Can you train someone else up to cover urgent queries? Or write up some guidelines, if X happens, you need to do A and B, but if it's Y, then do C.
Depends on the nature of your job - but were you to leave, they would have to have some sort of handover or just deal with it, so what stops them in this case? Is it just that they know that you'll be back soon, so can deal with it, or lack of knowledge?
Pretty much all my job is documented - this is mostly so I can look things up if I forget, particularly with processes that aren't used so frequently, but it means everyone else benefits. Also, if I know I'm going to be on-leave, I make sure people involved with active projects have someone they can contact in my absence, and that contact person I will have done a handover with - "If they haven't returned this information by next Friday, please chase them. If they ask about that problem, use the document here to work through it and find out what's going on." It doesn't mean everything is picked up, even when specific people have been tasked with taking it on because some people are lazy wastes of space, and that is annoying, but at least I know it's not because I haven't given them the information they need to do whatever it is.
But there will be some jobs where that sort of handover isn't possible.