Chronic kidney disease (CKD)

Symptoms an owner can spot at home

• Increased thirst and urination
• Gradual weight loss over months
• Decreased appetite, especially for protein
• Vomiting (more common in cats)
• Dull or unkempt coat
• Lethargy and reduced grooming

When to see a vet

• Sudden refusal to eat or drink for more than 24 hours
• Repeated vomiting in a senior pet
• Sudden collapse, disorientation, or seizure
• Marked increase in thirst combined with weight loss, book a senior wellness visit, do not wait

What it is

The kidneys filter waste, regulate fluid balance, maintain blood pressure, and produce hormones that drive red blood cell production. In chronic kidney disease, nephrons (the working units of the kidney) are progressively lost. Animals can compensate clinically until roughly two-thirds of nephrons are gone, which is why CKD is usually detected late.

The International Renal Interest Society (IRIS) stages CKD from 1 (earliest, often biochemically silent) to 4 (end-stage). Staging combines creatinine, SDMA (symmetric dimethylarginine), urine protein-to-creatinine ratio, and blood pressure. Knowing the stage drives every treatment decision.

How vets diagnose it

Routine senior bloodwork (typically annually from age 7, every 6 months from age 10) catches CKD earlier than waiting for symptoms. SDMA rises earlier in disease than creatinine and is now part of standard small-animal panels. A complete diagnostic workup also includes urinalysis with USG and UPC, blood pressure measurement, and imaging (ultrasound) to assess kidney architecture.

Management overview

This is editorial overview, not a treatment plan, your vet builds the plan based on IRIS stage and individual factors. Cornerstones include: a therapeutic renal-support diet (restricted phosphorus, moderated high-quality protein, omega-3 enriched, alkalinizing) which has level-1 evidence for extending survival; phosphate binders when serum phosphorus exceeds stage-specific targets; ACE inhibitors or telmisartan for proteinuria; subcutaneous fluid therapy at later stages; and management of secondary issues (anemia, hypertension, hypokalemia in cats, nausea).

Hydration is the lever owners control daily. Multiple water sources, pet water fountains, wet food, and (for cats) a low-stress litter setup that does not discourage drinking-adjacent behavior all matter.

Prognosis

IRIS stage at diagnosis is the strongest predictor. Cats diagnosed at stage 2 and managed with diet and ACE inhibitors commonly live 2-3 additional years; dogs progress faster on average. Quality-of-life conversations belong at every recheck, not only at the end.