A 22-year-old hospitalized woman is evaluated for thrombocytopenia. Three days ago, she was hospitalized due to lower abdominal pain, vaginal bleeding, and fever. She was diagnosed with a septic abortion, was initiated on cefotetan and doxycycline, and underwent dilation and curettage. Platelet count at admission was 154,000/mm³; yesterday it was noted to be 89,000/mm³, with a further decrease on this morning's results. She has had no epistaxis or visible blood in the urine or stool but has had mild headache and fatigue. The patient has no known medical problems and no history of blood disorders.
Vital signs are normal. Physical examination shows scattered ecchymoses but is otherwise unremarkable, including benign abdominal and pelvic examinations.
Complete laboratory results from today are as follows:
Direct Coombs test is negative. Peripheral blood smear shows decreased platelets, polychromatophilic red blood cells, and multiple schistocytes with no platelet clumping.
Which of the following is the most likely cause of this patient's thrombocytopenia?

Question

A 22-year-old hospitalized woman is evaluated for thrombocytopenia. Three days ago, she was hospitalized due to lower abdominal pain, vaginal bleeding, and fever. She was diagnosed with a septic abortion, was initiated on cefotetan and doxycycline, and underwent dilation and curettage. Platelet count at admission was 154,000/mm³; yesterday it was noted to be 89,000/mm³, with a further decrease on this morning's results. She has had no epistaxis or visible blood in the urine or stool but has had mild headache and fatigue. The patient has no known medical problems and no history of blood disorders.
Vital signs are normal. Physical examination shows scattered ecchymoses but is otherwise unremarkable, including benign abdominal and pelvic examinations.
Complete laboratory results from today are as follows:

Direct Coombs test is negative. Peripheral blood smear shows decreased platelets, polychromatophilic red blood cells, and multiple schistocytes with no platelet clumping.
Which of the following is the most likely cause of this patient's thrombocytopenia?

Quizplus · Accepted Answer

11ec193a_96ea_a3a8_853d_ab64d795e844_MD0002_00 This patient likely has thrombotic thrombocytopenic purpura (TTP), which is characterized by the formation of small-vessel, platelet-rich thrombi due to severe deficiency of the von Willebrand factor-cleaving protein ADAMTS13. TTP can be associated with pregnancy due to the formation of autoantibodies (acquired) or the emergence of a previously unknown heredity case. Patients with TTP can be minimally symptomatic or critically ill but classically have: Severe thrombocytopenia (median platelet count ~10,000/mm³)Microangiopathic hemolytic anemia (MAHA) - schistocytes on peripheral blood smearOrgan dysfunction - thrombi-induced ischemia can lead to neurologic manifestations (eg, confusion, headache) and mild renal insufficiency (creatinine usually <2 mg/dL) Severe thrombocytopenia (median platelet count ~10,000/mm³) Severe thrombocytopenia (median platelet count ~10,000/mm³) ³ Microangiopathic hemolytic anemia (MAHA) - schistocytes on peripheral blood smear Microangiopathic hemolytic anemia (MAHA) - schistocytes on peripheral blood smear Organ dysfunction - thrombi-induced ischemia can lead to neurologic manifestations (eg, confusion, headache) and mild renal insufficiency (creatinine usually <2 mg/dL) Organ dysfunction - thrombi-induced ischemia can lead to neurologic manifestations (eg, confusion, headache) and mild renal insufficiency (creatinine usually <2 mg/dL) Diagnostic evaluation usually reveals normal coagulation studies (unlike disseminated intravascular coagulation [DIC]), negative Coombs testing, and ADAMTS13 levels of <10%. Urgent treatment with plasma exchange, glucocorticoids, and rituximab are required to prevent death. (Choice A) Antiphospholipid antibody syndrome (APS) is commonly associated with pregnancy complications (eg, embryonic loss) and arterial/venous thrombosis. Although mild thrombocytopenia can occur, severe thrombocytopenia and MAHA are uncommon, including with catastrophic APS, which can cause multisystem failure (eg, severe hypertension and proteinuria, acute respiratory distress syndrome, altered mental status). (Choice B) DIC often arises in the setting of sepsis or obstetrical complications and is frequently associated with MAHA and moderate thrombocytopenia. However, platelet counts <20,000/mm³ are uncommon, and patients with DIC have abnormal coagulation studies (eg, prolonged PT/PTT). ³ (Choice C) Drug-induced immune thrombocytopenia can cause severe thrombocytopenia but is not typically associated with MAHA or other cytopenias (eg, anemia). (Choice D) Idiopathic thrombocytopenic purpura (also called immune thrombocytopenia) is more common in pregnancy and can cause severe thrombocytopenia. However, this condition is not associated with MAHA. Educational objective: Pregnancy can cause thrombotic thrombocytopenic purpura (TTP) due to either the formation of autoantibodies or the emergence of a previously undiagnosed hereditary case. Patients can be minimally symptomatic or critically ill, but laboratory evaluation typically shows severe thrombocytopenia and microangiopathic hemolytic anemia. Unlike disseminated intravascular coagulation, TTP is usually associated with normal coagulation studies. __________ References: Drug-induced thrombocytopenia: pathogenesis, evaluation, and management. (http://www.ncbi.nlm.nih.gov/pubmed/20008194) Thrombotic thrombocytopenic purpura and pregnancy: presentation, management, and subsequent pregnancy outcomes. (http://www.ncbi.nlm.nih.gov/pubmed/24859360)

A 22-Year-Old Hospitalized Woman Is Evaluated for Thrombocytopenia