High -Yield Internal Medicine Board Exam Pearls by Knowmedge - HTML preview

5 Hematology Pearls

By Dr. Salim Rezaie

Hematology is a subject that comes up daily in clinical practice, and is a favorite on the ABIM

Internal Medicine board exam. Evaluation of anemia, as well as some other hematologic

disorders, is paramount for an internist to master. I will try and provide five evidence-based

pearls in this post that will help physicians understand some important concepts and avoid

common pitfalls in the recognition and treatment of such hematological disorders.

Pearl #1: Patients on iron supplementation SHOULD NOT have positive guaiac tests.

 Studies in vitro show ferric iron (Fe3+) will give a positive guaiac reaction and ferrous

iron (Fe2+) does not

 Iron is digested in the ferrous form and carried in the blood in the ferric form

 Patients on iron supplementation with positive guaiac require screening for identifying

the source of gastrointestinal hemorrhage

 Ferrous (Fe2+) iron does not cause positive guaiac tests in vivo

Pearl #2: The pentad of Thrombotic Thrombocytopenic Purpura (TTP) is not always