A 35-year-old man is brought to the emergency department by his roommate, who says that he has been acting "weird" for the past 2 days. The patient has spent most of the time in his room and has not been eating much. He has no headaches, focal weakness, or sensory symptoms. His medical history is significant for untreated HIV and hepatitis C infections. Temperature is 37.9 C (100.2 F), blood pressure is 140/86 mm Hg, pulse is 96/min, and respirations are 16/min. Mild scleral icterus is present. The oropharynx is normal and there is no nuchal rigidity. Examination of the chest and abdomen are unremarkable. Neurologic examination reveals no focal deficits. Laboratory results are as follows: A CT scan of the head with and without contrast reveals no abnormalities. Which of the following is the most appropriate next step in the management of this patient?

Question

A 35-year-old man is brought to the emergency department by his roommate, who says that he has been acting "weird" for the past 2 days.  The patient has spent most of the time in his room and has not been eating much.  He has no headaches, focal weakness, or sensory symptoms.  His medical history is significant for untreated HIV and hepatitis C infections.  Temperature is 37.9 C (100.2 F), blood pressure is 140/86 mm Hg, pulse is 96/min, and respirations are 16/min.  Mild scleral icterus is present.  The oropharynx is normal and there is no nuchal rigidity.  Examination of the chest and abdomen are unremarkable.  Neurologic examination reveals no focal deficits.  Laboratory results are as follows:  A CT scan of the head with and without contrast reveals no abnormalities.  Which of the following is the most appropriate next step in the management of this patient?

Quizplus · Accepted Answer

11ec25c8_d430_3a63_bc81_b505d0bca542_MD0003_00 Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder of the microvasculature characterized by the formation of small vessel thrombi that consume platelets, shear red blood cells, and often cause end organ damage (primarily renal and central nervous system). This patient has several manifestations of the classic pentad of TTP, which includes thrombocytopenia, microangiopathic hemolytic anemia (MAHA), renal insufficiency, neurologic changes (eg, acting "weird"), and fever. TTP is usually due to an acquired autoantibody to ADAMTS13, a plasma protease that cleaves von Willebrand factor (vWF) off the endothelial surface. As ADAMTS13 levels fall (due to the antibody), vWF multimers accumulate on the endothelial wall, trapping platelets at areas of high shearing force (eg, small arterioles, capillaries) and leading to the formation of thrombi. TTP is typically a disease of young adults (unlike hemolytic uremic syndrome, which primarily affects children) and is often idiopathic but may be triggered by infections (eg, HIV), malignancy, or medications. Diagnosis is based primarily on clinical and laboratory data. Evidence of thrombocytopenia and MAHA (eg, increased levels of indirect bilirubin, aspartate aminotransferase [AST], alanine aminotransferase [ALT], and lactate dehydrogenase, with a reticulocyte count >2.5%) should always raise suspicion for TTP. A manual peripheral blood smear is a crucial test in the diagnostic workup and would show signs of intravascular hemolysis (eg, schistocytes, helmet cells, triangle cells). peripheral blood smear Without treatment, the mortality rate from TTP is as high as 90%; therefore, TTP must be treated emergently with plasma exchange. Glucocorticoids are often added. (Choice A) Bone marrow biopsy is useful in the workup of unknown causes of anemia and thrombocytopenia. However, this patient has evidence of intravascular hemolysis and end organ damage, making TTP far more likely than a bone marrow issue. (Choice B) Flow cytometry can be used to measure CD4 counts in patients with HIV or to identify specific lymphocyte populations when certain types of lymphoma are suspected. Although obtaining a CD4 cell count would be useful in this patient with HIV, the fact that he has several classic manifestations of TTP should be addressed urgently, and TTP evaluation and management (eg, plasma exchange) takes precedence over CD4 cell count measurement. (Choices C and E) Severe liver pathology (eg, hepatitis C cirrhosis) may cause acute confusion (eg, encephalopathy). However, this patient's mild AST and ALT elevations, indirect hyperbilirubinemia, and significant anemia likely reflect intravascular hemolysis due to TTP, not intrinsic liver pathology requiring ultrasound evaluation or liver biopsy. Right upper quadrant ultrasound is also less likely to be useful, given that there is no evidence of gallbladder disease (indirect rather than direct hyperbilirubinemia). Educational objective: Thrombotic thrombocytopenic purpura should be suspected in patients with laboratory evidence of thrombocytopenia and intravascular hemolytic anemia. Neurologic changes and renal failure are often present at diagnosis. Peripheral blood smear is crucial in the diagnostic workup, demonstrating signs of intravascular hemolysis (eg, schistocytes).

A 35-Year-Old Man Is Brought to the Emergency Department by His