Kidney Disease In Cats And Dogs
The kidneys filter waste products out of the blood into urine and have an important role in concentrating the urine. When they are not working properly, these waste products start to build-up in the blood, making the animal feel unwell. Common symptoms of renal disease include:
- Increased thirst and urination
- Decreased appetite
- Weight loss
- Dehydration
- Lethargy
- Bad breath
- Vomiting
Urinalysis
Animals with renal disease have very dilute urine - elevation of urea/creatinine with concentrated urine is usually caused by dehydration not kidney disease. Measuring the protein:creatinine ratio in urine gives us a measure of how "leaky" the kidneys are - too much protein in the urine suggests more advanced disease.
SDMA
A specific blood test. SDMA levels rise in early renal disease, so persistent elevation can help confirm and stage diagnosis.
Blood pressure
Animals with renal disease often have or develop high blood pressure (hypertension), this should be checked at diagnosis and monitored regularly if possible.
Imaging
Ultrasound can be used to assess the structure of the kidneys, and looks for cysts and tumours. X-ray may be used if kidney stones are suspected, though these are less common in animals than in people.
How is Kidney Disease treated?
Kidney disease can be managed, but not cured, as the damage is irreversible. Treatment is focused on slowing further deterioration and maintaining quality of life, and includes:
Diet
A prescription renal diet contains high calories with low protein, controlled Phosphorus, reduced Sodium and increased Potassium, vitamins and antioxidants. It should be introduced over 1-3 weeks, and ideally be the sole food if this is tolerated.
Hydration
Avoiding dehydration is extremely important. Water intake can be encouraged with wet food, more frequent meals, and the use of water fountains. Some patients who are very dehydrated may need administration of fluids via a drip for 24-72 hours, requiring a hospital stay.
Medication
There is no medication to specifically improve kidney function, however, both high blood pressure and excessive protein in the urine can be managed medically; sometimes one drug will treat both problems.
Animals with kidney disease often feel nauseous, so medication to reduce stomach acid or prevent nausea may be prescribed. In some cases, it may be appropriate to use appetite stimulants, though these are not usually a long-term solution.
What is the outlook for cats and dogs with Kidney Disease?
CKD is a terminal condition and, ultimately, affected animals will deteriorate. For pets who are diagnosed on a routine blood test, or who are still quite well, the condition can often be managed successfully for months or even years. Pets who present very unwell have a much more guarded prognosis, as there is often progressed damage to the kidneys and it can be hard to get significant improvement, even with aggressive treatment.
The International Renal Interest Society (IRIS) have created a grading system, referred to as IRIS staging. This uses parameters such as creatinine level, SDMA level and blood pressure to determine what stage of CKD a cat or dog is in. This helps with both treatment plans and prognosis. Your vet will be able to explain in more detail, but further information can be found on the IRIS website.
