Hi Jody and welcome to HW!
I am Kathy, I have a set of twins that have CF. Both of which went thru the same thing as your son from birth till diagnosed. I will list some of the symptoms at the end of this post.
I know you said your son was 2, but, the info I am going to explain to you starts from a baby. Usually, mostly only babies have RSV but can linger on for a very long time.
First of all, there are many things to consider when having RSV for "any" baby. Not all babies have CF just because they have RSV or even pneumonia. It's a very hard thing to overcome but can be done with proper treatment. A pulmonologist will get your son back on track "quickly" I can assure you of that. It takes alot of determination on your part to overcome this hump so stick with the plan that the doctor sets out for you. Please don't feel scared if the doctors want to do aggressive treatment, it HAS to be done!. It's possible they might have to hospitalize your son to get the oxygen level back to normal, perhaps expect this on their agenda.
Things to consider a baby or child with CF has. Greasy stools, looks like grease (orange or frothy color). Distended belly and very hard, often screaming and turning blue after eating. Failure to thrive, no weight gain. Hard to burp and have to work and work to get a burp. Very salty/irony taste on the skin. A starvation appearance. Go to the site CF organization for more information, there is a lot of great info out there. I cannot post the link here due to forum rules.
If these things are occurring, I perhaps can help you thru some hard times while your waiting to see a pulmonologist.
Be patient mom, things are gonna get better soon with the help of the pulmonologist. It will be a long hard road to overcome RSV, but, it can be done. It took me 2 yrs for my babies to stop wheezing and get over that hump. Please, don't expect overnight changes.
As far as testing for CF. There is a test called a sweat chloride test. It does not hurt to have it done. It's a little aggrivating for your child. The results are immediate.
Good luck and keep us posted. Try not to worry because things will improve soon.
Kathy, mom to identical twin boys with CF (9yrs), daughter 20, grandaughter 2 1/2, one on the way!
If there is a CURE for Cystic Fibrosis this very moment and this is "not soon enough"...you would hear this twins mom "Across America" "YESSSSSSSSSS"!!.
Moderator, Cystic Fibrosis. "If there is questionable doubt, check it out"....with your healthcare provider!. We are here to offer support, encouragement, and answer your questions as best we can. Don't hesitate to step on in and enjoy!.