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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor={{Rim}}, {{AJL}} {{Alison}}
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Immunology
|MainCategory=Immunology
Line 20: Line 20:
|MainCategory=Immunology
|MainCategory=Immunology
|SubCategory=Hematology
|SubCategory=Hematology
|Prompt=A 67 year old male patient presents to the physician's office complaining of weight loss, fever, and night sweats. Following appropriate work-up, he is diagnosed with acute myelogenous leukemia (AML) and is started on scheduled chemotherapy sessions. Several weeks later, the patient is found to have profound thrombocytopenia. The physician decides to transfuse platelets. During the transfusion, the patient experiences fever, chills, and intense flushing. He denies any itching or shortness of breath. Vital signs are remarkable for temperature of 38.4 degrees C (101 degrees F), heart rate of 108 bpm, respiratory rate of 18/min, and blood pressure measuring 128/78 mmHg. What is the most likely cause of this patient's reaction to the platelet transfusion?
|Prompt=A 67-year-old male presents to the physician's office complaining of weight loss, fever, and night sweats. Following appropriate work-up,you diagnose him with acute myelogenous leukemia (AML) and start him on scheduled chemotherapy sessions. Several weeks later, you find that the patient is experiencing profound thrombocytopenia, requiring platelet transfusion. During the transfusion, the patient develops fever, chills, and intense flushing, but denies any itching or shortness of breath. Upon physical exam you find that the patient has a temperature of 38.4 °C, heart rate of 108 bpm, respiratory rate of 18/min, and blood pressure measuring 128/78 mmHg. What is the most likely cause of this patient's reaction to the platelet transfusion?
|Explanation=The patient is most likely presenting with febrile nonhemolytic transfusion reaction (FNHTR). Most cases of FNHTR occur in platelet transfusions. The pathogenesis of the platelet reactions is due to cytokines that are present in the product during storage. The true mechanism of the accumulation and the pathophysiology of the condition is poorly understood. Cytokines generally mediate a reaction whereby antibodies are directed against donor leukocytes and HLA antigens. In packed red blood cells, the pathophysiology is believed to be mostly caused by recipient white blood cell activation against transfused leukocytes and subsequent release of endotoxins that cause fever. Treatment is still controversial, but includes fever reduction by antipyretics (such as acetaminophen). Stopping the transfusion is also generally done. Prevention may be accomplished by acetaminophen and diphenhydramine.
|Explanation=The patient in this scenario most likely presents with a [[febrile nonhemolytic transfusion reaction|febrile nonhemolytic transfusion reaction (FNHTR)]]. Most cases of [[FNHTR]] occur in platelet transfusions. Pathogenesis of the platelet reactions is mediated by cytokines within the product. Cytokines facilitate the reactions, while antibodies are directed against donor leukocytes and HLA antigens. In packed red blood cells, the pathophysiology is believed to be caused by the activation of recipient leukocytes against transfused erythrocytes and the subsequent release of endotoxins, causing fever that is often managed by antipyretics (such as acetaminophen). The use of acetaminophen and diphenhydramine can help minimize the risk of developing [[FNHTR]].


Educational Objective:
|EducationalObjectives= [[Febrile nonhemolytic transfusion reaction|Febrile nonhemolytic transfusion reaction (FNHTR)]], characterized by fever and flushing, most frequently occurs following platelet transfusions.
Febrile nonhemolytic transfusion reaction (FNHTR), characterized by uncomplicated fever and flushing, is most likely due to activation of recipient WBCs against transfused leukocytes and subsequent release of endotoxins.
|References= Tenorio GC, Gupte SC, Munker R. Transfusion medicine and immunohematology. in Modern Hematology - Biology and Clinical Management, 2nd ed. 2007. pp:401-432.


