I would insure that the platelet count was done by hand. A lot of the time the problem isn't so much that the platelet count is low, rather that the platelets are large and the machines miss them.
I don't know about the petachae (I've never known how to spell that word!); Wallis had platelet issues but not that. She was tested for erhlicia but was negative, and even though she had a handful of problems the blood issues didn't seem to make them worse.
Good luck. I'm glad your baby is feeling so well at 10.
RIP Wallis, John Robert, Tibby & Pip
Mom to JoJo, Roxie & Linguini (Cavaliers)
and my birds Moji (Senegal) and Walter (Blue Front Amazon)