If your spleen is so big that it is in danger of rupturing, that is an emergency and they remove it so it won't. A ruptured spleen is life threatening. You can bleed to death very quickly.
So your ultrasound may have shown that you are getting into the danger zone but not there yet so you can wait to see the surgeon while the blood work is being processed.
Many thing can cause a spleen to blow up. But when it's so big it might rupture, they don't care. You can live without a spleen. You may not live if it ruptures.
so if it doesn't get too big and they can find the reason for it, they might be able to treat it and let it come back down. but if it gets too big and puts you in danger, better to take it out and then worry about why. things like mononucleosis can cause it. So can blood disorders. All sorts of things. But none of them are as serious as the possibility of your spleen rupturing while they try to treat you so they take care of the serious thing and then address the other stuff.
It's like trying to treat appendicitis with antibiotics. You get antibiotics and hope the appendix doesn't rupture(which can be life threatening) while the antibiotic kick in. It makes more sense to just take out the appendix and the infection that got into it will clear itself. Same with the spleen. If you get mono and your spleen blows up, don't worry about the mono...it will never kill you...but if your spleen ruptures, it will, so take out the spleen and recover from the mono after warRAB.
Does that make any sense to you?
Jenny