Understanding Kidney Disease in Cats and Dogs: Symptoms, Causes, Treatment and Care

A complete pet owner guide to signs, causes, diagnosis, stages, treatment, home care and prognosis

Key symptomsExcessive drinking and urination, vomiting, decreased appetite, low energy, diarrhea
CommonalityVery common in older cats, less common in dogs
TransmissionNot contagious
Impact on healthModerate to Severe depending on severity
Treatment cost~ $1,500 to over $5,000 AUD (depending on disease severity and treatment)
Treatment durationTypically life-long once medication is started
Ease of preventionMedium

Most affected dog breeds

Most affected cat breeds

Kidney disease in cats and dogs is one of the most common health conditions vets diagnose in older pets; here’s what every owner needs to know.

What Is Kidney Disease in Cats and Dogs?

Kidney disease in cats and dogs can develop suddenly as Acute Kidney Injury (AKI) or gradually as chronic kidney disease (CKD). Common signs include drinking and urinating more, vomiting, reduced appetite, weight loss and low energy. AKI can sometimes be reversed when treated quickly, while CKD is usually permanent but can often be managed with early detection, regular monitoring, a kidney-friendly diet, hydration and medication. Many pets continue to live comfortable, happy lives with the right ongoing care.

In this article, we explain the difference between acute and chronic kidney disease, the warning signs to look for, how vets diagnose and stage kidney disease, and the treatments that may help. We also cover kidney-friendly diets, hydration and home care, treatment costs and pet insurance, expected recovery or prognosis, and useful questions to ask your vet.

When the Vet Mentions "Kidneys": What to Know First

Dog and cat looking out a window, early signs of kidney disease in pets

Finding out your pet may have kidney damage can be a surprise, especially with the early signs being so subtle. A bit more time spent at the water bowl, a change in appetite, or more frequent trips outside or to the litter box may not seem like much at first. In cats, kidney changes are sometimes picked up on a routine blood test before you notice anything at home.

The kidneys do a lot of important jobs for your pet, their biggest job is acting like the body’s built-in filter and cleanup crew. They remove waste through urine while keeping useful things like water and electrolytes balanced. They also help regulate blood pressure and support red blood cell production, which all helps keep your pet feeling their best.

Infographic showing kidney disease risk statistics in cats and dogs by age

Getting older raises the risk of kidney disease, but so does the type of pet. It’s especially common in older cats, so vets usually recommend routine bloodwork for senior cats even when they seem perfectly healthy (prevalence rises sharply with age). Dogs face kidney disease too, smaller dogs tend to stay in the clear longer, often not showing signs until their early teens. Large breed dogs can run into trouble as early as age 7. There’s also a link between kidney disease and blood pressure that shows up especially in cats, once a cat is diagnosed, high blood pressure often follows, which is why vets tend to start checking it regularly from that point on. 

Vets can help, but they can’t reverse damage. Fluids and medications support the kidneys, yet tissue that’s already damaged usually stays that way. Early detection is what gives your pet the best chance at staying comfortable for longer.

Understanding the Two Types of Kidney Trouble; AKI vs CKD

When your vet says ‘kidney disease,’ they usually mean one of two things: acute kidney injury (AKI) or chronic kidney disease (CKD). AKI is a sudden drop in kidney function over hours or days, similar to a machine that suddenly jams. Similarly to clearing a jam, quick treatment can sometimes fix it. Meanwhile, CKD is a slow, usually permanent loss of working kidney tissue over months or years, more like a machine with parts wearing down one by one. Worn-out parts don’t repair themselves, and neither does this kind of kidney damage.

AKI and CKD symptoms can appear similar: tiredness, low appetite, vomiting. These signs are vague and aren’t specific to kidney trouble alone, so it’s best to get your pet checked rather than wait. Toxin exposure is one of the more common causes of AKI. Knowing which everyday foods and substances are harmful to pets can help you catch a potential emergency early.

