Kidney Disease in Dogs: Causes, Symptoms and Treatment

Vet verified. Written by Corinne Homer, Copywriter. Reviewed by Dr. Linda Simon MVB MRCVS, Team Vet.

Kidney disease can be acute, developing over hours or days, or chronic, progressing over months or years. Both need veterinary diagnosis. Increased thirst and urination, nausea, reduced appetite, weight loss, low energy, bad breath, vomiting and dehydration can occur, but early chronic kidney disease may cause few obvious signs.

Call a veterinarian promptly if your dog's drinking, urination or appetite changes. Go to an emergency clinic for collapse, seizures, severe weakness, repeated vomiting, inability to keep water down, suspected toxin exposure, little or no urine, or a painful swollen abdomen. Do not wait for an online stage chart to decide whether a sick dog needs help.

What do the kidneys do?

The kidneys filter metabolic waste from the blood, regulate water and electrolytes, help control blood pressure, support red blood cell production and contribute to acid-base balance. They also concentrate urine when the body needs to conserve water. A dog can lose substantial kidney function before routine signs become easy to notice, which is why history, examination, bloodwork, urinalysis and repeat measurements matter.

Kidney disease is not the same as a single abnormal lab value. Dehydration, muscle mass, medication, urinary obstruction and other illnesses can affect results. A veterinarian interprets creatinine and SDMA alongside urine concentration, urine protein, blood pressure, imaging, clinical signs and changes over time.

What causes kidney disease in dogs?

Acute kidney injury

Acute kidney injury may follow exposure to toxins such as grapes, raisins, antifreeze or certain medications; severe dehydration or shock; infection; urinary obstruction; heat injury; or another critical illness. The damage may be partly reversible when the cause is identified and intensive treatment starts quickly. Never give a human pain reliever or another pet's prescription to a dog. If an exposure is possible, keep the package and contact a veterinarian or animal poison-control service immediately.

Chronic kidney disease

Chronic kidney disease, or CKD, is persistent loss of kidney structure or function. It may be associated with aging, inherited disease, previous kidney injury, chronic infection, immune-mediated disease, abnormal protein loss, high blood pressure, urinary tract problems or an unknown cause. Chronic disease usually cannot be cured, but an individualized plan can reduce complications, support quality of life and sometimes slow progression.

Signs and symptoms of kidney disease in dogs

• Drinking more and producing larger volumes of urine.
• Urinary accidents or needing to go outside more often.
• Reduced appetite, food aversion or nausea.
• Weight or muscle loss and declining body condition.
• Vomiting, diarrhea or constipation.
• Low energy, weakness or less interest in normal activities.
• Dehydration despite increased drinking.
• Unusual breath odor or sores in the mouth in advanced disease.
• Pale gums when anemia develops.
• Sudden blindness, disorientation or neurologic signs when severe hypertension causes target-organ damage.

These signs overlap with diabetes, liver disease, hormonal disorders, urinary infection, gastrointestinal disease and many other conditions. Measure what changes rather than trying to diagnose from one symptom. Note water intake, urine frequency, appetite, vomiting, stool, medication and body weight for the clinic.

How veterinarians diagnose kidney disease

The workup begins with history and physical examination. Blood tests may assess creatinine, blood urea nitrogen, SDMA, phosphorus, potassium, calcium, red blood cells and other markers. Urinalysis evaluates concentration, sediment and evidence of infection. A urine protein-to-creatinine ratio helps quantify protein loss, while urine culture may be needed when infection is suspected. Blood pressure is important because kidney disease and hypertension can worsen each other.

Ultrasound or radiographs can show kidney size, shape, stones, obstruction or structural changes. Some dogs need infectious disease testing or specialist assessment. One result rarely tells the whole story. Stable chronic disease is confirmed with persistent abnormalities and repeat testing, while a rapidly changing patient is managed as possible acute injury rather than assigned a chronic stage too early.

Acute versus chronic kidney disease

Acute injury often has a sudden history and changing laboratory values. Chronic disease may come with longer-term weight loss, small irregular kidneys, anemia or a history of increased thirst. A dog can also have acute injury on top of CKD. The distinction affects treatment and prognosis, so owners should not label every high creatinine result as end-stage failure.

IRIS stages of chronic kidney disease

The International Renal Interest Society, or IRIS, stages stable CKD from 1 to 4 using fasting blood creatinine and/or SDMA after diagnosis. Dogs are then substaged by urine protein and systolic blood pressure. The stage helps organize treatment and monitoring, but it does not predict an exact lifespan. Trends, appetite, hydration, complications, other diseases and response to care all influence the individual outlook.

Stage 1

Creatinine may still fall within a reference interval. Persistent SDMA elevation, reduced urine-concentrating ability, renal proteinuria or structural kidney abnormalities may support the diagnosis. The plan focuses on confirming persistence, finding treatable causes, avoiding kidney stressors, measuring blood pressure and protein loss, and monitoring trends.

