Kidney disease affects an estimated 5.8% of dogs, according to a review of medical histories conducted at Michigan State University. The earliest signs are increased water consumption and increased urination. Symptoms remain subtle until more than 65% of kidney function is lost. Early detection, dietary phosphorus restriction, and fluid management are the primary tools for slowing disease progression.
For related reading, see Why Is My Dog Panting So Much? 8 Causes of Excessive Panting in Dogs.
What Are the First Signs of Kidney Disease in Dogs?
The first signs of kidney disease in dogs are increased water drinking and increased urination, followed by lethargy, reduced appetite, and gradual weight loss.
When the kidneys are not working properly, waste products build up in the blood, causing detrimental effects across multiple body systems.
In early kidney disease, the kidneys can no longer concentrate urine efficiently. They begin losing more water into the urine than they should. To compensate for that fluid loss, the dog drinks more. This phase is called compensated kidney disease. After approximately two-thirds of kidney tissue fails, waste accumulates in the bloodstream rapidly and severe disease appears to begin suddenly.
Kidney disease is most common in older dogs. For most small breeds, early signs appear at 10 to 14 years of age. Large breeds can develop kidney disease as early as 7 years. 15% of dogs aged 10 and older show structural and functional changes to the kidneys.
Why Is My Dog Drinking a Lot of Water?
A dog drinking a lot of water is often the first observable sign of kidney disease, but it can also indicate diabetes, liver disease, or Cushing's disease. A veterinary exam with bloodwork and urinalysis is required to identify the cause.
Monitor water intake by measuring what goes into the bowl each day. Any consistent increase in daily water consumption, especially combined with more frequent urination, in a dog aged 7 or older, warrants a vet visit within a few days. Dogs diagnosed with kidney disease at the compensated stage have more management options than those identified in advanced stages.
What Are the Symptoms of Kidney Disease in Dogs by Stage?
Kidney disease in dogs has 4 IRIS stages, rated by the International Renal Interest Society (IRIS) using creatinine, SDMA, and urine specific gravity values. At diagnosis, 78.6% of dogs are at IRIS Stage I or II, and 21.5% are at Stage III or IV, according to a study published in PMC by the National Institutes of Health.
| IRIS Stage | Kidney Function | Primary Symptoms |
|---|---|---|
| Stage 1 | Minimal loss | Few visible signs; SDMA may be elevated |
| Stage 2 | Moderate loss | Increased drinking, increased urination, lethargy |
| Stage 3 | Significant loss | Weight loss, appetite loss, vomiting, bad breath |
| Stage 4 | Severe loss | Uremia, collapse, mouth ulcers, pale gums |
Advanced stage symptoms include loss of appetite, weight loss, depression, vomiting, diarrhea, halitosis with an ammonia-like odor, mouth ulcers, unkempt coat, pale mucous membranes, and muscle weakness. A veterinarian examining a dog in advanced stages may also detect high blood pressure, a heart murmur, and small or shrunken kidneys.
The 6 key blood and urine values used to diagnose and stage kidney disease are:
- Blood urea nitrogen (BUN): elevated values indicate kidneys are not filtering waste
- Creatinine: measures kidney filtration efficiency
- SDMA: the earliest detection biomarker for kidney disease
- Urine specific gravity: lower values indicate more diluted urine and reduced concentrating ability
- Phosphorus: elevated levels worsen prognosis as disease advances
- Red blood cell count: low counts indicate anemia secondary to kidney disease
What Are the Signs of Anemia in Dogs with Kidney Disease?
Anemia develops in dogs with advanced chronic kidney disease because the kidneys can no longer produce adequate amounts of erythropoietin, the hormone that stimulates red blood cell production in the bone marrow.
As the kidneys lose function, erythropoietin production drops. The bone marrow is no longer able to replace lost red blood cells at a normal rate, producing non-regenerative anemia.
Red blood cells transport oxygen from the lungs to all body tissues. When red blood cell numbers fall, tissues receive less oxygen.
The 5 primary signs of anemia in dogs with kidney disease are:
- Pale or white gums (normal gums are pink and moist)
- Lethargy and reduced activity
- Exercise intolerance, including tiring faster than usual on walks
- Decreased appetite
- Weakness and, in later stages, labored breathing
Anemia is diagnosed via a complete blood count (CBC) or packed cell volume (PCV) test. Treatment includes darbepoetin, a hormone that replaces erythropoietin and stimulates red blood cell production. Blood transfusions are used in acute cases.
What Is Low Phosphorus Dog Food?
Low phosphorus dog food is a therapeutic diet that restricts dietary phosphorus to slow the progression of chronic kidney disease. Limiting dietary phosphorus in dogs with CKD delays disease progression, according to VCA Animal Hospitals. Phosphorus is directly linked to protein content in food. Reducing protein reduces phosphorus.
Phosphorus restriction begins at IRIS Stage 2. At Stage 2, a diet labeled for early kidney disease applies reduced phosphorus and moderately reduced protein. At Stages 3 and 4, more restricted levels of both nutrients are required.