Kidney Disease Symptoms in Cats and Dogs:

There are some signs that tend to point more clearly toward one or the other, shown in the table below:

Type What it means Example causes Some signs more specific to this type
Acute Kidney Injury (AKI) Fast decline in kidney function that may be partly or fully reversible Toxin exposure such as lily poisoning in cats, grape or raisin poisoning in dogs or severe dehydration Sudden collapse, not urinating at all, sudden and repeated vomiting, seizures
Chronic Kidney Disease (CKD) Slow, progressive loss of kidney tissue, usually irreversible Age-related decline, an inherited or breed-related kidney condition, or lasting damage from an earlier, untreated AKI Increased thirst, going to the bathroom more often, and in bigger amounts and gradual weight loss over weeks or months

Vets use history, exam, serial blood tests, and ultrasound to tell AKI from CKD and guide what the next steps for treatment are. A severe or untreated AKI can leave permanent scarring and increase the chance of your pet developing CKD later on, so acting quickly will make a difference in the long run.

When It Happens Fast: Treating Acute Kidney Injury in Cats and Dogs

Dog resting on a couch while recovering from acute kidney injury at home

If your pet has just been diagnosed with acute kidney injury, things probably happened quickly. Maybe they suddenly seemed unwell or you saw them eat something they shouldn’t, and now you’re overwhelmed at the vet trying to take it all in. That’s completely normal. Here’s what usually happens next.

Getting the Kidneys Back on Track: Treating Acute Kidney Injury

Earlier, we talked about how the kidneys filter out waste while holding onto water your pet needs. Both of those jobs depend on a steady flow of blood. When a pet is dehydrated or their blood pressure drops, that flow slows, and the kidneys struggle to keep up with either task. That’s why treatment usually starts with fluids given through an Intravenous drip, which corrects dehydration and gets blood moving through the kidneys again.

Your vet will also look for what caused the injury, whether that’s a toxin, an infection, or something else to treat directly. Any medications that could be hard on the kidneys are stopped right away.

Why Hospitalisation May Be Necessary

Acute kidney injury can change quickly in either direction, so pets are often hospitalized for close monitoring of blood values and urine output. Milder cases don’t always need hospitalization, but still need close monitoring, since even mild injuries can worsen fast.

Acute Kidney Injury Recovery and Outlook/ What Recovery from Acute Kidney Injury can Look Like

Here’s the reassuring part. Unlike chronic kidney disease, acute kidney injury can sometimes be reversed. Recovery can take days to months. For serious cases, that might include a week-long hospital stay. Some pets bounce back quickly, but a longer recovery time doesn’t mean a worse outlook. 

Even once your pet seems back to normal, their kidneys may not have fully recovered. Vets usually recommend ongoing monitoring, since some pets go on to develop the slower, chronic form of kidney disease.

From Suspicion to Diagnosis: How Chronic Kidney Disease Is Diagnosed in Cats and Dogs

Veterinarian examining a cat to diagnose chronic kidney disease

Not every kidney problem shows up as a sudden emergency. For a lot of pets, kidney trouble builds slowly, over months or even years. It’s often spotted first through annual bloodwork, or occasionally by chance through blood tests done before a procedure. This slow, ongoing type of kidney trouble is called chronic kidney disease, or CKD. Working out whether your pet has it usually starts with a handful of fairly simple tests.

Tests Your Vet May Do To Diagnose Kidney Disease

Vets have a few different tools for checking kidney health, and each one looks at something slightly different. The table below covers the main tests used and what each one tells your vet.

Test What It Checks Why It Matters
Blood test: Creatinine A waste product that builds up when kidneys filter less efficiently Rising levels can point to reduced kidney function, though by the time levels rise, a fair amount of kidney function has often already been lost
Blood test: SDMA Another substance in the blood that can rise even earlier than creatinine May flag kidney trouble sooner, sometimes catching it while kidney function is only partially reduced *Along with Creatinine, these are usually part of a standard blood panel. Run either in-clinic or at an outside lab
Urine test Checks how concentrated the urine is, and whether components are present that the kidneys would usually hold in When urine is diluted instead of concentrated, it suggests the kidneys aren't holding onto water properly. This often shows up alongside components escaping into the urine too *Concentration can be checked in-clinic; if protein levels need a closer look (UPC), the sample may be sent to an outside lab
Blood pressure Checks for high blood pressure High blood pressure can damage the kidneys, and kidney trouble can raise blood pressure, creating a cycle that makes both worse over time. Catching it early lets your vet step in with treatment to help slow that down *Quick and low-cost, can sometimes be done right there in the exam room
Imaging (ultrasound or X-ray) A look at the kidneys' size and shape Can reveal further clues about what's going on *Takes more time and costs more than the tests above, sometimes requiring sedation. Unlike the other tests which can be done during a standard consult, this may require an afternoon or day vet stay

