What Causes Kidney Failure in Dogs? Signs Like Blood in Urine

Name: What Causes Kidney Failure in Dogs? Signs Like Blood in Urine
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-02

Kidney failure in dogs happens when the kidneys lose their ability to filter waste, balance fluids, and make urine properly. The cause can be sudden (an infection, toxin, or blocked blood flow) or slow and long-term (age-related wear, inherited disease, or ongoing damage). This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Kidney failure is either acute (sudden, sometimes reversible) or chronic (slow, progressive, and not reversible).
Causes range from toxins, infections, and dehydration to age-related kidney damage and inherited conditions.
Blood in urine is not the most common kidney failure sign, so it often points to a urinary tract problem such as infection or stones, but it can appear with kidney disease too.
Diarrhea, vomiting, and loss of appetite are common because failing kidneys let waste build up in the blood.
Diagnosis relies on blood tests (creatinine and SDMA), urine tests, and staging, and treatment focuses on slowing damage and supporting the kidneys.

What Is Kidney Failure in Dogs?

The kidneys filter waste from the blood, control water and electrolyte balance, and help manage blood pressure and red blood cell production. When they fail, waste products like urea and creatinine build up in the bloodstream, a state called azotemia [1].

Veterinarians divide kidney failure into two broad types.

Acute kidney injury (AKI) develops over hours to days. Blood flow drops, or the kidney tissue is suddenly damaged. If the underlying cause is fixed quickly, some dogs recover kidney function [1].

Chronic kidney disease (CKD) develops over months to years. Damage builds up slowly, and the kidney cannot repair itself. Once the process starts, treatment aims to slow further damage, not reverse what is already lost [2].

Knowing which type your dog has changes everything about treatment and outlook.

Kidney Failure in Dogs Symptoms: What Owners Notice

Early chronic kidney disease often causes no obvious signs. That is why it is frequently found on routine blood work in older dogs [2]. When signs do appear, they tend to be vague at first.

Common signs include:

Drinking more water and urinating more often
Weight loss and muscle wasting
Reduced appetite or refusing food
Vomiting and diarrhea
Lethargy and weakness
Bad breath with an ammonia-like odor
Pale gums from anemia
Mouth ulcers

An 11-year-old dog in one case report showed up with three days of lethargy and poor appetite, and testing confirmed chronic kidney disease [3]. That pattern (tired, not eating, no dramatic symptom) is typical.

Where does blood in urine fit in?

Blood in urine is a red flag, but it is more often linked to problems in the bladder or urinary tract than to kidney failure itself. Infections, bladder stones, and inflammation commonly cause bloody urine. If your dog has blood in urine, see Dog Blood in Urine: Causes and Emergency Steps and Why Is My Dog having bloody urine? Cystitis Bladder Stones and UTI Guide. Kidney disease can also cause blood or protein to leak into urine, so your vet will test the urine to sort out the source [4].

Why does diarrhea happen?

Diarrhea shows up in kidney failure for a few reasons. Waste products building up in the blood irritate the stomach and intestines, which causes vomiting and diarrhea. Metabolic acidosis, a common complication of advanced kidney failure, adds to the nausea and GI upset [5]. Dehydration from diarrhea can also worsen kidney function by reducing blood flow to the kidneys [1].

If your dog is losing fluids through diarrhea, watch for dehydration. See Dog Kidney Disease: How to Tell If Your Dog Is Dehydrated.

What Causes Dog Kidney Failure?

Causes differ between acute and chronic disease. Some overlap, but the timeline and the treatment approach are different.

Causes of acute kidney injury

Toxins. Antifreeze, certain human medications (like NSAIDs), grapes and raisins, and some lilies and household chemicals can damage kidney tissue suddenly.
Infections. Bacterial infections like leptospirosis can attack the kidneys.
Reduced blood flow. Dehydration, shock, and congestive heart failure lower blood flow to the kidneys. This is called prerenal azotemia, and it often resolves once blood flow is restored, as long as the kidney structure is intact [1].
Urinary blockage. Stones or other obstructions that block urine flow back up pressure into the kidneys.
Medications. Some drugs are hard on kidneys, especially in dogs that are already dehydrated.

