A 33-year-old man comes to the emergency department due to 3 days of shortness of breath, profound fatigue, and chills. The patient has a history of intravenous drug use. He was enrolled in a methadone program but admits to relapsing last week. Temperature is 40 C (104 F), blood pressure is 75/40 mm Hg, pulse is 122/min and regular, and respirations are 40/min. He is admitted to the intensive care unit but dies despite treatment efforts. Lung autopsy findings are shown in the image below. Which of the following is the most likely diagnosis in this patient?

Question

A 33-year-old man comes to the emergency department due to 3 days of shortness of breath, profound fatigue, and chills.  The patient has a history of intravenous drug use.  He was enrolled in a methadone program but admits to relapsing last week.  Temperature is 40 C (104 F), blood pressure is 75/40 mm Hg, pulse is 122/min and regular, and respirations are 40/min.  He is admitted to the intensive care unit but dies despite treatment efforts.  Lung autopsy findings are shown in the image below.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec160b_3a1a_aa4a_9249_e3977e12cc47_MD0001_00 The lung specimen above shows multiple wedge-shaped hemorrhagic infarcts in the periphery of the lung, which, given this patient's presentation, are most likely due to septic pulmonary emboli. Patients with intravenous drug use are at increased risk of developing tricuspid valve endocarditis, most commonly due to Staphylococcus aureus. The clinical presentation is typically acute with high-grade fever, and tachycardia and hypotension due to septic shock. The majority of patients with tricuspid valve endocarditis experience embolization of tricuspid valve vegetation fragments; these fragments lodge in distal portions of the pulmonary arterial tree and cause septic pulmonary infarcts. The infarcts are typically wedge-shaped due to the triangular perfusion field of small arteries at the lung periphery. Due to the relatively low density of lung tissue (which allows blood seepage into tissue during infarction) and a dual blood supply (ie, pulmonary and bronchial arteries), pulmonary infarcts are typically hemorrhagic (red) rather than ischemic (white). (Choice A) Miliary tuberculosis typically has a subacute or chronic presentation and is accompanied by night sweats, weight loss, and anorexia. Innumerable, small, white nodules resembling millet seeds are typically seen; peripherally located wedge-shaped hemorrhages in the lung are not characteristic. (Choice B) Mycotic aneurysms may occur as a complication of endocarditis; however, they refer to the local destruction and dilation of an arterial wall due to infection. Despite their name, mycotic aneurysms are very rarely associated with fungal infections. (Choice C) Small airway obstruction is characteristic of asthma, which typically presents with dyspnea, cough, wheezing, and chest tightness. Lung autopsy usually reveals the occlusion of bronchi and bronchioles by thick mucous plugs containing shed epithelium. (Choice E) Venous thromboembolism in the pulmonary vasculature (ie, thrombotic pulmonary embolism) can also cause wedge-shaped hemorrhagic infarct in the periphery of the lung. However, this patient's high-grade fever and recent intravenous drug use are more suggestive of septic emboli from tricuspid valve endocarditis. In addition, multiple pulmonary infarcts are more consistent with septic embolization than venous thromboembolism. Educational objective: Pulmonary infarcts are typically hemorrhagic (red) and wedge-shaped in the periphery of the lung. Intravenous drug users are at increased risk of tricuspid valve endocarditis, which can cause multiple septic pulmonary infarcts due to embolization of tricuspid valve vegetation fragments. __________ References: Tricuspid valve endocarditis with septic pulmonary emboli in a drug addict. (http://www.ncbi.nlm.nih.gov/pubmed/22446954)

A 33-Year-Old Man Comes to the Emergency Department Due to 3