Next to noticing that your cat is drinking and urinating more often, the other big tip-off that your cat may have kidney disease is a sudden loss of weight.
The weight loss is often because one of the symptoms of kidney failure is a loss of appetite and possibly nausea. Unfortunately, you may not notice that your cat is eating less until he or she has dropped several pounds. Weight loss is considered to be a serious problem when it exceeds 10 percent of your cat's normal body weight.
You may eventually notice the weight loss as well as an overall boniness to your cat that you didn't see before. Their spines and haunches may stick out. It could be due to the nausea and loss of appetite. Or the fact that your cat is drinking and urinating more, and therefore may be losing protein and electrolytes.
However, weight loss is associated with other feline diseases such as diabetes, thyroid disease, and inflammatory bowel disease, too. So it's important to get your cat tested by your vet to determine the cause of the sudden weight loss.
Presuming that your cat is diagnosed with kidney disease, you'll start a new special diet for her and start doing everything you can to maintain her weight, including low-protein foods, hydration, treats, and more.
See also:
Appetite Boosters for Cats with Kidney Disease
Nutritional Supplements for Cats with Kidney Disease