Not every pet needs every test on this list. Your vet will tailor the order and combination based on what’s going on with your pet. If you’re ever unsure why a particular test is being run, just ask.

Why One Kidney Test Is Not Enough

Vets don’t usually rely on just one test done once. A single result can be thrown off by things like stress or mild dehydration on the day, so no single test tells the full story on its own. Combining blood work, urine tests, and blood pressure gives a clearer picture than any single result. That’s why some tests may be repeated over a week or two, to look for a consistent pattern rather than a one-off number. This isn’t a sign anything went wrong the first time. It’s simply part of how CKD gets confirmed properly.

What Happens After a CKD Diagnosis

CKD can usually be confirmed through testing. What’s harder to pin down is the cause, and for many cats, it’s never fully identified even with thorough testing. From here, vets use these same results to figure out how advanced the disease is, which we’ll cover next.

How Vets Measure the Progression of Chronic Kidney Disease (CKD) in Cats and Dogs

Stages of Chronic Kidney Disease in Cats and Dogs

Infographic of the four IRIS stages of chronic kidney disease in cats and dogs

Once CKD is confirmed, vets use something called the IRIS staging system to describe how advanced it is. Staging is based on numbers from bloodwork and blood pressure checks, not on how your pet looks or acts day to day. This is one of the main reasons ongoing monitoring matters so much, since the numbers can shift before you’d ever notice a change at home.

CKD is grouped into four stages, from earliest to most advanced. Your vet may also check for high blood pressure or protein in the urine, since both can affect how a stage is managed.



The Four IRIS Stages of Chronic Kidney Disease Explained

Stage What's Happening What You Might Notice at Home What Treatment Might Look Like
Stage 1 Kidneys are coping well overall, with only small changes showing up on bloodwork Often nothing noticeable, though very close attention might catch slightly increased thirst or slow, gradual weight loss Avoiding anything that could stress the kidneys further, plus regular monitoring
Stage 2 Kidneys are managing a heavier workload, and blood tests start to show clearer signs of reduced function Increased thirst and urination, sometimes mild vomiting or an upset stomach A kidney-friendly diet, keeping phosphate levels in check, and blood pressure monitoring
Stage 3 A significant portion of kidney function has been lost, and this usually shows up clearly in bloodwork More obvious signs, like poor appetite, vomiting, weight loss, and low energy More involved support, such as medication, fluids, and appetite support if needed
Stage 4 Kidney function is severely reduced Symptoms are usually hard to miss, such as ongoing vomiting, weakness, and noticeable weight loss Care shifts toward comfort and managing symptoms as closely as possible

A Kidney Disease Stage Is a Snapshot, Not a Countdown

It’s worth remembering that a stage isn’t a fixed sentence. Some cats stay in the same stage for a long time and barely progress. Staging simply helps guide the conversation with your vet about what to watch for and what support your pet might need next.

Staying Ahead of Kidney Disease: What's in Your Control (and What Isn't)

How to Reduce the Risk of Acute Kidney Injury

Some causes of acute kidney injury (AKI) can be avoided by keeping a few things out of reach:

  • Antifreeze
  • Grapes and raisins
  • Lilies
  • Human medications, especially pain relievers

Dehydration and untreated illness can also raise the risk, so prompt vet care when your pet seems unwell helps protect the kidneys too.

Can Chronic Kidney Disease Be Prevented in Cats and Dogs?

