Kidney disease in cats - the silent killer

1 in 3 cats will develop kidney disease during their lifetime. The signs are subtle, and the disease can progress to kidney failure before it's recognized. Thankfully, there are screening tests available to monitor your cat's kidney health, so we can intervene and slow down the disease before your cat ever feels ill.

​The kidneys play a key role in filtering the blood and removing waste products. As their function decreases, those waste products build up in the blood and cause illness. The kidneys are also important in balancing electrolytes. Kidney disease allows important salts and proteins to leak through and be lost in the urine.

Signs of kidney disease:

• Weight loss
• Decreased appetite
• Vomiting
• Increased thirst
• Increased urine production
• Decreased energy or activity

How to diagnose kidney disease:
Cats 7 years old and older should have screening for kidney disease done every year, and twice per year after they're 10 years old. This gives us the best chance of catching kidney disease in its early stages, where simple diet change can have a huge impact. If you notice any of the signs of kidney disease in your cat, your veterinarian can run a few simple tests to assess kidney function. We start with a complete physical exam, including palpating the kidneys. Cats with chronic kidney disease often have small firm kidneys. We then run blood and urine tests and check blood pressure.

Blood tests:
The earliest blood marker of kidney disease is SDMA. It can detect as little as 1/4 kidney function loss, well before there are any outside signs of illness.
Creatinine and BUN increase when 3/4 of kidney function is lost.  The cats usually feel ill as these increase.

Urine tests:
Isosthenuria, where the concentration of the urine is the same as the blood plasma, occurs once approximately 2/3 of kidney function is lost. 
Proteinuria, where the kidneys leak protein, requires special additional treatment.
We also evaluate for red and white blood cells, bacteria, abnormal urinary tract cells or casts, and crystals. These can indicate infection or ongoing kidney injury.

Blood pressure:
Cats with chronic kidney disease often develop hypertension. This then causes more kidney injury as the high blood pressure damages the remaining functioning kidney.  We can interrupt this vicious cycle with appropriate medication.

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Treating Kidney Disease:
While there's no cure, cats with chronic kidney disease (CKD) can live for years with good quality of life if their disease is managed. Frequent monitoring is the key to success so treatments can be adjusted.

• Look for an underlying cause - infections, toxins, stones, cancer, and other diseases can all have an impact on the kidneys. Sometimes, treating that infection or supporting through the toxin exposure can reverse the kidney disease.
• Adjust diet - kidney-supporting food, like Hill's K/D or Purina NF, have been shown to greatly prolong the lives of cats with kidney disease and decrease the number of hospitalizations. Canned food helps provide additional fluid support.
• Keep fresh water readily available - some cats prefer moving water, like faucets or fountains. Other cats enjoy ice cubes in their water. Try to entice your cat to drink, since it is easy for a cat with kidney disease to become dehydrated.
• Supplements like Azodyl and Epakitin can support kidney function. They come as powders and are easy to add to food.
• Manage blood pressure - medication is used to manage hypertension if necessary. This can be compounded into a cream applied to the inside of the ear or a flavored liquid if your cat doesn't take pills easily. The most common medication is amlodipine.
• Treat urine protein loss - benazapril and enalapril are commonly used to decrease urine protein loss if needed. These can also be compounded to make them easy to give to your cat.
• Manage electrolytes - tasty potassium tablets and gels are available when your cat's potassium level falls, and phosphorus binders can be given with meals when phosphorus levels climb too high.
• Give additional fluids - fluids can be given under the skin to keep your cat better hydrated. It is amazing how much better they feel once they have their fluids, and most cats will let you do this comfortably at home. We can teach you how when the time comes.
• Treat anemia - over time, cats with chronic kidney disease usually develop anemia. This contributes to their feelings of weakness. A bone marrow stimulant like darbepoeitin and iron supplement can be used carefully at this point. We can weigh the pro's and con's when the time comes.

We tailor treatment of kidney disease to the individual cat. This is a disease that we manage over the course of years, and quality of life is the most important. Some cats will permit every intervention while others are happier with a less-is-more approach. By being aware of changes to your cat's routine, you can help us catch this early and find the best strategy for treatment.

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