Kidney Disease in Dogs: Signs, Stages and Treatment

What it is

The kidneys filter waste from the blood, conserve water, make urine and keep minerals such as potassium and sodium in balance. Kidney disease means they are no longer doing those jobs well.

There are two main forms. Chronic kidney disease (CKD) develops slowly, over months to years, and is irreversible once clinically apparent, although it can be managed. Acute kidney injury (AKI) is a sudden drop in kidney function, often from a toxin, infection or reduced blood flow. AKI is more often reversible than CKD, but Merck notes that severe or repeated episodes can lead to chronic kidney disease.

The earliest sign of CKD is usually drinking and urinating more, such as a water bowl that empties faster or accidents indoors. Because kidneys have reserve capacity, signs often do not appear until about two-thirds of kidney function is lost. Later signs include poor appetite, weight loss, vomiting, lethargy, bad breath and mouth ulcers. Veterinarians use IRIS staging, from stage 1 to stage 4, to guide treatment and judge the outlook.

Causes and risk factors

What you can do at home

Fresh water must be available at all times for a dog with kidney disease, and IRIS warns that limiting water is dangerous. If your vet prescribes a kidney diet, introduce it gradually over several weeks, and do not switch to a homemade diet without veterinary guidance, since these are harder to balance.

Watch appetite, weight, drinking and vomiting, and report changes. Keep recheck appointments and blood tests. Some dogs get fluids under the skin at home, which your vet will teach you if it is right for your dog.

Protect the kidneys. Keep antifreeze, human medicines and grapes and raisins out of reach, and never give human pain medicines to a dog. Merck lists antifreeze, anti-inflammatory drugs and grapes or raisins as causes of sudden kidney injury. Protect your dog from heat and dehydration as well.

If you think your dog swallowed antifreeze, grapes, raisins or a human pain pill, treat it as an emergency. Call your vet or an emergency clinic right away, or in the US call ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661 (fees may apply). Outside the US, contact your local emergency vet.

What happens at the vet

Diagnosis starts with blood work and a urine test. Blood tests measure waste products such as creatinine and a newer marker called SDMA, plus phosphorus and electrolytes. A urine test checks how well the kidneys concentrate urine, which is often the earliest change, and looks for protein. Your vet may also check blood pressure and take X-rays or ultrasound.

The results allow IRIS staging for CKD, which guides treatment. Care is tailored to the dog and typically includes a therapeutic kidney diet, low in phosphorus with modest high-quality protein, which Merck recommends from stage 2 onward. Other tools include phosphate binders, medicines for nausea and appetite, blood pressure control, treatment for protein loss and anemia, and fluids by IV or under the skin. Dialysis is available for dogs only in some cases, and kidney transplants are rare.

AKI is treated in the hospital, with carefully adjusted fluids, close monitoring of urine output and treatment of the cause. Merck reports that severe AKI needing medical intervention has a survival rate of about 50 percent.

For CKD there is no cure, but with good care many dogs live for months or years. IRIS says some live several years, though survival time varies widely and cannot be predicted with certainty.

Prevention

You cannot prevent all kidney disease, but you can lower some risks and catch it early.

Start with toxins. Keep antifreeze locked away and clean up spills, and keep grapes and raisins out of reach. Never give human anti-inflammatory pain medicines to a dog, since they can injure the kidneys.

Protect your dog from dehydration and heat. Always have fresh water out, and keep your dog cool in hot weather.

Schedule regular checkups, and for older dogs include bloodwork and urinalysis. The AKC and IRIS both say regular blood tests can catch kidney problems before outward signs appear, and early detection matters because the more advanced the disease, the poorer the outlook.

See your vet at the first sign of changes such as drinking more, and our page on excessive thirst lists other possible causes. Ask your vet about managing conditions such as urinary infections, stones and high blood pressure, which can affect the kidneys.