Chronic kidney disease (CKD) is different. It’s usually linked to age, and sometimes genetics, rather than something you could have avoided. Some breeds carry a higher genetic risk, but for most cats and dogs, CKD simply isn’t preventable in the way AKI sometimes is. 

What does help is catching it early. Routine vet visits and bloodwork, especially for older pets, can pick up changes well before symptoms appear. Early detection doesn’t undo CKD, but it gives you and your vet more room to slow it down and keep your pet comfortable for longer.

If your pet has already been diagnosed, this isn’t about anything you missed. Many cases are only found once they’ve progressed, and that’s not a reflection of how closely you were paying attention.

Building a Treatment Plan:The Veterinary Toolkit for Managing Chronic Kidney Disease in Cats and Dogs

Cat drinking from a water fountain as part of chronic kidney disease diet and hydration care

There’s no single treatment plan for chronic kidney disease. Every cat and dog is different, and what works well depends on the individual’s stage, symptoms, and how they respond over time. Think of it less as a fixed protocol and more as a toolkit that your vet adjusts as things change. The goal throughout is comfort and slowing progression, not a cure, since CKD can’t currently be reversed. Of everything in this toolkit, monitoring matters most, since it’s what tells your vet whether the rest of the plan is working.

Monitoring Kidney Function: The Most Important Tool

These are the same blood and urine tests mentioned earlier. They tell your vet whether the current plan is working, whether it needs adjusting, and whether the disease is progressing. Rechecks tend to happen more often as the disease advances, since closer monitoring is needed to stay ahead of changes:

  • Earlier stages: every three to six months, or sooner if problems come up
  • Mid to later stages: every two to three months

Kidney-Friendly Diets for Cats and Dogs

A kidney-friendly diet is one of the most effective tools available. These diets are typically lower in phosphorus and protein, which matters because both put extra strain on kidneys that are already struggling to filter waste. Reducing that load can help slow further damage and ease some of the symptoms caused by waste buildup in the body. Your vet can refer you to the available brands that suit your lifestyle and pet’s tastes.

Hydration Support

Encouraging your pet to drink more is part of everyday management. If your pet has a sudden flare-up, becomes dehydrated, or needs extra help flushing waste out of the body, fluids given through an IV at the vet may be needed to help stabilize things.

Medicines That Support the Kidneys

These medications are aimed at protecting the kidneys and slowing further damage. They include:

  • Blood pressure medication. High blood pressure puts extra strain on the kidneys’ delicate filtering system, so keeping it under control helps protect what function remains.
  • Phosphate binders. As kidneys struggle to filter properly, phosphorus from food can build up in the blood instead of being removed. These medications reduce how much phosphorus the body absorbs in the first place, easing that burden.

Other Supportive Medicines

As kidney function declines, other parts of the body can be affected too. This second group of medications addresses those wider effects rather than the kidneys themselves. They include:

  • Anti-nausea medication or appetite stimulants, since waste buildup in the blood can make pets feel sick or go off their food.
  • Support for low red blood cell counts, since the kidneys normally help the body produce new blood cells, and this process can slow down as kidney function declines.

Caring for a Cat or Dog With Chronic Kidney Disease at Home

Cat with chronic kidney disease resting comfortably by a sunny window

Managing CKD day to day looks different from a typical vet visit, and most of it comes down to small adjustments at home. This applies to cats and dogs alike, though a few of the day-to-day tactics look slightly different depending on which you have.

Switching to Kidney-Friendly Food

Once your pet is on a kidney-friendly diet, expect some trial and error. Cats especially can be picky about the change, so mixing the new food in gradually with the old tends to work better than switching all at once. It’s also worth budgeting for this as an ongoing cost, since prescription kidney diets are pricier than regular pet food.

Encouraging Your Cat or Dog Drink More

Pets with CKD often need extra encouragement to drink, and most owners find their own version of what works. Some ideas worth trying:

  • A water fountain, since a lot of cats prefer moving water
  • Extra water bowls placed around the house
  • Switching from dry food to wet, which naturally increases how much water your pet takes in through meals

Changes to Watch for at Home

Increased thirst and increased urination tend to be the first things owners notice in both cats and dogs, and usually the ones that worry them most too. A drop in appetite or energy is worth mentioning to your vet, even if it seems small.

