So Bored, I Began to Murmur – Duke Criteria for Infective Endocarditis

An unknown young male makes his way into the critical care area of your emergency department on a boring night. He is minimally responsive and is breathing at a very slow rate. You look at his pupils, and they are pinpoint. You see track marks up and down his arms. You already anticipate on clearing him for evaluation in the main area after giving him a whiff of naloxone, but as your nurses hook him up to the monitor and get that ever-important rectal temperature, you see a reading of 103F. He is “flagged for sepsis”.

 

After some naloxone, the patient wakes up and identifies himself as Duke. He admits that he’s been shooting heroin and maybe went a little overboard tonight primarily because he’s been feeling so ill over the past few weeks. He endorses subjective fevers, dyspnea, and a weird rash, but otherwise denies headache, neck pain, cough, vomiting, abdominal pain, or dysuria. You send sepsis labs. Unfortunately, he doesn’t offer a clear history that would key you into the source of his fever. Results of the workup start to trickle in. He has a leukocytosis. The chest X-ray is clear. The urine is clean. Blood cultures are pending. You go back to your trusty old physical exam and bedside tools to try to put it all together. He is febrile, tachycardic, and borderline hypotensive. He has some odd skin lesions on his hands and feet, but they aren’t your run-of-the-mill cellulitis or abscess. You also hear a faint systolic murmur. As an astute resident, you decide to run through a RUSH (Rapid Ultrasound for Shock and Hypotension) exam and find this on your apical 4 view.

 

How do we use the history, exam, lab, and radiologic findings to diagnose infective endocarditis (“IE”)?

Duke Clinical Criteria for the Diagnosis of Infective Endocarditis

 

What are the components of the Duke Criteria?

  1. Major Criteria
    • Positive blood culture for IE
      • Typical microorganism consistent with IE from 2 separate blood cultures, including the following: viridans streptococci, Streptococcus bovis, or HACEK group, or community-acquired Staphylococcus aureus or enterococci in the absence of a primary focus
      • Microorganisms consistent with IE from persistently positive blood cultures defined as: 2 positive cultures of blood samples drawn >12 hours apart or all of 3 or a majority of 4 separate blood cultures
    • Positive echocardiogram for IE
      • Oscillating intracardiac mass on valve, abscess, or new partial dehiscence of prosthetic valve
      • Sensitivity of TTE is highest in IVDU (88% to 94%) who more often have larger vegetations, a preponderance of right-sided lesions, and patients are younger with a favorable acoustic precordial window.
    • New valvular regurgitation
  1. Minor Criteria
    • Predisposition: Prior heart condition or injection drug use
    • Fever: Temperature >38°C (100.4°F)
    • Vascular phenomena: Major arterial emboli, septic pulmonary conjunctival hemorrhages, or Janeway lesions
    • Immunologic phenomena: Glomerulonephritis, Osler nodes, Roth spots, or rheumatoid fever
    • Microbiologic evidence: Positive blood culture but does not meet a major criterion or serologic evidence of active infection with organism consistent with IE

 

How do we use the Duke Criteria to diagnose IE?

  1. Definite IE
    • 2 major criteria
    • 1 major and 3 minor criteria
    • 5 minor criteria
  2. Possible IE
    • Findings consistent with IE that fall short of “definite” but are not “rejected”
  3. Rejected IE (1 of these)
    • Firm alternate diagnosis for manifestations of endocarditis
    • Resolution of manifestations of endocarditis with antibiotic therapy for 4 days or less
    • No pathologic evidence of IE at surgery or autopsy after antibiotic therapy for ≤ 4 days

 

What are the unique physical exam findings included in the Duke Criteria for IE?

1) Heart murmur

2) Janeway Lesions: Painless macules located on the thenar and hypothenar eminences of the hands and feet. Pathologically, these lesions are microabscesses of the dermis caused by septic emboli.

 

3) Osler Nodes: Small, tender nodules that range from red to purple and are in the pulp spaces of the terminal phalanges of the fingers and toes, the soles of the feet, and the thenar and hypothenar eminences of the hands.

 

4) Roth Spots: Oval-shaped hemorrhages with white centers present on the retina.

 

5) Splinter Hemorrhages: Red lines of blood running under the nails in the direction of nail growth that look like splinters and may be caused by vasculitis or microemboli.


How good are the Duke Criteria?

  • The Duke criteria have a sensitivity of about 80%
  • Validation studies of the Duke criteria have found a specificity of 99% and a negative predictive value of 92%, giving them good diagnostic power.

 

Back to the case...

Our patient is a young IVDU presenting with fever, heart murmur, and rash. Transthoracic echocardiogram showed vegetations on the tricuspid valve. He meets 1 major and 3 minor Duke criteria which suggests definite IE. Although the blood cultures are pending, Vancomycin, nafcillin, and gentamicin are started in the ED, and he is admitted to medicine with a presumptive diagnosis of IE. A transesophageal echocardiogram confirms the ED findings, and blood cultures grow MRSA. The patient has a PICC line placed and receives antibiotics for 6 weeks.

 

Sources

Clarke, Michelle. “Emergency Department Management of Acute Infective Endocarditis.” EB Medicine, Nov. 2014, Volume 16, Number 11. http://www.ebmedicine.net/topics.php?paction=showTopic&topic_id=423. Accessed 29 April 2017.

Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology. 7th ed. New York: McGraw-Hill, 2013. Copyright © 2013 by The McGraw-Hill Companies, Inc.

Rothman R, Marco CA, Yang S. Endocarditis. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e New York, NY: McGraw-Hill; 2016. http://accessmedicine.mhmedical.com.newproxy.downstate.edu/content.aspx?bookid=1658&sectionid=109412986. Accessed April 01, 2017.

 

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Derick

PGY-1 Emergency Medicine Resident at SUNY Downstate Medical Center/King's County Hospital Center
Clinical Monster in Training @DrAlfonsoEM

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