Merck Manual

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Chronic Kidney Disease Stages

Chronic Kidney Disease Stages

Disease Stage

Physical Conditions



Stage I

Damage to the kidney is occurring, but waste chemicals in the blood are not abnormally elevated (azotemia not present).

No easily visible signs. Laboratory or other tests required but may not show abnormalities.

Identify and treat cause of kidney disease and any complications (such as high blood pressure or urinary tract infections). Ensure adequate water intake.

Stage II

Slowing of waste filtering to < 25% of normal. Buildup of waste chemicals and imbalance of water in urine.

Dog may be urinating more than previously, but other clinical signs of kidney disease are not yet present. Tests show increased amount of waste chemicals in blood.

Treat underlying cause and complications of the condition. A change of diet may be required (such as a low salt or other special diet). Ensure adequate water intake.

Stage III

Further loss of kidney filtering ability; blood and urine show further buildup of waste chemicals.

Excessive thirst and urination.

Support dog with kidney disease diet, monitor for infections, and treat underlying cause and complications of kidney disease.

Stage IV

Severe loss of kidney filtering ability. Toxic chemicals build up in blood and affect other organs in the body.

Vomiting, depression, loss of appetite, weight loss, dehydration, mouth sores, diarrhea. Young dogs may lose teeth. Bones can become soft and easily breakable.

Provide special diet. Treat underlying conditions. Provide comfort care. Administration of intravenous or subcutaneous fluids may be necessary. In severe cases, kidney dialysis or a kidney transplant might be possible.