You’re not alone in feeling like this is a lot. Many owners describe caring for a pet with a chronic illness as one of the more stressful parts of pet ownership. What’s realistic for one household isn’t always realistic for another, and that’s okay. If something on this list feels out of reach, whether that’s a specific diet, a particular routine, or anything else, talk to your vet about what’s manageable for you. A plan you can actually stick with is worth more than one that looks perfect on paper.

Kidney Disease Treatment Costs and Pet Insurance

Kidney disease isn’t a one-off expense. Whether it’s a sudden injury or an ongoing condition, costs can add up quickly, and with chronic kidney disease, they tend to grow over time. Early on with Chronic Kidney Disease (CKD), costs are modest, mainly monitoring and a prescription diet. As it advances, more frequent vet visits, medications, and imaging add up. A sudden crisis, whether that’s an acute injury or a flare-up on top of an existing condition, can add hospitalisation and IV fluids on top of routine costs.

Petsy has a record of cost range for treating kidney disease] Ongoing CKD management can run somewhere around $800 to $1,500 or more annually, depending on whether it’s a quieter year or one that includes a crisis. It’s a cost worth planning for particularly if you own a cat, since CKD is far more common in cats than dogs and becomes increasingly likely as they age. Some breeds carry extra genetic risk too, including Persian and Burmese cats, and Bull Terriers and English Cocker Spaniel among dogs.

This is where insurance fits in. Under a Petsy policy, kidney disease is covered as long as it first appears more than 14 days after your policy starts. If your pet already had signs of kidney trouble, or had already been diagnosed, before that point, it won’t be covered. Routine bloodwork done before any diagnosis is generally excluded as preventative care, along with prescription diets.

Once your pet is diagnosed, though, cover can make a real difference. This is where the bigger, ongoing costs sit: ongoing monitoring, treatment, and medications. It also matters most when things go wrong unexpectedly, like a flare-up or a crisis that needs emergency care.

The best time to think about cover is before any signs appear.

How Long Can Cats and Dogs Live With Kidney Disease?

It’s natural to want a number, but vets often can’t give one, and that’s not them avoiding the question.

  • Acute kidney injury: recovery can take days or months. Some pets bounce back further than expected, while others take longer despite the same treatment.
  • Earlier-stage CKD: pets often live well for years.
  • Stage 3 CKD: outlook varies, often somewhere around a year, sometimes longer.
  • Stage 4 CKD: time remaining is typically shorter, often weeks to a few months.

Individual pets regularly defy these general patterns in both directions. This is the kind of disease you take one step at a time, since how a pet responds to treatment and how quickly things progress are both hard to predict in advance. It’s less about finding a fixed timeline and more about seeing how your own pet does along the way.

Questions to Ask Your Vet About Kidney Disease

Most of this page speaks broadly, but every pet’s situation is different. These questions can help you understand your own pet’s specific situation.

  • What stage is my pet’s kidney disease at right now?
  • What specifically should I be watching for at home, given my pet’s stage and situation?
  • If applicable, how do the current medications or treatment currently help my pet and is there anything else to consider? 
  • How concerned should I be right now, and what would make you more concerned?
  • How often should we be rechecking bloodwork and urine tests for my pet?
  • Is my pet’s kidney disease stable, improving, or getting worse?

Kidney Disease in Cats and Dogs: Key Takeaways

A kidney disease diagnosis can feel like a lot to take in, but the outlook is often better than people expect, especially when it’s caught early.

  • AKI and CKD are different. Sudden kidney injury can sometimes be reversed with fast treatment. Chronic kidney disease is slower and permanent, but very manageable.
  • Early detection matters most. Routine bloodwork often catches CKD before you’d notice anything at home, and earlier stages mean more options.
  • A stage is a starting point for the conversation, not a timeline. Many pets stay stable for a long time with the right care.
  • Small changes at home go a long way. Diet, hydration, and a few adjusted habits are often just as important as medication.
  • You don’t have to get it perfect. A plan you can actually stick with beats one that looks ideal on paper.
  • You’re not in this alone. Your vet is there to help you figure out what’s next, one step at a time.

