Q. I have a 7-year-old Maine Coon, Kasi, who was recently diagnosed with kidney disease. I'm in the process of finding a low-protein canned food. I recently offered her an over-the-counter kidney-treatment canned food and she likes it. Also, Kasi only drinks small amounts of water. What do you recommend for low-protein food, canned or dry? What causes kidney disease? I feel Kasi is too young to have kidney disease. I will do whatever it takes to bring her kidneys back to normal.

A. Kidney (renal) disease is a frustrating problem in animals. In some cases, an underlying cause can be found, but in others the cause remains a mystery. Your cat is too young to be showing signs of kidney disease, and it might be important to try and see if there is a treatable underlying cause for her problems.

Kidney infections (pyelonephritis) and stones in the kidneys (renal uroliths) are two potential causes of reversible kidney disease. Radiographs, ultrasound and a careful urinalysis (with a culture if indicated) can rule out these problems. Not all stones show up on radiographs, so that is why we often recommend an ultrasound. Cats with developmental disorders such as polycystic kidneys generally become symptomatic early in life. Unfortunately these problems are not reversible.

You need to know if your cat is losing protein in her urine (protein-losing glomerulonephropathy), as this condition is treated differently than other forms of kidney failure. Your veterinarian can perform a urine protein creatinine-ratio if a protein problem is detected by performing a routine urinalysis.

Prescription diets prove to be the best diets. Most manufacturers of veterinary diets make excellent foods. Putting your cat on a low-protein diet is probably not the best thing. Cats are obligate carnivores, so Kasi should eat a diet that provides an adequate protein content. Serving a diet with high but non-essential (low-quality) protein is detrimental to kidney patients, which means a high-quality, prescription diet is required.

Try to increase her water intake by feeding canned food or by flavoring her water with a few drops of clam juice or tuna juice.