Reference:
Heddle NM. Pathophysiology of febrile nonhemolytic transfusion reactions. Curr Opin Hematol. 1999; 6(6):420-6.
Tenorio GC, Gupte SC, Munker R. Transfusion medicine and immunohematology. in Modern Hematology - Biology and Clinical Management, 2nd ed. 2007. pp:401-432.


Heddle NM. Pathophysiology of febrile nonhemolytic transfusion reactions. Curr Opin Hematol. 1999; 6(6):420-6.
|AnswerA=Formation of IgG and IgA immune complexes that activate the complement pathway and release C3a and C5a
|AnswerA=Formation of IgG and IgA immune complexes that activate the complement pathway and release C3a and C5a
|AnswerAExp=Anaphylactic reaction, usually in patients with IgA deficiency, is caused by formation of immune complexes that activate anaphylaxins, such as C3a and C5a. Patients typically present with features of anaphylaxis, such as hypotension and shock.
|AnswerAExp= Anaphylactic reaction, usually occurring in patients with IgA deficiency, is caused by formation of immune complexes that activate anaphylaxins, such as C3a and C5a. Patients typically present with features characteristic of anaphylaxis, such as hypotension and shock.
|AnswerB=Reaction caused primarily by the accumulation of cytokines in the platelet products during storage
|AnswerB=Reaction caused primarily by the accumulation of cytokines in the platelet products during storage
|AnswerBExp=In platelet transfusions, febrile nonhemolytic transfusion reaction (FNHTR) is most likely due to cytokine-mediated targeting of antibodies against donor leukocytes and HLA antigens. Cytokines accumulate during the storage of platelet products.
|AnswerBExp= See explanation.
|AnswerC=Hypersensitivity reaction against foreign antigens on donor red blood cells
|AnswerC=Hypersensitivity reaction against foreign antigens on donor red blood cells
|AnswerCExp=Acute and delayed hemolytic transfusion reactions are caused by hypersensitivity reactions against foreign antigens on donor red blood cells. Features of hemolysis, such as jaundice, flank pain, and hemoglobinuria, are frequently present.
|AnswerCExp= Acute and delayed hemolytic transfusion reactions, resulting from hypersensitivity reactions against foreign antigens on donor red blood cells, manifest in jaundice, flank pain, and hemoglobinuria.
|AnswerD=Production of IgE by plasma cells following antigen exposure
|AnswerD=Production of IgE by plasma cells following antigen exposure
|AnswerDExp=Allergic reaction is caused by IgE production by plasma cells following antigen exposure. Urticaria, pruritis, and wheezing are usually present.
|AnswerDExp= Following antigen exposure, allergic reaction may result from IgE production by plasma cells. The allergic reaction typically manifest with urticaria, pruritis, and wheezing.
|AnswerE=Non-immune circulatory overload due to rapidly incoming transfused blood
|AnswerE=Non-immune circulatory overload due to rapidly incoming transfused blood
|AnswerEExp=Transfusion-associated circulatory overload (TACO) is caused by rapid transfusion of blood products. It is non-immune condition that causes high blood pressure, peripheral edema, dyspnea, and orthopnea.
|AnswerEExp= Transfusion-associated circulatory overload (TACO) results from the rapid transfusion of blood products. TACO is a non-immune condition, which typically causes high blood pressure, peripheral edema, dyspnea, and orthopnea.
|RightAnswer=B
|RightAnswer=B
|WBRKeyword=transfusion, reaction, hemolytic, hemolysis, nonhemolytic, fever, shock, anaphylaxis, warfarin, gastrointestinal, GI, bleeding, TACO, transfusion, associated, circulatory, overload
|WBRKeyword=transfusion, reaction, hemolytic, hemolysis, nonhemolytic, fever, shock, anaphylaxis, warfarin, gastrointestinal, GI, bleeding, TACO, transfusion, associated, circulatory, overload
|Approved=No
|Approved=Yes
}}
}}

