Chronic Kidney Disease

The kidneys filter waste products from the blood, regulate fluid balance and blood pressure, produce hormones, and activate vitamin D. Chronic kidney disease develops when the kidneys lose functional capacity over time - gradually, usually without obvious symptoms until 65–75% of function is lost.

This silent early phase is the key challenge: by the time obvious symptoms appear, significant damage has already occurred. Regular blood and urine screening in middle-aged and older dogs catches CKD at an earlier, more manageable stage.

Staging

CKD is classified by the International Renal Interest Society (IRIS) using blood creatinine, blood pressure, and urine protein levels:

• Stage 1: No azotaemia (creatinine normal), abnormalities detected by other means (urine, imaging)
• Stage 2: Mild azotaemia; few or no clinical signs
• Stage 3: Moderate azotaemia; signs begin to appear
• Stage 4: Severe azotaemia; often significant clinical signs

Earlier stage diagnosis allows earlier intervention.

What to monitor

At home:

• Water intake. Increased thirst and urination (PU/PD) are often the first signs of CKD. Log whether your dog is drinking noticeably more than usual. A rough way to quantify: measure the amount placed in the bowl and what's left after 24 hours.
• Urination. More frequent urination, larger volumes, or accidents in house-trained dogs.
• Appetite. Reduced appetite is common as kidney disease progresses (uraemia causes nausea).
• Body weight. Weigh weekly. Weight loss is a significant monitoring point.
• Vomiting. Nausea and vomiting increase as toxin levels rise.
• Energy and demeanour. Gradual reduction in energy, increased lethargy.

At the vet (schedule as directed):

• Blood tests: creatinine, SDMA (a more sensitive early marker), urea, phosphate, electrolytes
• Blood pressure measurement (hypertension is common and worsens kidney damage)
• Urine specific gravity and protein:creatinine ratio (UPC)
• IRIS staging review

Dietary management

Renal diets are specifically formulated to reduce the workload on damaged kidneys:

• Reduced phosphate - phosphate retention accelerates kidney damage; restriction slows progression
• Controlled high-quality protein - reduces nitrogen waste products
• Added omega-3 fatty acids - have some evidence for renoprotective effects
• Increased moisture - wet food or adding water to dry food supports hydration

Transitioning to a renal diet is most effective in Stages 2–3. In Stage 1, the benefit is less established. In Stage 4, palatable food intake takes priority over dietary restriction.

Log food intake carefully - a dog who refuses the renal diet is getting zero benefit from it. Work with your vet on palatability strategies.

Phosphate binders

If dietary restriction alone doesn't achieve target phosphate levels, oral phosphate binders (given with meals) are often added. Log administration alongside meals - timing with food is essential for efficacy.

Blood pressure management

Hypertension both results from and worsens CKD. If your vet identifies elevated blood pressure, medication (most commonly amlodipine) will be prescribed. Log doses and note any changes in demeanour.

When to contact your vet

Contact your vet promptly if:

• Vomiting, anorexia, or significant lethargy appear or worsen
• Weight loss is accelerating
• Your dog seems weak, disorientated, or has seizures (signs of advanced uraemia)
• Blood pressure is known to be poorly controlled

Schedule routine monitoring as directed - typically every 3–6 months in stable Stage 2–3 disease.

Frequently Asked Questions

Can CKD be reversed? Chronic kidney damage is not reversible. Management aims to slow progression, control symptoms, and maintain quality of life. The kidneys do have some compensatory capacity in early stages.

What is SDMA and why does my vet mention it? Symmetric dimethylarginine (SDMA) is a kidney biomarker that becomes elevated earlier than creatinine - it detects reduced kidney function when approximately 25% of capacity is lost, compared to 65–75% for creatinine. It allows earlier detection and intervention.

My dog's kidneys look normal on ultrasound - does that mean they're fine? Ultrasound assesses kidney structure, not function. Kidneys can appear structurally normal on ultrasound while losing significant functional capacity. Blood and urine tests are needed to assess function.

How long can a dog live with CKD? This varies enormously with stage at diagnosis, response to management, and breed. Well-managed Stage 2 dogs can live for years. Stage 4 dogs typically have months. Early detection and consistent management make a material difference.

Is raw feeding appropriate for a dog with CKD? Raw diets are generally not recommended for dogs with CKD. The high protein and phosphate content of most raw diets is exactly the opposite of what a renal diet aims for. Discuss any dietary considerations with your vet before making changes.