I think I started a thread last yr about something like this. I called SSA and they said I was disabled with A and B or just A or just B. In my approval letter it also mentioned another impairment(non-disabling) which wasn't listed as A or B. This impairment is kicking into full gear plus I am just starting another impairment which progressively gets worse.
A PCP can't officially declare someone disabled since they aren't a specialist. They recommended my specialists. They are sorta a watchdog for your other aliments. I don't know if SSA considers a PCP important as far as your impairments are concerned.
I may never get reviewed because of my age ,but I guess there is always that chance.