Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.
A 46-year-old woman is evaluated before undergoing a dental cleaning procedure involving deep scaling. She has a history of mitral valve prolapse without regurgitation and also had methicillin-resistant Staphylococcus aureus (MRSA) aortic valve endocarditis 10 years ago treated successfully with antibiotics. The patient notes an allergy to penicillin characterized by hypotension, hives, and wheezing. The remainder of the history is noncontributory.
On physical examination, vital signs are normal. Cardiopulmonary examination discloses a late systolic click. The remainder of the examination is normal.
Which of the following is the most appropriate prophylactic regimen for this patient before her dental procedure?
A: Amoxicillin
B: Cephalexin
C: Clindamycin
D: Vancomycin
E: No prophylaxis
MKSAP Answer and Critique
The correct answer is C: Clindamycin. This item is available to MKSAP 16 subscribers as item 78 in the Infectious Disease section.
This patient with a history of infective endocarditis requires antimicrobial prophylaxis with clindamycin before her dental procedure. The American Heart Association (AHA) infective endocarditis guidelines, revised in 2007, now recommend that only patients with cardiac conditions associated with the highest risk of adverse outcome from endocarditis receive antimicrobial prophylaxis before undergoing a dental procedure involving manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. These conditions include the presence of a prosthetic cardiac valve, history of infective endocarditis, unrepaired cyanotic congenital heart disease, congenital heart disease repair with prosthetic material or device for the first 6 months after intervention, presence of palliative shunts and conduits, and cardiac valvulopathy in cardiac transplant recipients. The suggested antibiotic prophylactic regimens before dental procedures for patients with these indications are agents directed against viridans group streptococci, administered as a single dose 30 to 60 minutes before the procedure. Clindamycin, azithromycin, or clarithromycin would be appropriate choices for this patient, who experienced anaphylaxis after receiving penicillin.
Amoxicillin and cephalosporins such as cephalexin should not be used in patients with a history of anaphylaxis after receiving penicillin.
Vancomycin is not required because, despite this patient’s history of methicillin-resistant Staphylococcus aureus endocarditis, this previous infection does not influence the antibiotic choice for prophylactic endocarditis treatment.
According to the AHA guidelines, a history of infective endocarditis is one of the indications for infective endocarditis prophylaxis before a dental procedure involving gingival manipulation; consequently, providing no prophylaxis to this patient would not be appropriate.
Key Point
- The indications for infective endocarditis antimicrobial prophylaxis for patients who will undergo a dental procedure involving manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa are (1) the presence of a prosthetic cardiac valve, (2) a history of infective endocarditis, (3) unrepaired cyanotic congenital heart disease, (4) congenital heart disease repair with prosthetic material or device for the first 6 months after intervention, (5) presence of palliative shunts and conduits, and (6) cardiac valvulopathy in cardiac transplant recipients.
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