Kidney Failure in Dogs: Signs, Stages and Treatment

What it usually means

The kidneys filter waste from the blood, balance water and salts, and help control blood pressure and red blood cell production. In chronic kidney disease (CKD), the Merck Veterinary Manual explains, the kidneys gradually lose that ability and waste builds up in the blood. It is most common in older dogs, and the AKC notes that small breeds often show early signs from around 10 years old, while large breeds may show them from about 7. Causes include aging, infections such as leptospirosis, kidney stones, inherited disease and cancer.

Acute kidney injury is different: a sudden loss of function, which may be partly or fully reversible if treated quickly. The AKC lists causes including antifreeze, grapes and raisins, certain medicines, infections, blocked urine flow, severe dehydration and heatstroke. Because the kidneys have a lot of reserve, the AKC says signs of chronic disease often appear only after about two-thirds of kidney tissue is damaged, which is why routine blood tests in older dogs are so useful.

Signs of kidney disease in dogs

The first sign is usually increased thirst and urination: emptying the water bowl faster, asking to go out at night, or accidents in a house-trained dog. As the disease advances, signs include a poor or fussy appetite, nausea, vomiting, weight and muscle loss, lethargy, dehydration, diarrhea, pale gums and breath that smells like ammonia. Some dogs develop mouth ulcers or high blood pressure, which can cause sudden blindness.

Acute kidney injury can look very different. A dog may suddenly become very sick within hours or days, with vomiting, refusing food, weakness, a painful belly and passing little or no urine. Increased thirst has many causes besides the kidneys, including diabetes, Cushing's disease and uterine infection, so testing is needed to know which it is.

When to call your vet today

Call your vet within a day or two if your dog is drinking or peeing noticeably more, has started having accidents, is eating less, losing weight or has new bad breath. Measuring how much water your dog drinks over 24 hours and bringing a fresh urine sample makes the appointment more useful.

Call the same day if a dog with known kidney disease stops eating, vomits, seems weaker or more tired, or if you notice blood in the urine. Small changes can mean the disease has moved to a new stage and treatment needs adjusting.

When it's an emergency

Go to your vet or the nearest emergency vet immediately if your dog may have swallowed antifreeze, grapes, raisins, lilies, rodent poison or human medicines, even if it seems fine. Treatment works best before kidney damage shows. Call ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661; a fee may apply. Bring the packaging with you.

Also seek emergency care for repeated vomiting, a dog that will not eat or drink, severe weakness or collapse, a seizure, or a dog that has passed little or no urine for 12 hours or more. A male dog straining with nothing coming out may have a blockage, which is life-threatening.

What you can safely do at home

Never restrict water for a dog drinking a lot; dogs with kidney disease rely on extra water to flush waste. Keep several bowls of fresh water available, give frequent toilet breaks, and track appetite, weight and urination. Keep antifreeze, grapes, raisins, medicines and household chemicals well out of reach.

Do not give human pain relievers, which can damage dog kidneys, or supplements and herbal remedies without your vet's approval. Do not switch your dog to a kidney diet or home-cooked food on your own; your vet will recommend a diet based on the stage of disease and your dog's other needs.

What the vet will likely check

Blood tests measure waste products such as creatinine and SDMA, along with phosphorus, potassium and red blood cells. A urinalysis shows whether the urine is dilute and whether protein is leaking through the kidneys, and a urine culture can rule out infection. Blood pressure measurement, X-rays and ultrasound may also be used. For chronic disease, vets usually assign a stage from 1, the mildest, to 4, the most severe, which guides treatment.

Acute kidney injury usually needs hospital care with intravenous fluids, treatment of the cause and close monitoring. Chronic kidney disease is managed over the long term with a kidney-support diet lower in phosphorus, control of blood pressure and protein loss, treatment of nausea and appetite, and sometimes fluids given under the skin at home. Merck notes that the main goals are comfort and controlling signs, and many dogs keep a good quality of life for months or years.

Prevention

You cannot stop kidneys from aging, but you can catch disease early and avoid preventable damage. Ask your vet about yearly blood and urine tests for dogs over about seven, or earlier for breeds with inherited kidney problems. Keep your dog well hydrated, especially in hot weather, and protect it from heatstroke.

Store antifreeze, medicines and rodent bait securely, never feed grapes or raisins, and discourage your dog from drinking from ponds, puddles and standing water, which can carry leptospirosis. Keep dental care up to date, and tell your vet about any increase in thirst rather than waiting for other signs.

This page is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your pet.