Signs of Kidney Disease in Dogs

Kidney disease is a common condition in senior dogs, but it often sneaks up on pet owners. Pet parents may mistake the early signs of kidney disease for normal aging, or symptoms may be so vague that pet parents don’t realize anything is wrong. Early detection of canine kidney disease symptoms allows for earlier intervention, which generally translates to better outcomes for pets.

Here, we’ll explain the common signs of kidney disease in dogs, including early symptoms. We’ll also discuss how to tell if your dog has kidney disease and what to do if you’re concerned.

What Is Kidney Disease in Dogs?

The kidneys serve several important functions for your dog’s overall health.

1. Filtering toxins: The kidneys remove waste products from the blood and excrete them in the urine. A tube called a ureter connects each kidney to your dog’s bladder.
2. Regulating mineral levels: The kidneys help maintain appropriate levels of minerals like potassium and sodium in the blood.
3. Managing blood pressure: The kidneys regulate blood volume by controlling the excretion of salt and water in the urine. They also release an enzyme called renin that affects blood vessel constriction. Both functions affect blood pressure.
4. Maintaining hydration: The kidneys help to conserve water as they filter toxins out of the blood. Some of the liquid is excreted as urine, but much is retained in the circulatory system.
5. Stimulating red blood cell generation: The kidneys secrete a hormone called erythropoietin, which causes the body to make more red blood cells.

When a dog has kidney disease, the kidneys start to lose some of their function and can no longer efficiently filter waste products from the blood. Toxins begin to build up in the blood rather than being excreted in the urine.

Kidney disease can be acute or chronic. Acute kidney disease comes on suddenly, usually as a complication of another condition, while chronic kidney disease in dogs generally develops slowly.

Because chronic kidney disease develops slowly and is usually a condition of senior dogs, early signs of kidney disease in dogs are easy to miss. You may assume some of the early symptoms are due to your dog’s normal aging.

Acute vs. Chronic Kidney Disease: Understanding the Difference

As mentioned, acute kidney disease usually occurs secondary to another condition. Acute kidney failure symptoms in dogs usually come on suddenly.

Potential causes of acute kidney injury in dogs include:

• Toxin ingestion (e.g., antifreeze, heavy metals, rodenticides, grapes or raisins, toxic plants)
• Bacterial kidney infection (pyelonephritis)
• Certain systemic infections, such as leptospirosis or Lyme disease
• Medication reactions or overdoses
• Kidney or bladder stones blocking urine output
• Tumors of the urinary tract blocking urine output
• Shock
• Heatstroke

Chronic Kidney Disease (CKD) develops slowly, and so do its symptoms. This condition is irreversible, but progression can be slowed with appropriate, early intervention. CKD often occurs without an inciting cause, though acute kidney disease may lead to CKD. Breed and age can play a role in the development of kidney disease.

Both acute kidney injury and chronic kidney disease require veterinary attention. If intervention is sought early, acute kidney injury is sometimes reversible. For chronic kidney disease, intervention is important for ruling out other conditions, like diabetes, and can slow the progression of the disease.

Risk Factors for Kidney Disease in Dogs

The following are risk factors for developing chronic kidney disease:

• Senior age, though some familial forms can develop earlier
• Being a breed with genetic predispositions, such as Shar Pei, Bull Terriers, English Cocker Spaniels, Cavalier King Charles Spaniels, Boxers, and West Highland White Terriers
• Other health disorders, including heart disease, high blood calcium, dental disease, and diabetes
• Long-term use of certain medications, including NSAIDs, various classes of antibiotics, and chemotherapeutics
• High blood pressure, which can feedback with CKD to worsen dog kidney disease symptoms
• Previous acute kidney injury

Common Signs of Kidney Disease in Dogs

Luckily, your dog has two kidneys, and one can pick up the slack if the other is failing. For clinical signs to be seen, your dog must lose 2/3 of their kidney function. On the negative side, this means significant damage has already been done before your dog starts to show signs.

Signs of kidney disease in dogs include:

• Increased thirst
• Frequent urination or accidents
• Dilute urine
• Decreased appetite
• Weight loss
• Vomiting or diarrhea
• Bad breath (uremic odor)
• Lethargy and weakness
• Poor coat quality
• Dehydration
• Ulcers in the mouth

Early Signs of Kidney Disease in Dogs

Keep in mind that once signs develop, significant kidney injury has already occurred. Still, the earlier you notice signs, the earlier you can intervene to slow progression.

Early signs of kidney disease in dogs include:

• Slight changes in drinking habits or having to refill the water bowl more often
• Mild appetite decrease
• Increased nighttime urination or accidents

When to Call the Veterinarian

If you are concerned about kidney disease, you should contact your veterinarian. In addition to the clinical signs we’ve listed above, additional signs that indicate you may need to contact your veterinarian include:

• Blood in urine
• Straining to urinate
• Signs of dehydration (prolonged skin tent, sunken eyes, dry gums)
• Pale gums

If your dog collapses or is unable to produce urine, you need to seek emergency attention.

You should also contact your veterinarian and/or poison control if your dog has consumed any toxins or human medications. Speak with your veterinarian if your pet receives an overdose of medication, as well.

