An evidence-aware guide to chronic kidney disease in dogs: IRIS staging, urine and blood-pressure tests, renal diets, treatment, monitoring and emergencies.

Seek urgent veterinary care for

Repeated vomiting, refusal to eat, severe lethargy or dehydration
Very little urine, no urine, painful urination or a sudden marked change in urine production
Collapse, severe weakness, tremors, seizures or altered consciousness
Breathlessness, very pale gums, black stool or uncontrolled bleeding
Possible ingestion of grapes, raisins, certain human medicines, antifreeze or another kidney toxin

What the kidneys do

Kidneys filter metabolic waste, regulate water and electrolytes, support acid–base balance, contribute to blood-pressure control and produce signals involved in red blood cell formation. Chronic kidney disease means functional kidney tissue has been lost or persistently damaged for long enough to be considered chronic.

Dogs can compensate for substantial kidney loss before obvious signs develop. Early CKD may be found during senior screening, urine testing or investigation of hypertension. Later, dogs may drink and urinate more, lose weight and muscle, become nauseated, develop poor appetite, bad breath, oral ulceration, anaemia or weakness.

Diagnosis: more than creatinine

Assessment	What it contributes	Important limitation
Creatinine	Common marker used for IRIS staging after stability is confirmed	Influenced by muscle mass, hydration and some laboratory factors
SDMA	May detect reduced filtration with less dependence on muscle mass	Must still be interpreted with trends, hydration and the full clinical picture
Urinalysis and urine specific gravity	Shows concentrating ability, sediment, glucose, blood and other clues	A dilute sample has many possible causes; collection method matters
Urine protein-to-creatinine ratio	Quantifies protein loss and supports IRIS substaging	Inflammation or bleeding in the urinary tract can affect interpretation
Blood pressure	Identifies hypertension risk and IRIS substage	Stress and technique can distort readings; repeated standardised measurements help
Imaging	Assesses size, architecture, stones, obstruction or congenital disease	Normal-looking kidneys do not exclude early functional disease

A single abnormal result may reflect dehydration, acute kidney injury, urinary obstruction, infection or another condition. IRIS recommends staging only after CKD is diagnosed and the patient is stable. When results conflict, repeat testing and a precautionary interpretation may be appropriate.

Understanding IRIS staging and substaging

IRIS stages CKD from 1 to 4 using stable creatinine and/or SDMA values, with clinical judgement. Stage 1 can include dogs with normal filtration markers but other persistent evidence of kidney abnormality. Higher stages indicate progressively reduced filtration and usually greater risk of uraemic signs.

Every stage should be further assessed for proteinuria and systemic blood pressure because these factors affect progression and may need specific treatment. Staging is not a prediction of an exact remaining lifespan. Dogs within the same stage can differ greatly in cause, rate of progression, appetite, muscle condition and response to treatment.

Questions at diagnosis

Is this chronic or acute?
What is the IRIS stage and substage?
Is there proteinuria or hypertension?
Is infection, obstruction or toxin exposure possible?
What result will be rechecked and when?

Track at home

Body weight and muscle condition
Appetite and food intake
Water and urine changes
Vomiting, nausea or bad breath
Energy, mobility and comfort
Medicine and fluid administration

Renal diets: what they are designed to do

Therapeutic renal diets are not simply “low protein.” They generally control phosphorus, use appropriate amounts of high-quality protein, provide adequate energy and modify sodium, fatty acids, buffering nutrients and other components according to the formulation. The aim is to reduce metabolic burden while preserving muscle and food intake.

Food transition must be practical. A dog that stops eating is at immediate risk of calorie and muscle loss. Gradual transition, warming food, offering approved textures and treating nausea can be more important than forcing a perfect diet. Homemade renal diets require formulation by a qualified veterinary nutrition professional and follow-up because calcium, phosphorus, potassium, amino acids and energy can easily become unbalanced.

Important: Do not add calcium, phosphate binders, potassium, bicarbonate, salt substitutes or herbal products without current laboratory results and veterinary instruction. The wrong supplement can create dangerous electrolyte or mineral abnormalities.

Treatment is matched to the dog’s problems

Management may include a renal therapeutic diet, control of phosphorus, treatment of proteinuria or hypertension, anti-nausea and appetite support, correction of dehydration and electrolyte or acid–base disturbance, treatment of infection when confirmed, and management of anaemia. Some dogs are taught subcutaneous fluid therapy, but fluids are not automatically appropriate for every stage or every heart condition.

Treatment goals change over time. Early management may focus on progression risk and blood pressure. Later management may prioritise appetite, nausea, hydration, comfort and maintaining enough energy intake. Medicine doses often require adjustment because kidney clearance changes.

A practical monitoring schedule

The interval depends on stage, stability and treatment. Newly diagnosed or changing patients are rechecked more frequently. Stable at-risk dogs may be monitored every few months and then at longer intervals, while advanced CKD may require much closer review.

At home	At the clinic	Why trends matter
Weekly body weight when practical	Creatinine, SDMA, urea, phosphorus and electrolytes	A trend is usually more informative than one isolated value
Food intake and vomiting log	Urinalysis, urine protein and culture when indicated	Protein loss and infection can alter treatment
Water and urine pattern	Standardised blood pressure	Hypertension may be silent until organ damage occurs
Energy, breathing and gum colour	Packed cell volume or haematocrit and complete blood count	Anaemia may emerge as disease progresses
Medicine and fluid record	Body and muscle condition assessment	Dogs can lose muscle even when scale weight seems stable

Acute kidney injury versus chronic kidney disease

Acute kidney injury develops over hours to days and may follow toxins, severe dehydration, infection, heatstroke, shock or obstruction. Some dogs recover partially or substantially with rapid treatment; others are left with CKD. A dog with known CKD can also suffer an acute-on-chronic crisis. Sudden vomiting, collapse, marked urine change or toxin exposure must not be dismissed as “just the kidney disease.”

Quality of life and advanced care

Families should discuss what comfort looks like for their dog: eating willingly, sleeping peacefully, interacting, moving without distress and maintaining hygiene. Advanced care may include more frequent hospital support, feeding assistance or referral options. Palliative decisions should be based on the dog’s experience, not only laboratory numbers.

Dogsvilla practical tip: Keep copies of the latest laboratory results, IRIS stage, medicine list and diet plan on your phone. This is valuable during travel or an emergency visit when the regular clinic is closed.