A 42-year-old man comes to the office due to 4 weeks of fatigue and weakness. He has also had fleeting joint pains, low-grade fever, dark and cloudy urine, pain in the fingertips, and shortness of breath when walking fast or climbing stairs. Examination shows tender, subcutaneous, violaceous nodules on the pads of the fingers. Laboratory results are as follows: Urinalysis shows 2+ blood and 1+ protein. Which of the following is the best step in establishing a diagnosis in this patient?

Question

A 42-year-old man comes to the office due to 4 weeks of fatigue and weakness.  He has also had fleeting joint pains, low-grade fever, dark and cloudy urine, pain in the fingertips, and shortness of breath when walking fast or climbing stairs.  Examination shows tender, subcutaneous, violaceous nodules on the pads of the fingers.  Laboratory results are as follows:  Urinalysis shows 2+ blood and 1+ protein.  Which of the following is the best step in establishing a diagnosis in this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d44e_e62b_bc81_7bd79bc3036e_MD0003_00 This patient's subacute nonspecific symptoms, low-grade fever, and elevated erythrocyte sedimentation rate indicate a systemic inflammatory process such as a smoldering infection or rheumatic disease. Although arthralgias and glomerulonephritis (eg, hematuria, proteinuria, dark and cloudy urine) can be seen in rheumatic conditions, the presence of these manifestations plus subcutaneous, violaceous nodules on the fingers (Osler nodes) is highly suggestive of infective endocarditis (IE). Patients with IE often have days or weeks of nonspecific systemic symptoms (eg, fever, weight loss, myalgia, arthralgia, malaise) and manifestations related to the following: Direct cardiac injury: valvular insufficiency and heart failure (eg, dyspnea, cough, edema) Immunologic response: immune complex-mediated glomerulonephritis (hematuria, red cell casts) or skin manifestations (eg, Osler nodes) Infectious metastasis: septic emboli (eg, brain, vertebral body, spleen, lung) or mycotic aneurysm Laboratory studies typically show normocytic anemia (eg, anemia of chronic disease) and elevated erythrocyte sedimentation rate (ESR). The modified Duke criteria helps confirm the diagnosis; 3 sets of blood cultures should be obtained to identify the causative microbe, and an echocardiography should be performed to assess valve function and evaluate for vegetations or complications (eg, perivalvular abscess). modified Duke criteria (Choice B) Parvovirus B19 can cause a transient viral illness with nonspecific flu-like symptoms (eg, malaise, myalgia, fever), arthralgia, and/or rash (eg, circumoral pallor, reticulated/lace-like). However, Osler nodes, active urine sediment, and several weeks of symptoms would be atypical. (Choice C) Antistreptolysin titer helps diagnose poststreptococcal glomerulonephritis, which is associated with active urine sediment and dark urine. However, cases are typically preceded by a sore throat or skin infection; arthralgias and Osler nodes would be atypical. (Choice D) Adult Still disease often causes significant elevation in ferritin level as part of the systemic inflammatory response. Although arthralgias and elevated ESR are common, most patients have high fever and a salmon-colored macular or maculopapular rash. Active urine sediment and Osler nodes would be atypical. rash (Choice E) Rheumatoid arthritis can cause low-grade fever, fatigue, and elevated ESR. However, multijoint pain, stiffness, and swelling are usually prominent. In addition, Osler nodes and active urine sediment would be atypical. Some patients with IE have positive rheumatoid factor, which is thought to be an immunologic phenomenon of infection. Educational objective: Infective endocarditis usually presents with subacute nonspecific (eg, fever, fatigue, myalgia, arthralgia), cardiac (eg, dyspnea), immunologic (eg, glomerulonephritis, Osler node), and/or embolic symptoms. Diagnosis is typically confirmed with 3 sets of blood cultures and echocardiogram.

A 42-Year-Old Man Comes to the Office Due to 4