Stage 2

Mild azotemia is present and some dogs still appear well. Others drink or urinate more. A veterinarian reviews hydration, calories, phosphorus, potassium, blood pressure and proteinuria. IRIS guidance commonly introduces a therapeutic renal diet at this stage when appropriate, with a gradual transition while appetite is still good.

Stage 3

Clinical signs and treatment needs become more variable. Nausea, reduced appetite, dehydration, anemia, high phosphorus, acid-base problems or hypertension may need targeted care. Monitoring intervals are usually shorter and the plan changes according to the dog's response.

Stage 4

Severe loss of kidney function carries a high risk of uremic illness and quality-of-life decline. Treatment prioritizes hydration, nausea control, nutrition, comfort and complications. Some referral centers offer advanced options for selected patients, but decisions should match prognosis, burden of care and the dog's daily experience.

Treatment for kidney disease in dogs

Treatment depends on whether injury is acute or chronic and on the cause, stage and complications. Acute cases may need hospitalization, intravenous fluids, careful urine-output monitoring, toxin-specific care, nausea control, electrolyte correction and treatment of infection or obstruction. Giving large amounts of fluid at home can be dangerous, especially when urine output is poor.

Chronic care may include a therapeutic renal diet, anti-nausea or appetite medication, phosphorus control, treatment of hypertension or proteinuria, correction of potassium or acid-base problems, anemia management and planned hydration support. Not every dog needs every item. Supplements and medications must be chosen around current labs and other disease.

What is a veterinary renal diet?

A therapeutic renal diet is formulated differently from ordinary maintenance food, commonly with controlled phosphorus and adjustments to protein quality, sodium, energy density and fatty acids. It is not simply a low-protein homemade diet. Restricting protein or minerals without professional formulation can create malnutrition, muscle loss or an unbalanced recipe. Use the food and transition schedule your veterinarian recommends, and report reduced intake quickly.

Finch & Barker does not currently sell a veterinary renal food. Neither Mushroom Chews nor Deluxe Pet Dental Spray treats kidney disease or replaces a prescribed diet, fluid plan or medication. Mushroom Chews are adult everyday wellness support only and should be used in a dog with kidney disease only if the treating veterinarian approves every ingredient.

At-home monitoring without unsafe restriction

1. Keep fresh water freely available unless a veterinarian gives a rare, specific instruction otherwise.
2. Measure food offered and food left so appetite change is visible.
3. Weigh the dog weekly on the same scale when practical.
4. Record vomiting, stool, urination, accidents and energy.
5. Give medication exactly as prescribed and never double a missed dose without advice.
6. Attend blood, urine and blood-pressure rechecks on schedule.
7. Call early when eating declines because prolonged poor intake can make the plan harder to stabilize.

Foods, treats and supplements to discuss first

Do not add high-phosphorus treats, salt-heavy foods, raw diets, bone meal, mineral powders, herbal detoxes or concentrated supplements to a renal plan without approval. Grapes and raisins are toxic to dogs and require urgent action after any suspected exposure. Check flavored medications, dental products and pill pockets because extras can affect calories, sodium, phosphorus or appetite.

Palatability matters, but repeatedly changing foods can create aversion or digestive upset. Ask the clinic for an ordered plan: warming food, changing texture, adding approved water, using a prescribed appetite or nausea medicine, or selecting another therapeutic formula. Never force-feed a nauseated dog.

Planning rechecks and quality of life

Recheck frequency depends on the stage, blood pressure, urine protein, medications and whether results are changing. Keep copies of laboratory trends rather than focusing on one number. At home, track comfortable sleep, interest in family, appetite, mobility, nausea, hydration and favorite activities. A good plan responds to both laboratory complications and the dog's lived experience.

Ask the clinic what change should trigger an earlier visit and which symptoms warrant an emergency hospital. If giving medication becomes stressful or appetite support is failing, say so promptly. Adjusting the form, schedule or goal can reduce treatment burden without abandoning care. End-of-life discussions are appropriate when suffering cannot be controlled; they are individualized decisions, not determined by the IRIS number alone.

When kidney disease is an emergency

Seek emergency care for suspected toxin exposure, collapse, seizures, severe weakness, repeated vomiting, inability to keep water down, a sudden major decrease in urine, straining without producing urine, blood in urine with illness, severe dehydration, difficulty breathing or sudden blindness. Bring medication and supplement lists plus any toxin packaging. Do not induce vomiting unless a veterinary professional directs it.

US veterinary references and related reading

Use the current IRIS kidney guidelines for CKD staging, substaging and treatment principles. IRIS emphasizes that staging applies after CKD diagnosis in a stable patient and that care is individualized. Continue with our guide to food for dogs with kidney disease.