The stress is tough to avoid during uncertainty and more so under extreme uncertainty. The main issue, imo, is that ITP can only be identified via elimination of all the other identifiable causes of low platlets. Until I was identified with ITP in 2000 my only memory of platlets with High School biology. ITP is also very, very rare so I doubt MD's will embrace it to quickly. The marrow aspiration is one test in the process of elimination. Don't freak on this and I hope the MD at least mentioned why the marrow test. It's because Leukemia can also cause the bruising and platlets are created in our marrow. I didn't have a problem with that actual test although it sounds scary. We all have a "soft" spot in our hip which is the easiest place to insert a syringe to extract bone marrow for testing. Mine was done right in the hospital bed. Laid on my side, they numbed the area and pushed really hard. Some experience pain or simple discomfort, mine was pretty uneventful. The elimination of that as a cause is just another step before admitting it's ITP (unknown blood disorder of the auto immune system). They should also quiz you about all the herbs and/or health foods you might consume as they can lower platlets. Certain drugs (aspirin, alcohol and others can decrease platlets) thou I don't know their amount of influence.
Your steroid Rx was very short compared to many of us. In the hospital I was on 1000mg and tapered off over months. The theory is to reset our immune system by turning it way down and allow it to "reset" during the taper (didn't work for me). BTW, I've relapsed after 10y and I'm now on 100mg tapering over 4 months. I wouldn't be surprised if you went onto an aggressive protocol if ITP becomes the Diagnosis.
"Normal" platelet counts are 200,000 - 400,000 (typically expressed simply as 200 -400). Less than 100 is reason for concern, < 30 is reason for significant concern (my first Dx was 24k and landed at 0). Many people here are living quite well (other than anxiety and frustration) at > 50.
Another personal factor is I had no idea of what my normal count was - who pays attention unless there's a specific reason to.
Visit often, ask questions frequently as knowledge is power but not necessarily comfort. NO question is to foolish and ALL of us have been there.
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Blessings of enough...
Faith to trust our Lord
Joy to share with others
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Love to share with the hurting
Steve C