WBR0458

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::Hematology, SubCategory::Oncology
Prompt	[[Prompt::A 24 year old male patient presents to the physician’s office complaining of fatigue, unremitting fever, and easy bruisability with minor trauma. His vital signs show a temperature of 38.6 degrees C (101.5 degrees F), heart rate of 98 beats per minute, and blood pressure measuring 116/82 mmHg. His physical examination was remarkable for pallor, bleeding gums, and purpura. An image of the patient’s peripheral blood smear is shown below. Following the initiation of appropriate treatment, the patient suffers a complication. Which of the following best characterized the patient’s complication? ]]
Answer A	AnswerA::Activation of hemostasis and fibrinolysis that lead to formation of thrombin and plasmin
Answer A Explanation	AnswerAExp::DIC is characterized by the activation of hemostasis and fibrinolysis that lead to formation of thrombin and plasmin.
Answer B	AnswerB::Autoimmune antibodies against platelets
Answer B Explanation	AnswerBExp::Idiopathic thrombocytopenic purpura (ITP) is characterized by autoimmune antibodies against platelets that typically occur following a viral illness.
Answer C	AnswerC::Systemic deposition of platelet thrombi with abundant von Willebrand factor (vWF) in arterioles and capillaries
Answer C Explanation	AnswerCExp::Thrombotic thrombocytopenic purpura (TTP) is characterized by the systemic deposition of platelet thrombi with abundant von Willebrand factor (vWF) in arterioles and capillaries.
Answer D	AnswerD::Increased ristocetin sensitivity
Answer D Explanation	AnswerDExp::von Willebrand’s disease (vWD) is characterized by increased sensitivity to ristocetin.
Answer E	AnswerE::Monoclonal gammopathy of undetermined significance
Answer E Explanation	[[AnswerEExp::Monoclonal gammopathy of undetermined significance (MGUS) is a hematologic condition that is characterized by the presence of monoclonal antibodies without having clinical symptoms, or radiological and laboratory signs. The disease is similar to multiple myeloma (MM), but unlike MM, the number of monoclonal plasma cells in MGUS is lower constituting less than 10% of bone marrow biopsy findings. MGUS requires no treatment. Monitoring for the evolution of MGUS into MM is important because rate of MM development is approximately 1-2% in patients with MGUS.]]
Right Answer	RightAnswer::A
Explanation	[[Explanation:: The patient is presenting with acute promyelocytic leukemia (APML) or AML M3. Symptoms of AML M3 are typically unremitting fever with signs of pancytopenia: Anemia as manifested by pallor, thrombocytopenia as manifested by easy bruisibility and purpura, and leucopenia as manifested by sore throat, pneumonia, or other infections. On peripheral smear, AML M3 is characterized by Auer rods. The image above shows one Auer rod in circle; the image contains several other examples that are not circled. Treatment of AML M3 by all-trans retinoic acid causes the release of Auer rods and potentially might cause disseminted intravascular coagulation (DIC). DIC is a complication of several diseases, including AML M3. In the latter, DIC occurs following treatment DIC is characterized by activation of the hemostasis system with release of tissue factor mostly from endothelial cells. Normally, the inhibitor system compensates for the tissue factor release, but as the injury persists, eventual consumption of inhibitors occurs and more coagulation ensues in a process called “consumptive coagulopathy”. As a result, the entire hemostasis pathway becomes unbalanced and breaks down. Symptoms of DIC include profuse bleeding with blood work-up revealing low fibrinogen, with elevated levels of D-dimer and fibrinogen split products (FSP), suggesting the generation of plasmin. Consumptive coagulopathy is corrected by cryoprecipitate, platelet concentrations, and fresh frozen plasma (FFP) to help reduce the tendency to bleed. Educational Objective: AML M3 is characterized by pancytopenia and fever with peripheral blood smear showing plasma cells containing Auer rods. DIC is a common complication following treatment of AML M3 due to release of Auer rods. DIC is a consumptive coagulopathy that is caused by the imbalance of hemostasis and fibrinolytic pathway. Reference: Mammen EF. Disseminated intravascular coagulation (DIC). Clin Lab Sci. 2000;13(4):239-45 Educational Objective: References: ]]
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