A 45-year-old woman comes to the emergency department due to worsening fatigue. Today, she was so tired that she became short of breath doing household chores. She has also had "spots" on her extremities and seems to bruise very easily. The patient has had no fever, night sweats, cough, chest pain, palpitations, or abdominal pain. She has no chronic medical problems and has had no recent cold or flu symptoms. She does not take any medications and does not use tobacco, alcohol, or illicit drugs. Temperature is 38 C (100.4 F), blood pressure is 110/60 mm Hg, pulse is 92/min, and respirations are 16/min. Physical examination shows moist mucous membranes, clear lung fields, and normal heart sounds. The abdomen is soft and nontender with no hepatosplenomegaly. Neurologic examination is within normal limits. The extremities have no edema, but there are scattered petechiae and ecchymoses bilaterally. Laboratory results are as follows: Chest x-ray is normal. A peripheral blood smear is shown in the exhibit. Which of the following is the goal of the first-line therapy for this patient's current condition?

Question

A 45-year-old woman comes to the emergency department due to worsening fatigue.  Today, she was so tired that she became short of breath doing household chores.  She has also had "spots" on her extremities and seems to bruise very easily.  The patient has had no fever, night sweats, cough, chest pain, palpitations, or abdominal pain.  She has no chronic medical problems and has had no recent cold or flu symptoms.  She does not take any medications and does not use tobacco, alcohol, or illicit drugs.  Temperature is 38 C (100.4 F), blood pressure is 110/60 mm Hg, pulse is 92/min, and respirations are 16/min.  Physical examination shows moist mucous membranes, clear lung fields, and normal heart sounds.  The abdomen is soft and nontender with no hepatosplenomegaly.  Neurologic examination is within normal limits.  The extremities have no edema, but there are scattered petechiae and ecchymoses bilaterally.  Laboratory results are as follows:  Chest x-ray is normal.  A peripheral blood smear is shown in the exhibit.  Which of the following is the goal of the first-line therapy for this patient's current condition?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bf82_7173_8f63_c7e79ac0d8b1_MD0005_00 This patient with fatigue and bruising has microangiopathic hemolytic anemia (MAHA), severe thrombocytopenia, and normal coagulation studies, indicating likely thrombotic thrombocytopenic purpura (TTP). TTP is an acquired syndrome due to the formation of autoantibodies against ADAMTS13, a plasma metalloprotease responsible for cleaving ultralarge strings of von Willebrand factor (vWF) off the vascular endothelial wall. When levels of ADAMTS13 become severely deficient, uncleaved strings of vWF trap and activate platelets, resulting in diffuse microvascular thrombi. This causes the following: Platelet consumption, leading to severe thrombocytopenia Intravascular red blood cell shearing, leading to signs of MAHA such as schistocytes and elevated indirect bilirubin, lactate dehydrogenase, and aminotransferases Organ ischemia, leading to neurologic and renal dysfunction (classically) Patients who have clinical and laboratory data that support the diagnosis of TTP require urgent treatment with plasma exchange. This removes the autoantibody against ADAMTS13 and replenishes the enzyme with ADAMTS13 from donor serum. (Choice A) Desmopressin increases serum concentrations of vWF and is often used in von Willebrand disease to stop minor episodes of bleeding. Patients with this disease may have easy bruising and petechiae, but MAHA is uncommon. (Choice C) Patients with disseminated intravascular coagulation usually have signs of thrombocytopenia and MAHA due to coagulation cascade activation. However, disseminated intravascular coagulation is usually associated with prolonged coagulation testing, unlike this patient. (Choice D) Antibodies against platelet antigens are responsible for immune thrombocytopenia, which may cause thrombocytopenia, bruising, and petechiae. However, immune thrombocytopenia is not associated with MAHA. (Choice E) Platelet transfusions are not recommended for patients with TTP unless severe bleeding occurs. The additional platelets may worsen the ongoing intravascular thrombosis. Educational objective: Thrombotic thrombocytopenic purpura is due to acquired autoantibodies against the metalloprotease ADAMTS13, which cleaves ultralarge chains of von Willebrand factor off the vascular endothelium. Uncleaved chains trap and activate platelets, resulting in severe thrombocytopenia and microangiopathic hemolytic anemia (eg, schistocytes, elevated indirect bilirubin). Urgent treatment with plasma exchange removes the autoantibody and replenishes ADAMTS13. References: Optimal preprocedural platelet transfusion threshold for central venous catheter insertions in patients with thrombocytopenia. (http://www.ncbi.nlm.nih.gov/pubmed/21517892)

A 45-Year-Old Woman Comes to the Emergency Department Due to Worsening