Here's a question about a not-uncommon problem.
How do you get a cat to eat when she can't smell her food?
We have a sick kitty with a stuffy nose so I got three cans of the smelliest Fancy Feast I could find and mixed it together with some tuna juice. My husband could smell it from across the room. The cat though, doesn't seem to be interpreting it as food when it's right under her nose.
I've also got her segregated away from our other two cats in the bathroom. I've got a vaporizer running in there for her to help break up her congestion. Is there anything else I can do to help her feel better and get her to eat?
Cats are very particular about being able to sense their food. When a cat can't smell the food, they won't eat it. This can make sinus or upper-respiratory infections pretty serious even if the infection itself isn't bad. First, the reason for the infection should be addressed. Whether it is viral or bacterial your vet should be able to help find the right medication.
Another consideration is whether the congestion is caused by a tumor or foreign object. Masses or something inhaled can cause a blockage in the airways that can be more serious than simply having difficulty smelling. Again, your vet can help determine if this is the problem and what could be done.
Let's assume that we have the problem properly diagnosed and under treatment, but the kitty can't smell or eat. The first thing is to use something with a very strong odor, such as you're doing. If that doesn't work, try to warm it up in the microwave for a few seconds. Be careful not to overheat it or it could burn the mouth. Warming it makes the odors stronger which will hopefully entice kitty to eat.
A few days of not eating isn't a serious problem, but not eating for longer can cause serious problems, including a disease called fatty liver syndrome (hepatic lipidosis) which can be life-threatening. Your vet may be able to give vitamin or other injections to stimulate the appetite. Intravenous valium stimulates the appetite in cats for reasons that we don't understand, but this isn't something you can do at home. If the appetite doesn't pick up soon, be sure to consult your vet.