A 41-year-old man comes to the emergency department due to 3 days of fever, chills, and nonproductive cough. The patient has also felt tired and weak during this period. He has a history of injection drug use and has been hospitalized several times for injection site cellulitis. Temperature is 38.3 C (101 F), blood pressure is 125/72 mm Hg, and pulse is 112/min and regular. Cardiopulmonary auscultation reveals scattered rhonchi and a cardiac murmur, which were not previously present. Laboratory evaluation shows leukocytosis, and chest x-ray reveals nodular opacities. Echocardiography of this patient is most likely to reveal which of the following findings?

Question

A 41-year-old man comes to the emergency department due to 3 days of fever, chills, and nonproductive cough.  The patient has also felt tired and weak during this period.  He has a history of injection drug use and has been hospitalized several times for injection site cellulitis.  Temperature is 38.3 C (101 F), blood pressure is 125/72 mm Hg, and pulse is 112/min and regular.  Cardiopulmonary auscultation reveals scattered rhonchi and a cardiac murmur, which were not previously present.  Laboratory evaluation shows leukocytosis, and chest x-ray reveals nodular opacities. Echocardiography of this patient is most likely to reveal which of the following findings?

Quizplus · Accepted Answer

11ec160b_3aa5_373d_9249_95bc3fc71cf4_MD0001_00 Vancomycin inhibits cell wall synthesis of gram-positive bacteria by binding to the D-Alanine-D-Alanine terminus of nascent peptidoglycan pentapeptides, thereby inhibiting peptidoglycan elongation and cross-linking. Although vancomycin is generally well tolerated, a minority of patients develop "red man" syndrome (RMS), a non-allergic drug reaction that occurs when vancomycin is infused too rapidly. RMS arises due to the direct activation of mast cells by vancomycin, which results in the release of vasoactive mediators (eg, histamine). Manifestations typically arise within seconds/minutes of vancomycin infusion and include flushing, erythema, and pruritis, primarily in the neck and upper torso. Most cases resolve spontaneously with the cessation of vancomycin and the administration of diphenhydramine. Because RMS is not a true allergic reaction (not Ig-E mediated), vancomycin can be safely resumed at a slower rate once the symptoms have resolved. (Choice A) Gentamicin, an aminoglycoside antibiotic, is associated with ototoxicity and nephrotoxicity. (Choices B and C) Beta-lactam antibiotics (eg, imipenem, penicillin) generally cause IgE-mediated hypersensitivity reactions. In allergic reactions, histamine release is not linked to infusion rate, and patients usually have a history of previous exposure. (Choice D) Trimethoprim-sulfamethoxazole can occasionally cause megaloblastic anemia, thrombocytopenia, leukopenia, and/or toxic epidermal necrolysis. Educational objective: Rapid infusion of vancomycin can lead to the direct activation of mast cells, which results in a massive release of histamine. This causes "red man" syndrome, a nonallergic reaction marked by flushing, erythema, and pruritis within seconds or minutes of vancomycin infusion. Because this reaction is not IgE-mediated, vancomycin can be safely resumed at a slower rate once symptoms have resolved.

A 41-Year-Old Man Comes to the Emergency Department Due to 3