A 33-year-old man comes to the emergency department due to fever, chills, cough, and shortness of breath over the last week. He smokes a pack of cigarettes a day, consumes 2 or 3 alcoholic beverages daily, and uses intravenous heroin 2 or 3 times per week. He is febrile and tachycardic. Blood cultures grow Staphylococcus aureus. Chest x-ray shows bilateral nodular lesions with areas of cavitation. The valve most likely affected in this patient can be best evaluated by auscultation at which of the following sites?

Question

A 33-year-old man comes to the emergency department due to fever, chills, cough, and shortness of breath over the last week.  He smokes a pack of cigarettes a day, consumes 2 or 3 alcoholic beverages daily, and uses intravenous heroin 2 or 3 times per week.  He is febrile and tachycardic.  Blood cultures grow Staphylococcus aureus.  Chest x-ray shows bilateral nodular lesions with areas of cavitation.  The valve most likely affected in this patient can be best evaluated by auscultation at which of the following sites?

Quizplus · Accepted Answer

11ec160b_3568_942c_9249_2960a9dca6cb_MD0001_00 The cavitary pulmonary nodules on this patient's chest x-ray are consistent with septic emboli, which are a common complication of right-sided infective endocarditis (IE). The tricuspid valve is frequently affected in intravenous drug users; bacterial adherence may be encouraged by the inadvertent injection of particulate matter that damages the tricuspid valve endothelium. Staphylococcus aureus is the most common organism responsible for IE in intravenous drug users. A murmur of IE typically results from regurgitation of blood due to impaired closure of the affected valve. Although tricuspid valve endocarditis does not always cause a murmur, an early- or holo-systolic murmur of tricuspid regurgitation is sometimes appreciated. This murmur is best auscultated in the 4th or 5th intercostal space at the left lower sternal border (the tricuspid auscultation area), and it increases in intensity with maneuvers that increase right ventricular blood volume (eg, inspiration, supine leg raise). (Choices A and D) Most aortic valve murmurs are best auscultated in the 2nd intercostal space at the right upper sternal border. Mitral valve murmurs are best auscultated at the cardiac apex, which is usually located near the midclavicular line in the left 5th intercostal space. IE affecting these left-sided heart valves may cause septic embolization to the kidneys, brain, or other systemic organs but not to the pulmonary circulation. (Choice B) Pulmonic valve murmurs are best auscultated in the 2nd intercostal space at the left upper sternal border. IE affecting the pulmonic valve can occur in intravenous drug users and lead to septic pulmonary emboli, but it is far less common than tricuspid valve endocarditis. Educational objective: Infective endocarditis in intravenous drug users commonly affects the tricuspid valve, often leading to septic pulmonary emboli. Patients can have an early- or holo-systolic murmur of tricuspid regurgitation, which is best auscultated in the 4th or 5th intercostal space at the left lower sternal border.

A 33-Year-Old Man Comes to the Emergency Department Due to Fever