Drinking more than usual

I have a twelve year old male Norwegian Forest cat. I have recently noticed that is drinking more than usual, he appears to be loosing weight and has begun to urinate in inappropriate places. Otherwise he seems fine in himself, is playful and has a good appetite. I am worried that it might be renal failure.

Hello!  I'm afraid that this is indeed a possibility.  There are other possibilities, too: diabetes, liver disease, possibly certain bladder infections and (I'm afraid) cancer can be common ones.   None of these things are quick fixes but some are treatable and early treatment, especially with diabetes, is extremely important.  Please contact your vets immediately in case they want to see you as an emergency.

You are right to worry about kidney disease, but again - it is progressive and rapid treatment can help a lot.  Please do seek out vet advice as your next step - a problem faced becomes quantifiable; once you know what is happening, you will know whether and how you can help.   A urine sample may help your vets to know where to start looking, so it might be worth throwing the cat litter away and putting an empty tray down while you make the phone call.  Never withold water, even if it seems to go straight through.   Best of luck and please do let us know how you get on.

I haven't mentioned hyperthyroidism, which can also cause of excessive thirst and weight loss.  Cats with hyperthyroidism have a very fast metabolic rate and burn energy very quickly, so often they become thin and restless.  Cats can live with hyperthyroidism for a long time, but again, rapid diagnosis may be a good idea.