Kidney disease is common, especially in older cats, and most pets go on to live full, comfortable lives with a bit of extra care. Catching things early and staying consistent with the basics makes the biggest difference.

Kidney Disease in Cats and Dogs: Frequently Asked Questions

CKD itself usually isn’t described as painful, the way an injury or arthritis is. Any pain a pet with CKD experiences more often comes from a separate, concurrent illness. That said, the nausea and general unwellness from toxin buildup can still be uncomfortable.

No, CKD can’t be cured or reversed. Treatment can slow it down and ease symptoms, but the underlying damage stays. If bloodwork improves once your pet starts treatment, that’s a good sign the plan is working, not a sign the disease is gone. Ongoing management and monitoring are still needed even when things look stable.

They can look similar at home, both can cause more frequent urination, but they’re very different conditions. A UTI is an infection, usually treatable with antibiotics and rarely a long-term concern. Kidney disease is a decline in how well the kidneys themselves function, and it’s ongoing rather than something that clears up. The two can also happen at the same time, so if your pet is showing urinary changes, it’s worth having your vet check for both.

This is one of the hardest parts of caring for a pet with kidney disease, and it’s normal to feel overwhelmed by it. There’s no single sign that makes the decision for you. Vets generally look at whether your pet still has more good days than bad, whether they’re eating, and whether they still seem interested in the things they used to enjoy. Your vet can help you think this through, and you don’t have to figure it out alone.

These are some of the medical terms you might see on bloodwork or hear from your vet:

  • Creatinine: a waste product in the blood that builds up when kidneys aren’t filtering well.
  • SDMA: a newer marker that can pick up kidney trouble earlier than creatinine.
  • Azotemia: elevated levels of urea and creatinine in the blood, a sign kidney function is reduced.
  • Proteinuria: protein leaking into the urine, which can point to kidney damage. It’s part of why kidney diets are also lower in protein.
  • Phosphate (or phosphorus): a mineral that healthy kidneys help filter out. It can build up in the blood as kidney function declines, which is why kidney diets are formulated to be low in phosphate.
  • IRIS stage: a scale from 1 to 4 that vets use to describe how advanced kidney disease is, based on bloodwork and other results. IRIS (the International Renal Interest Society) is a group of kidney specialists whose staging guidelines are widely used by vets around the world.

This table covers a few of the more common ones, by active chemical ingredient, not their brand name. There are many other medications too, with different brand names, so your vet may prescribe something not listed here.

Medication What It's For
Amlodipine, Benazepril, Telmisartan Blood pressure control. High blood pressure puts extra strain on the kidneys, so keeping it down helps protect what function remains.
Benazepril Reducing protein loss in urine. Less protein leaking out means less ongoing damage to the kidneys' filters.
Lanthanum carbonate Phosphate binders. These stop excess phosphorus from food being absorbed, easing the burden on kidneys that can no longer clear it well.
Maropitant Anti-nausea. This doesn't treat the kidneys directly, but it helps with the nausea that toxin buildup can cause.

Each of these is only prescribed when bloodwork or other results actually show it’s needed. Giving a medication before it’s indicated isn’t just unnecessary, it can do more harm than good.

If your pet is on something not listed here, or you’re not sure what a medication is for, it’s always worth asking your vet directly.

Zara Knowles

Zara Knowles

Veterinary nurse and animal welfare graduate
Doctor of Veterinary Medicine, University of Sydney

Zara Knowles is a Sydney-based veterinary nurse and University of Sydney student majoring in Biology and Animal Health, Disease, and Welfare. She combines clinical experience with a part-time role in pet retail, having notably utilized Petsy Pet Insurance for feline health emergencies.

  • Veterinary Nurse at AMS Kingsford Veterinary Hospital since 2020
  • Hands on experience with dogs, cats, and wildlife including birds, reptiles, and possums
  • Special interest in feline medicine, shaped by clinical work and life with three cats

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