Kidney Infections in Dogs

Jennifer Coates, DVM
By Jennifer Coates, DVM on May 12, 2023

In This Article


What Are Kidney Infections in Dogs?

Kidney infections are just what they sound like—infections, almost always caused by bacteria, that primarily affect the kidneys. Kidney infections are not all that common, but any dog that has a history of bladder infections is at increased risk. The infections can affect dogs of all ages but are diagnosed more often in females that are middle-aged or older.

Kidney infections are very serious. Severe infections or even milder, chronic infections can seriously damage the kidneys and eventually lead to kidney failure. If you think your dog might have a kidney infection, make an appointment with your veterinarian as soon as possible.

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Symptoms of Kidney Infections in Dogs

Initially, dogs with kidney infections may not have many symptoms. They may seem just a bit “off.” As time goes on, however, more signs typically develop, including:

  • Lethargy

  • Poor appetite

  • Fever

  • Abdominal pain

  • Increased thirst and urination

  • Blood in the urine

  • Straining to urinate

  • Urinating inside the house

  • Urinating frequent small amounts

  • Vomiting

  • Weight loss

Causes of Kidney Infections in Dogs

Most kidney infections start in the bladder and are caused by bacteria that have traveled up a  dog’s urethra (the tube connecting the bladder to the outside world). Bacteria that are found in feces are most often to blame for bladder and kidney infections.

The urinary tract has many natural defenses against infection, but health problems can break down those defenses.

  • Chronic kidney disease—The inflammation and dilute (watery) urine associated with chronic kidney disease make urinary tract infections more likely.

  • Anatomic abnormalities—Some dogs are born with anatomic abnormalities that predispose them to urinary tract infections. For example, when a ureter (the tube that normally connects a kidney to the bladder) drains into the urethra, bacteria can more easily travel up to the kidney.

  • Urinary stones—Stones damage the inner surface of the urinary tract and make it more susceptible to infection.

  • Diabetes—Dogs with diabetes have dilute urine that contains sugar, which is an ideal breeding ground for bacteria.

  • Cushing’s disease—The high cortisol levels associated with Cushing’s disease suppress the immune system and create dilute urine, which increases the chances of infection.

  • Urinary tract cancer—Tumors within the urinary tract can lead to bleeding, inflammation, and anatomic abnormalities that all make infection more likely.

  • Immunosuppressive medications—Dogs who are on medications that suppress the immune system are at increased risk of infection.

These types of underlying health problems make kidney infections more likely, but sometimes kidney infections seem to appear out of nowhere.

How Veterinarians Diagnose Kidney Infections in Dogs

Any dog that might have a kidney infection should be checked by a veterinarian. The doctor will start by asking questions about your dog’s overall health and the symptoms you have been seeing at home. They will then perform a physical exam and probably recommend some basic lab work including a complete blood cell count (CBC), a blood chemistry panel, and a urinalysis to look for signs of infection and check your dog’s kidney function.

When a dog has a urinary tract infection, it can be difficult to figure out if it involves only the bladder (most common) or if the kidneys are involved as well, a rare but more serious condition. Abdominal X-rays may show kidney enlargement or other problems, but an ultrasound is the best way to look for evidence of infection in the kidneys.

Veterinarians will often collect urine with a sterile needle and syringe directly from a dog’s bladder or even from their kidneys, using ultrasound as guidance. The sample can be sent to the lab for culture and sensitivity tests—growing any bacteria that are present and then testing various antibiotics against them to see which will work best to treat the infection.

Treatment of Kidney Infections in Dogs

There are no home remedies for kidney infections in dogs. Prescription antibiotics are an essential part of treatment. Veterinarians will first pick an antibiotic that is likely to work well but may make a change based on the results of the dog’s urine culture and sensitivity test.

Commonly prescribed antibiotics include:

Dogs that aren’t feeling too bad may simply be sent home to take oral antibiotics. More severely affected dogs may need to be hospitalized so they can get antibiotics by injection, fluid therapy, and any other needed treatments.

Recovery and Management of Kidney Infections in Dogs

Most dogs with kidney infections require 10–14 days of antibiotic therapy. As long as your dog seems back to normal, your veterinarian may wait one to two weeks after treatment has stopped to perform a recheck to ensure all signs of the kidney infection are gone.

Preventing Kidney Infections in Dogs

Most kidney infections start out as bladder infections, so the best way to prevent kidney infections is to treat bladder infections quickly and completely. Have your dog seen by a veterinarian if you notice any of these signs of a bladder infection:

  • Discomfort when urinating

  • Urinating frequent small amounts

  • Having accidents

  • Discolored urine

  • Licking more often at the urinary opening

Your veterinarian can also recommend a monitoring plan if your dog has an underlying health problem that makes bladder or kidney infections more likely.

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Jennifer Coates, DVM


Jennifer Coates, DVM


Dr. Jennifer Coates is an accomplished veterinarian, writer, editor, and consultant with years of experience in the fields of veterinary...

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