Causes of chronic kidney disease

Age. Kidney disease becomes more common starting around age 5 to 6 and affects up to 10% of elderly dogs [2].
Inherited or congenital problems. Some dogs are born with abnormal kidneys or a genetic tendency toward kidney disease [2].
Long-standing damage. Repeated infections, high blood pressure, or protein loss through the urine can slowly wear the kidneys down.
Unknown cause. In many older dogs, no single trigger is ever found. The disease is simply present and progressing [2].

Risk factors

A large retrospective study of over 16,000 dogs found that older age, male sex, being mixed-breed, eating homemade or mixed diets, and drinking tap or mixed water sources were linked to a higher risk of azotemia [6]. Living outdoors or in an indoor-outdoor setting was linked to lower risk in that same study [6]. These are associations, not proof of cause, but they are useful context.

How Veterinarians Diagnose Kidney Failure

Diagnosis starts with a history and physical exam. Your vet will ask about water intake, urination habits, appetite, weight changes, medications, and past illnesses [4].

Blood tests

Creatinine and BUN measure waste buildup in the blood.
SDMA is a newer marker that can rise earlier than creatinine in some dogs.
Chronic kidney disease is staged using creatinine and SDMA, measured on at least two occasions in a stable, hydrated dog after food has been withheld [1].

Urine tests

Urine protein-to-creatinine ratio checks how much protein is leaking through the kidneys. Dogs with chronic kidney disease should be substaged based on protein loss, ideally using at least two urine samples collected over two weeks or more [1].
Urinalysis checks for blood, infection, crystals, and concentration.

Other tests

Blood pressure measurement, since high blood pressure both results from and worsens kidney disease.
Imaging such as X-rays or ultrasound to look for stones, blockages, or abnormal kidney shape.
Blood gas and electrolyte panels to check for acidosis and mineral imbalances, which are common in advanced kidney failure [5].

Your vet may also check for complications like anemia and metabolic acidosis, both of which affect how your dog feels and how the disease progresses [3][5].

Treatment Options for Kidney Failure in Dogs

Treatment depends on whether the failure is acute or chronic, and how severe it is.

Acute kidney injury

The goal is to remove the cause and support the kidneys while they try to recover. Treatment may include:

Intravenous fluids to restore blood flow and flush waste
Stopping the offending drug or toxin
Antibiotics if infection is the cause
Relieving a urinary blockage
In severe cases, dialysis. One study of dogs with advanced renal failure used intermittent hemodialysis to correct acid-base problems and manage severe azotemia [5].

Chronic kidney disease

Chronic disease cannot be cured, but it can be managed. Treatment focuses on slowing progression and improving quality of life [2].

Prescription kidney diets reduce phosphorus and protein load on the kidneys.
Phosphate binders if diet alone does not control phosphorus.
Fluid therapy at home or in the clinic for dehydration.
Blood pressure medication if hypertension is present.
Medication for nausea, vomiting, and stomach ulcers.
Treatment for anemia if red blood cell counts drop.
Management of metabolic acidosis, which is common in advanced disease [5].

Your veterinarian calculates every medication dose based on your dog's weight, kidney values, and overall health. Never adjust doses on your own.

Recovery, Outlook, and Long-Term Management

The outlook depends heavily on the type and stage of disease.

Acute kidney injury has a real chance of recovery if the cause is caught and treated early. Prerenal azotemia often resolves completely once blood flow is restored, provided the kidney structure was not damaged [1].

Chronic kidney disease is progressive. Most dogs do not show signs until a large portion of kidney function is already lost, and existing damage cannot be reversed [2]. The goal is to slow further damage and keep your dog comfortable.

Staging matters for planning. Chronic kidney disease is classified into four stages using creatinine and SDMA, then substaged by protein in the urine and blood pressure [1]. Higher stages generally mean more intensive management. Your vet may also track newer markers. Lower urine ammonia-to-creatinine ratios have been linked to higher death rates and faster progression in dogs with stable chronic kidney disease [7]. Dogs with chronic kidney disease also show signs of insulin resistance and higher inflammatory markers, which may affect how they feel and how they are managed over time [8].

