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

present.

 The pentad is: microangiopathic hemolytic anemia (MAHA), thrombocytopenia, renal

abnormalities, neurologic abnormalities, and fever

 Less than 50% of patients have the complete pentad

 Measurement of ADAMTS13 activity is not required to make the diagnosis; the

diagnosis is clinical

 The gold standard treatment is plasma exchange and if not available you may use fresh

frozen plasma as an alternative treatment

Pearl #3: Primary hemostasis disorders are a platelet dysfunction and secondary

hemostasis disorders are a clotting factor disorder.

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 Primary hemostasis Disorders:

o A result of platelet function

o Immediate clotting

o Patients will have petechiae and purpura

o All will have elevated bleeding time (platelets don’t work) and normal PT/PTT

(no problem with clotting factors)

 Secondary hemostasis Disorders:

o A result of clotting factors

o Delayed clotting (help strengthen clots by fibrin formation)

o Patients will have hematomas and hemarthroses

o All will have normal bleeding time (platelets work fine) and abnormal PT

(extrinsic pathway) and PTT (intrinsic pathway)

Pearl #4: Acute myelogenous leukemia (AML) type M3 has a good prognosis.

 AML is the most common type of acute leukemia in adults

 Typically M2 – M5 types are myeloperoxidase stain positive (Remember that PTU and

micropolyangitis can also be positive)

 Auer rods are pathognomonic for AML

 Type M3 (promyelocytic) leukemia has t(15,17)

 The treatment of choice is all-trans retinoic acid (ATRA)

 The single most important prognostic factor in AML is cytogentetics: t(15;17) has a 70%

5 year survival and 33% relapse rate

Pearl #5: Anemia is the most common hematologic abnormality, so know it cold.

 Iron deficiency anemia is the world’s most common cause of anemia

 Iron deficiency anemia:

o Low iron, transferrin saturation, and ferritin

o Elevated TIBC

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o Transferrin Receptor Index = transferrin receptor/Log Ferritin is the most

sensitive assay for iron deficiency anemia (>2.0 = Iron Deficiency Anemia; <1.0

= Anemia of Chronic Disease)

o Treatment is PO iron → if no improvement after 6 weeks consider IV iron

o The earliest lab to check after starting iron replacement is the reticulocyte count

(Begins to increase at about 5 to 7 days)

o Ascorbic acid (vitamin C) supplementation increases absorption of iron

o Most iron is absorbed in the duodenum

o Celiac sprue can cause iron deficiency anemia: Best test is tissue

transglutaminase antibody or antiendomysial antibody; Tx is a gluten free diet;

Can see dermatitis herpetiformis associated with this entity

As I have stated in my high yield pearls to pass the boards: “Most commons” are emphasized

on the ABIM curriculum, so it is good to know these disease processes. Also, diseases that

are increasing in incidence or have a high mortality associated with them are also high yield.

Anemia (most common hematologic abnormality), AML (most common acute leukemia in

adults), and Thrombotic Thrombocytopenic Purpura (high mortality) are 3 of the hematology

pearls covered in this post. Best of luck as you are preparing for your ABIM board exam, and

hopefully these pearls help you get a few more questions correct.

References:

1. George JN. How I Treat Patients With Thrombotic Thrombocytopenic Purpura: 2010.

Blood 2010 Nov; 116 (20): 4060 – 9. PMID: 20686117

2. Grimwalde D et al. The Importance of Diagnostic Cytogenetics on Outcome in AML:

Analysis of 1,612 patients entered into the MRC AML 10 Trial. The Medical Research

Council Adult and Children’s Leukemia Working Parties. Blood 1998 Oct; 92 (7): 2322

– 33. PMID: 9746770

3. Konrad G et al. Are Medication Restrictions Before FOBT Necessary?: Practical Advice

Based on a Systematic Review of the Literature. Can Fam Physician 2012 Sep; 58 (9):

939 – 48. PMID: 22972722

4. McDonnell WM et al. Effect of Iron on the Guaiac Reaction. Gastroenterology. 1989

Jan; 96 (1): 74 – 8. PMID: 2909440

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5. Rimon E et al. Diagnosis of Iron Deficiency Anemia in the Elderly by Transferrin

Receptor-Ferritin Index. Arch Intern Med 2002 Feb; 162 (4): 445 -9. PMID: 11863478

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