Photo Quiz

Nontender Rash on the Soles of the Feet in a Febrile Adult


Am Fam Physician. 2021 Jul ;104(1):83-84.

A 63-year-old patient with multiple chronic medical conditions was admitted to the hospital for nonpurulent cellulitis at the base of the neck. The diagnostic workup revealed methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and a urinary tract infection. Chest radiography and transthoracic echocardiography were unremarkable.

After five days of appropriate culture-guided intravenous antibiotics, the patient's inflammatory markers remained elevated, and blood cultures continued to grow MRSA. Skin examination revealed lesions on the soles of the feet (Figure 1).




Based on the patient's history and physical examination findings, which one of the following is the best next step?

  • A. Biopsy of foot lesions.

  • B. Referral for cardiothoracic surgery.

  • C. Repeat transthoracic echocardiography.

  • D. Rickettsia serology.

  • E. Transesophageal echocardiography.


The answer is E: transesophageal echocardiography. Figure 1 shows Janeway lesions caused by septic microthrombi, which are highly suggestive of infective endocarditis. When there is low suspicion for endocarditis, the American Heart Association recommends beginning with transthoracic echocardiography.1 If concerning features are found or suspicion for infective endocarditis increases, a transesophageal echocardiography should be performed. Transesophageal echocardiography detects evidence of infective endocarditis in 19% of patients with negative findings on transthoracic echocardiography and allows for further characterization of valvular disease and evaluation for surgical management.2

Infective endocarditis affects 0.011% to 0.015% of the U.S. population.3 Risk factors include older age, structural heart or valvular disease, injection drug use, poor dentition, dental infection, HIV, and long-term dialysis.4 S. aureus is the most common causative organism.5

Suspicion for infective endocarditis is initially evaluated using modified Duke criteria (Table 1).2 Infective endocarditis can be definitively diagnosed if the patient has two major criteria, one major and three minor criteria, or five minor criteria. Infective endocarditis is possible in those with one major and one minor criteria or three minor criteria. A definite diagnosis according to modified Duke criteria has a sensitivity of 80%.2 A nondiagnosis has a negative predictive value of more than 92%.2 This patient had one major and one minor criteria initially, developing a second minor criterion with the septic emboli. The patient underwent a transesophageal echocardiography, which revealed endocardial involvement. This provided the two major criteria needed for a definitive diagnosis.

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Modified Duke Criteria for Diagnosing Infective Endocarditis

Major criteria

Two positive blood cultures for organisms known to commonly cause infective endocarditis

Single culture positive for Coxiella burnetii

Endocardial involvement

Address correspondence to Samuel Tiglao, DO, at Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.


show all references

1. Baddour LM, Wilson WR, Bayer AS, et al. Infective endocarditis in adults: diagnosis, antimicrobial therapy, and management of complications: a scientific statement for healthcare professionals from the American Heart Association [published correction appears in Circulation. 2015;132(17):e215, Circulation. 2016;134(8):e113, and Circulation. 2018;138(5):e78–e79]. Circulation. 2015;132(15):1435–1486....

2. Li JS, Sexton DJ, Mick N, et al. Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis. Clin Infect Dis. 2000;30(4):633–638.

3. Pant S, Patel NJ, Deshmukh A, et al. Trends in infective endocarditis incidence, microbiology, and valve replacement in the United States from 2000 to 2011. J Am Coll Cardiol. 2015;65(19):2070–2076.

4. Hill EE, Herijgers P, Claus P, et al. Infective endocarditis: changing epidemiology and predictors of 6-month mortality: a prospective cohort study. Eur Heart J. 2007;28(2):196–203.

5. Murdoch DR, Corey GR, Hoen B, et al. Clinical presentation, etiology, and outcome of infective endocarditis in the 21st century: the International Collaboration on Endocarditis-Prospective Cohort Study. Arch Intern Med. 2009;169(5):463–473.

6. Horino T, Hori S. Metastatic infection during Staphylococcus aureus bacteremia. J Infect Chemother. 2020;26(2):162–169.

7. Bin Abdulhak AA, Tleyjeh IM. Indications of surgery in infective endocarditis. Curr Infect Dis Rep. 2017;19(3):10.

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

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