Commercial renal diets range from 0.48 to 1.0 g/Mcal of phosphorus for dogs, according to a continuing education review published on dvm360. The goal for dogs with early kidney disease is to reduce phosphorus to approximately 100 mg per 100 kcals across the total diet.
Wet food is preferred over dry kibble in kidney disease. Wet food contains 65 to 75% moisture. Dry food contains only 8 to 10%. Feeding kibble to a dog with kidney disease can contribute to dehydration and worsens the kidneys' workload.
What Are Low Phosphorus Foods for Dogs?
5 low phosphorus whole foods are safe for dogs with kidney disease when used alongside a veterinary-recommended renal diet.
These are:
- Egg whites: low in phosphorus and gentle on the kidneys; egg yolks contain more phosphorus and are used in smaller amounts
- White rice: low in both phosphorus and potassium; a good base carbohydrate for kidney diets
- Pasta and pearled barley: low phosphorus cooked carbohydrates suitable as dietary base ingredients
- Potatoes and sweet potatoes: provide B vitamins and energy with moderate phosphorus levels
- Fatty meats (in controlled amounts): lower in phosphorus than lean cuts; used to add calories and palatability
Omega-3 fatty acids from fish oil reduce kidney inflammation and support immune function. Adding fish oil to a renal diet provides anti-inflammatory benefit alongside palatability improvement. Low sodium meat broth, applesauce, and a small amount of honey are also used as palatability enhancers for dogs that refuse renal food.
What Foods Should Dogs with Kidney Disease Avoid?
Dogs with kidney disease avoid 5 food categories: high-protein foods, high-sodium foods, foods high in phosphorus, dry kibble, and high-phosphorus treats.
Avoid these foods:
- Organ meats, especially liver: very high in phosphorus
- Cheese and deli meats: high in sodium and phosphorus
- Bread products: high in sodium
- Dry kibble: dehydrating; worsens kidney stress
- Tomatoes: excluded due to acid and potassium content
Meats and foods high in protein, phosphorus, and sodium have the potential to negate the benefits of the renal diet and make the patient feel worse in the short term, according to a dvm360 veterinary nutrition review.
Why Is My Dog Not Drinking Water?
A dog with kidney disease may stop drinking water due to nausea, mouth ulcers, uremia, or general loss of appetite caused by toxin buildup in the bloodstream.
The buildup of toxins, electrolyte imbalances, dehydration, and anemia all reduce appetite and thirst drive in dogs with kidney disease. Mouth and stomach ulcers add further aversion to eating and drinking. This creates a compounding problem: the dog needs more fluid intake to support kidney function but feels too unwell to drink.
How Do I Get My Dog to Drink More Water?
4 evidence-based methods help increase water intake in dogs with kidney disease.
These are:
- Change the water several times daily and clean the bowl daily. Fresh, clean water is more appealing and reduces bacterial build-up that can deter drinking.
- Switch to canned or wet renal food. The moisture content of wet food directly contributes to daily fluid intake in a way kibble does not.
- Add water or low sodium broth to food. This increases total daily fluid intake without relying on the dog to drink from the bowl.
- Use subcutaneous (SQ) fluids at home. Vets can train owners to administer fluids under the skin, maintaining hydration and flushing accumulated toxins. In advanced stages, intravenous (IV) fluids given at the clinic can temporarily improve kidney function through a process called diuresis.
When Should a Dog with Kidney Disease See a Vet?
Schedule a vet appointment within 1 to 2 days if a dog shows any combination of increased thirst, weight loss, lethargy, and reduced appetite. Seek emergency care if the dog shows vomiting that does not stop, collapse, refusal to eat or drink for over 24 hours, pale or blue gums, or ammonia-like breath.
Dogs 7 years and older benefit from annual blood panels and urinalysis even without symptoms. SDMA is detectable before creatinine rises, making it the most useful early detection marker. Annual screening gives the best chance of identifying kidney disease at IRIS Stage 1 or 2, when the most management options are available.
Helen L. Corlew runs a team of Samoyeds, Alaskan malamutes and Alaskan huskies. I am a Tellington TTouch practitioner and use this mode of work with training and living with my dogs.
Helen Corlew founded Prairie Isle Dog Trekking in Petersburg, North Dakota in 2010, and has spent the fifteen years since doing something most people only read about: teaching real dog sledding on real prairie terrain, at the edge of a landscape that doesn’t apologize for being difficult.
She is not a weekend enthusiast. She harnesses working dogs in January cold, trains handlers who have never touched a sled, and has built one of the only hands-on mushing education programs on the Northern Great Plains — from a single address on Highway 2, with no marketing budget and no shortcuts.
Her writing on Prairie Isle Dog Trekking reflects the same philosophy. Whether she is covering trail safety across the Rockies, breed behavior in extreme conditions, or what it actually takes to trek with a dog in the Alps, Helen writes from the position of someone who has done the work before writing the sentence.
She lives and runs dogs in Nelson County, North Dakota.
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