Old woman farting

An old woman walks into the doctor's office and says

"Doctor, I've got a little problem. I can't stop farting. It's not a bother as they are totally silent and don't smell at all. I've farted probably 20 times since I've walked in here and I bet you didn't even notice."

The doctor says "Hmm... Take these pills for a week and come back."

After a week has passed, the old woman returns and says "Doctor, I don't think that helped, I'm still farting all the time and they are still quiet, but now they smell like an open sewer!"

To which the doctor replies "Well, now that we've cleared up your sinuses, let's work on your hearing."