There are several health conditions that can share symptoms with kidney problems, and can be mistaken for kidney disease. UTIs can cause symptoms such as frequent urination, painful urination, and blood in the urine, which can also occur in cats with kidney problems. Hyperthyroidism is a common condition in older cats that can cause weight loss, increased appetite, vomiting, and diarrhea. These symptoms can be mistaken for those of kidney disease. Diabetes can cause increased thirst, increased urination, and weight loss, which can be similar to the symptoms of kidney disease. Liver disease can cause symptoms such as vomiting, diarrhea, loss of appetite, and lethargy, which can be mistaken for those of kidney disease. Some types of cancer, such as lymphoma, can cause symptoms such as weight loss, vomiting, and diarrhea, which can be similar to the symptoms of kidney disease.