Revision as of 18:58, 11 July 2014
Author [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Immunology
Sub Category SubCategory::Hematology
Prompt [[Prompt::A 67-year-old male presents to the physician's office complaining of weight loss, fever, and night sweats. Following appropriate work-up,you diagnose him with acute myelogenous leukemia (AML) and start him on scheduled chemotherapy sessions. Several weeks later, you find that the patient is experiencing profound thrombocytopenia, requiring platelet transfusion. During the transfusion, the patient develops fever, chills, and intense flushing, but denies any itching or shortness of breath. Upon physical exam you find that the patient has a temperature of 38.4 °C, heart rate of 108 bpm, respiratory rate of 18/min, and blood pressure measuring 128/78 mmHg. What is the most likely cause of this patient's reaction to the platelet transfusion?]]
Answer A AnswerA::Formation of IgG and IgA immune complexes that activate the complement pathway and release C3a and C5a
Answer A Explanation [[AnswerAExp::Anaphylactic reaction, usually occurring in patients with IgA deficiency, is caused by formation of immune complexes that activate anaphylaxins, such as C3a and C5a. Patients typically present with features characteristic of anaphylaxis, such as hypotension and shock.]]
Answer B AnswerB::Reaction caused primarily by the accumulation of cytokines in the platelet products during storage
Answer B Explanation AnswerBExp::See explanation.
Answer C AnswerC::Hypersensitivity reaction against foreign antigens on donor red blood cells
Answer C Explanation AnswerCExp::Acute and delayed hemolytic transfusion reactions, resulting from hypersensitivity reactions against foreign antigens on donor red blood cells, manifest in jaundice, flank pain, and hemoglobinuria.
Answer D AnswerD::Production of IgE by plasma cells following antigen exposure
Answer D Explanation AnswerDExp::Following antigen exposure, allergic reaction may result from IgE production by plasma cells. The allergic reaction typically manifest with urticaria, pruritis, and wheezing.
Answer E AnswerE::Non-immune circulatory overload due to rapidly incoming transfused blood
Answer E Explanation AnswerEExp::Transfusion-associated circulatory overload (TACO) results from the rapid transfusion of blood products. TACO is a non-immune condition, which typically causes high blood pressure, peripheral edema, dyspnea, and orthopnea.
Right Answer RightAnswer::B
Explanation [[Explanation::The patient in this scenario most likely presents with a febrile nonhemolytic transfusion reaction (FNHTR). Most cases of FNHTR occur in platelet transfusions. Pathogenesis of the platelet reactions is mediated by cytokines within the product. Cytokines facilitate the reactions, while antibodies are directed against donor leukocytes and HLA antigens. In packed red blood cells, the pathophysiology is believed to be caused by the activation of recipient leukocytes against transfused erythrocytes and the subsequent release of endotoxins, causing fever that is often managed by antipyretics (such as acetaminophen). The use of acetaminophen and diphenhydramine can help minimize the risk of developing FNHTR.

Educational Objective: Febrile nonhemolytic transfusion reaction (FNHTR), characterized by fever and flushing, most frequently occurs following platelet transfusions.
References: Tenorio GC, Gupte SC, Munker R. Transfusion medicine and immunohematology. in Modern Hematology - Biology and Clinical Management, 2nd ed. 2007. pp:401-432.

Heddle NM. Pathophysiology of febrile nonhemolytic transfusion reactions. Curr Opin Hematol. 1999; 6(6):420-6.]]

Approved Approved::Yes
Keyword WBRKeyword::transfusion, WBRKeyword::reaction, WBRKeyword::hemolytic, WBRKeyword::hemolysis, WBRKeyword::nonhemolytic, WBRKeyword::fever, WBRKeyword::shock, WBRKeyword::anaphylaxis, WBRKeyword::warfarin, WBRKeyword::gastrointestinal, WBRKeyword::GI, WBRKeyword::bleeding, WBRKeyword::TACO, WBRKeyword::transfusion, WBRKeyword::associated, WBRKeyword::circulatory, WBRKeyword::overload
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