A 54-year-old man comes to the emergency department due to several hours of left upper quadrant pain, which is constant and worsens with deep inspiration. The patient came to the emergency department a week ago due to fatigue and low-grade fevers for the past month. Blood cell counts, chest x-ray, and urinalysis were within normal limits, and the patient was discharged home with symptomatic treatment. He has had no cough, shortness of breath, vomiting, or diarrhea but reports a 4.5-kg (10-lb) weight loss over the past month. Medical history includes hypertension, osteoarthritis, and a "heart murmur." The patient is a smoker with a 30-pack-year history, drinks alcohol occasionally, and does not use illicit drugs. He is a livestock farmer in rural Pennsylvania and recently returned from a hunting trip.
Temperature is 38.4 C (101.1 F), blood pressure is 136/72 mm Hg, pulse is 90/min, and respirations are 16/min. The lungs are clear on auscultation. Heart sounds are normal, and a 2/6 early diastolic murmur is present at the right upper sternal border. The abdomen is tender in the left upper quadrant with no guarding or rebound tenderness.
Laboratory results are as follows:
ECG shows sinus rhythm with nonspecific ST- and T-wave changes. CT scan of the abdomen reveals multiple splenic infarcts. Three sets of blood cultures obtained during the previous emergency department visit reveal no growth. Which of the following is the best next step in management of this patient?

Question

A 54-year-old man comes to the emergency department due to several hours of left upper quadrant pain, which is constant and worsens with deep inspiration.  The patient came to the emergency department a week ago due to fatigue and low-grade fevers for the past month.  Blood cell counts, chest x-ray, and urinalysis were within normal limits, and the patient was discharged home with symptomatic treatment.  He has had no cough, shortness of breath, vomiting, or diarrhea but reports a 4.5-kg (10-lb) weight loss over the past month.  Medical history includes hypertension, osteoarthritis, and a "heart murmur."  The patient is a smoker with a 30-pack-year history, drinks alcohol occasionally, and does not use illicit drugs.  He is a livestock farmer in rural Pennsylvania and recently returned from a hunting trip.
Temperature is 38.4 C (101.1 F), blood pressure is 136/72 mm Hg, pulse is 90/min, and respirations are 16/min.  The lungs are clear on auscultation.  Heart sounds are normal, and a 2/6 early diastolic murmur is present at the right upper sternal border.  The abdomen is tender in the left upper quadrant with no guarding or rebound tenderness.
Laboratory results are as follows:
 ECG shows sinus rhythm with nonspecific ST- and T-wave changes.  CT scan of the abdomen reveals multiple splenic infarcts.  Three sets of blood cultures obtained during the previous emergency department visit reveal no growth.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_95e8_018b_853d_711ae06df352_MD0002_00 This patient has multiple findings to suggest subacute infective endocarditis (ie, fatigue, low-grade fevers, splenic infarcts, murmur of aortic regurgitation). No growth on 3 sets of blood cultures after ≥7 days is consistent with culture-negative endocarditis (CNE), which suggests fungi or fastidious bacteria (eg, Coxiella burnetii, Bartonella spp, Tropheryma whippelii) as the most likely organism. HACEK bacteria are relatively easily detected by modern culture methods and are no longer considered a common cause of CNE. HACEK In a large epidemiologic study of CNE, C burnetii was the most common organism identified; it is typically contracted by droplet exposure from infected livestock. Acute infection manifests as Q fever, which typically consists of pneumonia with flu-like symptoms and hepatitis but can be asymptomatic. Infective endocarditis can occur several months following acute infection; it is seen primarily in men age >40, pregnant women, and patients with underlying valvular pathology. The modified Duke criteria are used for diagnosis; positive Q fever serology (IgG antibody titer >1:800) is considered a major clinical criterion. Initial diagnostic evaluation should include transthoracic or transesophageal echocardiography to identify valvular vegetations and perivalvular lesions. Positron emission tomography may also be helpful in suggesting infectious valvular pathology. modified Duke criteria (Choices A and D) Systemic lupus erythematosus and malignancy are potential causes of nonbacterial thrombotic endocarditis (valvular deposition of sterile platelet thrombi). However, fever and a heart murmur are uncommon in nonbacterial thrombotic endocarditis, and systemic embolization (eg, stroke) is the more typical initial presentation. (Choice B) Intracytoplasmic inclusions (morulae) are seen in ehrlichiosis, a tick-borne illness common in the southeastern and mid-Atlantic United States. Patients typically have fever accompanied by fatigue, arthralgias, headaches, and splenomegaly. However, leukopenia and thrombocytopenia are typically present, making the diagnosis less likely in this patient. (Choice E) Inherited thrombophilia (eg, factor V Leiden, protein C or S deficiency) may cause splenic infarction, often with associated fever. However, this patient has been having fevers for a month, and an inherited thrombophilia would not explain a regurgitant murmur. Educational objective: Coxiella burnetii causes Q fever and is one of the most common causes of culture-negative endocarditis. The initial evaluation of patients with suspected Q-fever endocarditis should include transthoracic or transesophageal echocardiography to identify valvular vegetations. __________ References: Comprehensive diagnostic strategy for blood culture-negative endocarditis: a prospective study of 819 new cases. (http://www.ncbi.nlm.nih.gov/pubmed/20540619) Infective endocarditis in adults: diagnosis, antimicrobial therapy, and management of complications: a scientific statement for healthcare professionals from the American Heart Association. (http://www.ncbi.nlm.nih.gov/pubmed/26373316)

A 54-Year-Old Man Comes to the Emergency Department Due to Several