How Kidney Disease in Dogs Is Diagnosed

Your veterinarian will perform a physical exam on your dog. During this physical exam, they’ll palpate (examine by touch) your dog’s kidneys for any obvious abnormalities or pain. They will also check in the mouth for ulcers and uremic breath.

The main way to diagnosis CKD is through bloodwork and urinalysis. Other tests may be recommended, including:

• Blood pressure measurement: Dogs with CKD often have hypertension. Hypertension can damage the kidneys, further worsening the CKD.
• Urine protein to creatinine ratio (UPC): This test helps determine if the protein detected in the urine is abnormally high.
• Imaging, such as abdominal x-rays or ultrasound: The veterinarian may check to see if the kidneys are enlarged, cystic, blocked, or if there is a tumor present.

Routine senior wellness screening is recommended to detect CKD. The typical recommendation is to have bloodwork at least every 6 months. SDMA may elevate prior to creatinine, allowing for earlier recognition of CKD. Regular screening also helps catch cases in which signs have been subtle or missed.

If an acute kidney injury is suspected, specific testing for conditions like leptospirosis or Lyme disease could be recommended in addition to the tests listed above.

Stages of Kidney Disease in Dogs

Chronic kidney disease in dogs is staged using the International Renal Interest Society (IRIS) guidelines, which utilize blood creatinine and SDMA levels to stage CKD. There are four stages of kidney disease in dogs:

Stage 1: At this stage, the dog is not azotemic. They have a normal blood creatinine and normal or mildly elevated SDMA levels. However, they’ll have a different abnormality present, such as:

• Persistently increased SDMA
• Creatinine and/or SDMA consistently increasing within the reference interval
• Enlarged or abnormal kidneys detected on imaging (usually X-rays or ultrasound)
• Protein in the urine

The dog may show subtle and mild signs, like increased thirst and urination.

Stage 2: At this stage, the dog has mild azotemia. SDMA is elevated, and creatinine is normal or mildly elevated. Signs are usually still relatively mild and include increased thirst and urination.

Stage 3: The dog has moderate azotemia, with elevated creatinine and SDMA. Signs may be more severe. The dog may be nauseous, causing vomiting and reduced appetite. Weight loss may be noted.

Stage 4: The dog is severely azotemic. Creatinine and SDMA are severely elevated. The dog may have significant weight loss, be lethargic, and have severe vomiting and diarrhea. The dog might also be anemic because of poor erythropoietin production.

Dog Kidney Disease Treatment Options

Dog kidney disease treatment is guided by how the dog is doing clinically and what stage they’re in.

For dogs who are severely ill, such as those with acute kidney injury, intravenous fluid therapy is the most important treatment. Fluids are given at a high rate to “flush” toxins from the system. Your dog will need to stay in the hospital, potentially for several days. Any known underlying conditions, such as leptospirosis or Lyme disease, must also be treated.

Treatments for CKD in dogs include:

• Therapeutic renal diet: These prescription diets restrict the levels of phosphorus, protein, and sodium. They often have higher levels of omega-3 fatty acids and potassium. The goal is to reduce the presence of toxins in the blood and slow disease progression.
• Constant access to fresh water: Dogs will be producing more urine, so they can become dehydrated more easily. Constant access to fresh water prevents dehydration.
• Anti-nausea medications: Medications like maropitant citrate (Cerenia) or ondansetron may be prescribed to reduce the nausea that occurs as a result of toxin build up.
• Blood pressure medications: Medications like benazepril (an ACE inhibitor) and/or amlodipine (a calcium channel blocker) may be recommended if your dog has high blood pressure (hypertension).
• Phosphate binders: If phosphate levels remain elevated on a renal diet, the addition of phosphate binders, such as aluminum hydroxide, is recommended.
• Subcutaneous fluids: In dogs who are dehydrated despite access to fresh water, routine administration of fluids under the skin may be necessary. Your veterinarian may show you how to administer these fluids at home.
• Darbepoetin: This injection is given under the skin, usually weekly at first, to stimulate red blood cell production. Dosing interval can be extended to every 2 to 3 weeks once target levels are reached.

At any stage, drugs that could potentially harm the kidneys, such as NSAIDs, should be used with caution.

Keep in mind that your dog may require additional treatments not listed here if other abnormalities or concurrent diseases are present.

At lower stages, follow-ups for monitoring may be recommended every 6 months. As the disease progresses, rechecks may be every 3 months. If your pet needs more advanced treatments, like darbepoetin, or their blood pressure is difficult to control, rechecks may be even more frequent.

Can Kidney Disease Be Prevented?

Not all cases of kidney disease are preventable, but you can take steps to reduce your pet’s risk:

• Get regular veterinary exams to detect abnormalities early
• Keep toxic products and medications out of your dog’s reach
• Maintain your dog’s dental health
• Provide constant access to fresh water
• Vaccinate against leptospirosis
• Use parasite preventives to keep your pet safe from tick-borne diseases

Remember not to assume changes to your senior dog’s behavior are caused by normal aging. It’s wise to get any changes checked out by a veterinarian.

Chronic kidney disease may not be reversible, but its progression can be slowed if it’s caught early. Early intervention also increases the likelihood of survival for dogs with acute kidney injuries. To catch CKD early, make sure to request or approve routine lab work at your regular veterinary check-ups. If you notice any possible signs of kidney disease in your dog, contact your veterinarian promptly for testing and guidance.