A 27-year-old man comes to the office due to 2 weeks of malaise, anorexia, and fatigue. The patient has had no cough, chest pain, arthralgias, or diarrhea. He underwent an uncomplicated dental root canal procedure 4 weeks ago. Medical history is otherwise unremarkable. Temperature is 38.5 C (101.3 F), blood pressure is 135/76 mm Hg, pulse is 90/min, and respirations are 18/min. His fingernail is shown in the image below: An early diastolic murmur is heard at the left sternal border. Chest x-ray is unremarkable. ECG reveals normal sinus rhythm. Urinalysis shows microscopic hematuria. Which of the following is the best next step in management of this patient?

Question

A 27-year-old man comes to the office due to 2 weeks of malaise, anorexia, and fatigue.  The patient has had no cough, chest pain, arthralgias, or diarrhea.  He underwent an uncomplicated dental root canal procedure 4 weeks ago.  Medical history is otherwise unremarkable.  Temperature is 38.5 C (101.3 F), blood pressure is 135/76 mm Hg, pulse is 90/min, and respirations are 18/min.  His fingernail is shown in the image below:  An early diastolic murmur is heard at the left sternal border.  Chest x-ray is unremarkable.  ECG reveals normal sinus rhythm.  Urinalysis shows microscopic hematuria.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d27a_c274_bc81_2799c379ec30_MD0003_00 Dental procedures are a common cause of transient bacteremia with viridans streptococci, a group of oral, commensal bacteria that are a leading cause of infective endocarditis (IE). Although risk is greatest with certain cardiac conditions (eg, prosthetic valves), healthy individuals with native valves occasionally develop IE following dental procedures. Most cases present with subacute nonspecific symptoms (eg, malaise, anorexia, fatigue) and several of the following: Fever Heart murmur Splinter hemorrhage (reddish brown lesion under nailbed) Petechiae Janeway lesions or Osler nodes Complications related to local cardiac infection (eg, heart failure) or to embolism (eg, brain) Laboratory evaluation often reveals an elevated erythrocyte sedimentation rate; hematuria may be present due to glomerulonephritis from septic emboli. The modified Duke criteria can help identify potential cases. modified Duke criteria Evaluation begins with blood cultures from 3 different venipuncture sites; this provides a microbiologic diagnosis in >90% of cases. Blood cultures should be drawn prior to initiating antibiotics to increase diagnostic yield (Choice E). Patients who are acutely ill or have a very high pretest probability of IE (as in this patient with a recent dental procedure, cardiac murmur, and several minor modified Duke criteria) are usually prescribed empiric antibiotics after blood cultures are drawn; in less ill individuals or those with a lower probability of IE, antibiotics are sometimes delayed until blood culture results return. Although transesophageal or transthoracic echocardiography is required to evaluate for vegetations and complications of cardiac infection (eg, perivalvular abscess), blood cultures should be done first so that antibiotics can be initiated while awaiting further testing (cardiac imaging often takes several hours to arrange) (Choices C and D). (Choice A) Antistreptolysin O titers help diagnose recent group A Streptococcus (GAS) infection (streptococcal pharyngitis) in patients with acute rheumatic fever. Although rheumatic fever can cause systemic symptoms and carditis (eg, murmur due to valvulitis), patients often have arthritis or arthralgias, with other manifestations including CNS involvement (eg, Sydenham chora) and subcutaneous nodules, not splinter hemorrhages or hematuria. Rheumatic fever typically develops weeks after an episode of GAS pharyngitis (not after a dental procedure). Educational objective: Patients with suspected infective endocarditis require blood cultures from 3 different venipuncture sites; this provides a microbial diagnosis in >90% of cases. Empiric antibiotics should not be administered prior to blood cultures because they reduce the ability to identify the causative pathogen. References: Infectious endocarditis: diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/22612050)

A 27-Year-Old Man Comes to the Office Due to 2