Practical long-term care includes:

Regular rechecks with blood and urine testing
Strict diet compliance
Fresh water always available
Monitoring for dehydration, vomiting, and appetite changes
Watching for new blood in the urine, which needs prompt evaluation

Prevention

Not all kidney failure can be prevented, but you can lower some risks.

Keep toxins out of reach. Antifreeze, human medications, grapes, raisins, and certain household chemicals are common culprits.
Never give human pain medications without veterinary guidance.
Keep your dog hydrated, especially during illness, heat, and after vomiting or diarrhea.
Treat infections promptly. Urinary tract infections and dental disease can affect the kidneys over time.
Schedule routine wellness exams with blood and urine testing, especially after age 5 to 6 when kidney disease becomes more common [2].
Ask about blood pressure checks at annual visits for older dogs.

Limitations and When to Contact a Veterinarian

This article covers general information. Every dog is different, and only a veterinarian who examines your dog and reviews test results can diagnose and treat kidney failure.

Contact a veterinarian the same day if your dog:

Stops eating or drinking
Vomits repeatedly or has ongoing diarrhea
Seems weak, wobbly, or unusually tired
Has blood in the urine
Drinks and urinates far more than normal

Go to an emergency clinic now if your dog:

Cannot urinate at all or strains with nothing coming out
Collapses or cannot stand
Has seizures or severe tremors
Breathes rapidly or has pale or white gums
May have eaten antifreeze, grapes, raisins, or another toxin

Schedule a routine visit if your dog:

Is an older dog due for blood work
Has gradually increased water intake or urination
Has lost weight without a diet change
Has been diagnosed with kidney disease and is due for a recheck

Frequently Asked Questions

Can kidney failure in dogs cause blood in urine?

Yes, it can, but blood in urine is more often caused by bladder infections, stones, or inflammation than by kidney failure itself. Your vet will test the urine to find the source. Any blood in urine deserves a prompt exam.

Is diarrhea a common sign of kidney failure in dogs?

Yes, diarrhea is a common sign, especially as the disease advances. Waste products and metabolic acidosis irritate the digestive tract and cause vomiting and diarrhea. Dehydration from diarrhea can also make kidney function worse.

What is the difference between acute and chronic kidney failure in dogs?

Acute kidney injury develops over hours to days and may be reversible if the cause is treated quickly. Chronic kidney disease develops over months to years, cannot be reversed, and is managed by slowing progression.

How do veterinarians confirm kidney failure in dogs?

Vets use blood tests for creatinine and SDMA, urine tests for protein and infection, blood pressure checks, and sometimes imaging. Chronic kidney disease is staged using at least two sets of blood tests in a stable, hydrated dog.

Can kidney failure in dogs be cured?

Acute kidney injury can sometimes be cured if the cause is removed early and the kidneys recover. Chronic kidney disease cannot be cured, but treatment can slow the damage and improve your dog's comfort and quality of life.

References

Renal Dysfunction in Dogs and Cats - Urinary System. Merck Veterinary Manual.
Noninfectious Diseases of the Urinary System in Dogs - Dog Owners. Merck Veterinary Manual.
Chronic kidney disease in a dog with hematologic and cardiovascular alterations: A case report. Open veterinary journal, 2026.
Detecting Disorders of the Kidneys and Urinary Tract in Dogs - Dog Owners. Merck Veterinary Manual.
Venous blood gas kinetics and acid-base correction during incremental intermittent hemodialysis in dogs with advanced renal failure. Veterinary world, 2026.
Risk Factors Associated with Azotemia in Dogs Presented to the Chiang Mai University Veterinary Teaching Hospital, Thailand: A Retrospective Study (2017-2021). Animals : an open access journal from MDPI, 2025.
Association of impaired ammonia excretion with survival in dogs with stable chronic kidney disease. Journal of veterinary internal medicine, 2026.
Exploratory analysis of insulin resistance and pro-inflammatory cytokines in dogs with chronic kidney disease. Domestic animal endocrinology, 2026.