This is sometihing I have wondered about. If you think it's a possibility, let me know. I had mono for the first time a few years ago. As an adult, I couldn't really take off work and rest for months like some kids do when they get it at a young age. months later, I had some tests run and my spleen was enlarged, so the doctors suspected it was still the mono causing it. For a while, before IC, I have felt chronic fatigue and wondered if mono had anything to do with it.