly to filter waste from the bloodstream and maintain a delicate balance of fluids and electrolytes. When these vital organs are damaged, they struggle to clear toxins, which can lead to a range of health issues for our furry companions. While a diagnosis of kidney disease sounds daunting, understanding the underlying causes and spotting the signs early can make a world of difference. Whether it is a sudden "acute" event or a gradual "chronic" change, there are many ways to support your pet and keep them wagging or purring comfortably for longer.
In this article
What is kidney disease in pets?
Kidney disease occurs when these vital organs lose their ability to effectively filter waste products from the blood and maintain the body's fluid balance.
In a healthy pet, the kidneys act as a sophisticated waste management system, producing urine to flush out toxins while keeping essential nutrients and water inside the body.
When the kidney cells become damaged and lose function, whether through age, genetics, or sudden illness, these toxins begin to build up in the bloodstream, often making your pet feel quite unwell.
Because the kidneys have a large "reserve capacity," pets often don't show visible signs of illness until a significant portion of their kidney function (about 75%) has already been lost, making early detection through vet check-ups a key part of proactive pet parenting.
Causes of acute vs chronic kidney injury
Kidney disease is classified as either acute or chronic.
Acute kidney injury
Acute kidney injury occurs suddenly, often in response to toxins, drugs, shock, infection, severe dehydration or urinary tract blockage. Once the cause is removed and proper treatment is provided, many pets with acute kidney failure can make a complete recovery.
Chronic kidney damage
Chronic, or long term kidney disease is defined as the non-reversible loss of functional kidney tissues over time. It may result from the same causes of acute kidney injury or it can also be caused by age-related loss of function, breed and hereditary factors as well as potential immune system problems.
Common signs of kidney disease to watch for
When the kidneys aren't working as they should, it sets off a "domino effect" in your pet's body. Here is a breakdown of what is happening behind the scenes:
- Difficulty staying hydrated: Damaged kidneys can't "concentrate" urine appropriately, meaning your pet loses too much water when they urinate. This leads to dehydration, which unfortunately makes the kidney damage even worse.
- Phosphorus buildup: Healthy kidneys keep phosphorus levels in check. When they fail, phosphorus builds up in the blood, acting like a toxin that speeds up the progression of the disease.
- Toxic waste accumulation: A major job of the kidney is to filter out waste from dietary protein. When this filter breaks down, these "uraemic toxins" stay in the blood instead of being urinated out. This is what causes nausea, vomiting, and lack of energy.
- Secondary health issues: Healthy kidneys also help to regulate blood pressure, so kidney disease can lead to high blood pressure and heart issues. Many pets also lose muscle mass and become quite thin; while the causes of this are complex, it’s usually a mix of a poor appetite and an imbalance in the blood's chemistry.
The signs of kidney disease are directly related to these impacts, and can include:
- Increased thirst
- Increased urination
- Loss of appetite
- Weight loss
- Vomiting
- Lethargy
If you notice any of these symptoms in your pet, check with your veterinarian. They can do blood and urine tests to check your pet's kidney function.
How is chronic kidney disease managed?
Unfortunately chronic kidney disease is a permanent and progressive condition that cannot be cured.
Treatment of chronic kidney disease is aimed at:
- Slowing the progression of the disease
- Reducing symptoms to improve your pet's quality of life
The role of nutrition in kidney health
The most critical part of treatment is the use of a veterinary prescription diet formulated specifically for pets with kidney disease. Prescription diets contain carefully controlled levels of high quality protein to reduce the levels of toxic waste products circulating in the blood stream. They also have reduced levels of phosphorus which can protect the kidneys from further damage and can increase life expectancy, particularly in cats.
Simple ways to increase your pet's water intake
Pets with chronic kidney disease are prone to dehydration, and increasing their water intake is important to counteract this and may also help to slow the progression of their kidney disease.
Along with making sure your pet has access to fresh water at all times, an easy way to increase your pet's water intake is to offer them the wet food varieties of the kidney diets. Providing a water fountain is also a great way to keep your loved one well hydrated, as many pets prefer running water!
Learn more about How to Increase Your Cat's Water Intake.
Why regular veterinary monitoring is essential
As chronic kidney disease is a progressive and life-long condition, regular check ups with your vet are essential for monitoring this disease as well as detecting any complications as soon as they arise.
Unfortunately chronic kidney disease can lead to other diseases such as high blood pressure and anaemia, and your veterinarian may prescribe medication to help manage these conditions.
FAQs
While a diagnosis of chronic kidney disease is a lifelong journey, it is one that can be managed effectively with a proactive approach. By combining a tailored renal diet with plenty of hydration and regular veterinary check-ups, you can significantly slow the progression of the disease. Every small adjustment, from a new water fountain to a specialised bowl of food, helps your pet feel their best and ensures you enjoy as many happy moments together as possible.
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Tue 13 Jan 2026
Edited by Dr Gillian Hill BVSc (Hons)Dr Teagan Lever BVSc (Hons)
Head Veterinarian, BVSc (Hons)
Pet Circle's Head Veterinarian, Dr Teagan graduated from the University of Queensland in 2010 and went on to work in small animal and mixed practice in various locations around QLD & ACT before joining Pet Circle in early 2016. Dr Teagan has special interests in dermatology, nutrition and preventative health care. She feels privileged to witness the special bond people share with their pets on a daily basis and enjoys forming lasting relationships with pet parents and their fur children.
