A 32-year-old woman comes to the office due to several days of fatigue and malaise. She has no significant medical history and has had no recent sick contacts. The patient does not appear to be in acute distress. Evaluation reveals severe thrombocytopenia. Thrombotic thrombocytopenic purpura is suspected. Which of the following findings is required to make the diagnosis?

Question

A 32-year-old woman comes to the office due to several days of fatigue and malaise.  She has no significant medical history and has had no recent sick contacts.  The patient does not appear to be in acute distress.  Evaluation reveals severe thrombocytopenia.  Thrombotic thrombocytopenic purpura is suspected.  Which of the following findings is required to make the diagnosis?

Quizplus · Accepted Answer

11ec160b_3af9_e6a7_9249_bd7f7142f8c6_MD0001_00 Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy characterized by the formation of platelet-rich thrombi in the microvasculature. It is caused by severe deficiency of ADAMTS13, an enzyme that cleaves ultra-large von Willebrand factor multimers on the endothelial surface. Loss of ADAMTS13 triggers spontaneous platelet aggregation and activation, which results in thrombocytopenia due to platelet consumption and microangiopathic hemolytic anemia (MAHA) due to mechanical shearing of passing red blood cells. Acquired TTP (autoantibody against ADAMTS13) was initially described as a pentad of fever, neurologic symptoms, kidney disease, MAHA, and thrombocytopenia. However, up to one-third of patients do not have neurologic abnormalities, half have normal kidney function, and only one-fifth have fever (Choices A, C, and F). In fact, many with acquired TTP have minimal signs of toxicity (as in this case). Therefore, the only factors required for further evaluation of suspected thrombotic microangiopathy (eg, TTP, HUS) are the presence of thrombocytopenia and MAHA on peripheral blood smear (eg, schistocytes); significantly reduced ADAMTS13 activity can help confirm a specific diagnosis of TTP. Plasma exchange is life-saving and should be considered in patients who have MAHA and thrombocytopenia and in whom TTP is suspected (untreated patients have a mortality rate of up to 90%). (Choice B) Liver aminotransferases can sometimes be elevated in hemolytic anemia because these enzymes are present in erythrocytes. However, in this case, elevated aminotransferases are a nonspecific finding that would not be useful for confirming the presence of a thrombotic microangiopathy such as TTP. (Choice E) Coombs testing evaluates for the presence of immunoglobulin on the erythrocyte surface. In TTP, the hemolytic anemia is triggered by red blood cell shearing in the microvasculature, not immunoglobulin attachment; therefore, Coombs testing would be unrevealing. Educational objective: Thrombotic thrombocytopenic purpura is a thrombotic microangiopathy resulting in microangiopathic hemolytic anemia and thrombocytopenia, findings that are essential for making the diagnosis. It is triggered by severe deficiency in ADAMTS13 levels. __________ References: How I treat thrombotic thrombocytopenic purpura and atypical haemolytic uraemic syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/24387053) Management of thrombotic thrombocytopenic purpura: current perspectives. (http://www.ncbi.nlm.nih.gov/pubmed/24523598)

A 32-Year-Old Woman Comes to the Office Due to Several