My cat had one once several years ago! One day he was walking around the house whining, so my mom thought "Fluffy must have a bladder infection." She took him to the vet and explained the situation. The vet took a urine sample and confirmed that he did indeed have a bladder infection, so she gave him some medication. When I came home from school I found him under my bed. He wasn't acting like himself, so I asked my mom what was wrong, and she told me. For the next several mornings, both my parents had to go down into the basement to give him his medicine, one to hold him in a wrapped-up towel and the other to hold his mouth open and use the dropper to administer the medication. You could hear the meowing from the bedrooms on the second floor of the house!