17 June - ITP

Today's case was a college student that has been followed for thrombocytopenia for ~ 1 year now.  His initial presentation was with a brief illness with subjective fevers and diarrhea and a transient, possibly petechial rash.  No bleeding occured.  CBC at student health revealed a PLT count of 23K.  He was admitted for workup and observation and was noted to have a prompt increase in PLT count (>50K at discharge).  Peripheral smear was unremarkable, HIV serology was negative, and overall clinical status was good.  He was diagnosed with ITP and discharged.  Over the following year his PLT count has fluctuated but never normalized.  He underwent bone marrow biopsy which was unremarkable.  He has had no bleeding events.

The ASH Image Bank has a complete case presentation with several representative images.  Nice review of clinical aspects of the topic.  Note the large platelet in the center of this image.

Pearls:

ITP is a diagnosis of exclusion - rule out TTP, leukemia, MDS, sepsis, etc.

ITP = immune thrombocytopenic purpura, not necessarily idiopathic...

There was a recently published international concensus statement on the w/u and management of ITP - published in: Blood, Vol. 115, Issue 2, 168-186, January 14, 2010

Some pearls:

Recommended testing for all adult patients includes peripheral smear, coombs test, Rh type, and serology for HCV, HIV, and H pylori. (I guess only infections that start with H cause ITP?)

Treatment rarely indicated for PLT counts >50K and no bleeding
First line therapy: anti-D immune globulin, steroids, and IVIG
Second line therapy: azathioprine, cyclosporine, cytoxan, vincristine, danazol, dapsone, rituxan, splenectomy
Salvage Therapy:  TPO receptor agonists, campath, chemo, HSCT