A Barely Responsive Woman Dropped at the ED With a Note

Gregory Taylor, DO; Eric McDowell, DO

Disclosures

November 05, 2020

A diagnosis of infective endocarditis should be considered in any patient with fever and recognized risk factors. Cardiac risk factors include prior infective endocarditis, a prosthetic heart valve, or history of valvular disease (eg, congenital heart disease). Noncardiac risk factors include IV drug abuse, indwelling IV lines, and recent dental or surgical procedure.[5] In general, the diagnosis is established on the basis of clinical manifestations, blood cultures, echocardiography, and the Duke criteria. Echocardiography should be performed in all patients with suspected infective endocarditis. Transthoracic echocardiography should be the first diagnostic test; however, transesophageal echocardiography has a higher sensitivity and is better at detecting cardiac complications and prosthetic valve endocarditis.[5]

The Duke criteria are used by clinicians to diagnose infective endocarditis. Major criteria include positive blood cultures from two separate blood collections and evidence of endocardial involvement (as noted on an echocardiogram) in the form of a vegetation, abscess, or a new valvular regurgitation. The minor criteria include a history of IV drug abuse, fever, vascular phenomena (eg, major arterial emboli, septic pulmonary infarcts, Janeway lesions), and immunologic phenomena (eg, Roth spots, Osler nodes, glomerulonephritis). Diagnosis requires two major criteria, one major criterion and three minor criteria, or five minor criteria.

The patient in this case had two positive blood cultures for S aureus . She also demonstrated an obvious holosystolic murmur; because prior findings could not be accessed, determining whether this finding had newly developed was impossible, and she died before echocardiography could be performed. This patient had an extensive history of IV drug abuse, with multiple track marks throughout her body, and lesions on her palms consistent with Janeway lesions, along with hypothermia. All findings were consistent with a diagnosis of infective endocarditis.

Right-sided endocarditis is particularly common among IV drug abusers secondary to a nonsterile injection within the venous system.[2] The injected drugs (eg, heroin, cocaine) tend to cause vasospasm, damage to the intima, and resulting thrombus formation, which then predisposes to bacterial aggregation.[6] Right-sided endocarditis differs from classic infective endocarditis in that these patients are more likely to develop septic pulmonary emboli and pneumonia, compared with the characteristic signs mentioned above, which occur secondary to left-sided endocarditis.[6] The tricuspid valve is affected about 50% of the time, whereas mitral and aortic valves are affected about 20% of the time; however, multiple valves are commonly affected.[2]

The patient in this case demonstrated clinical signs consistent with likely multiple valve involvement, as well as evidence of both peripheral signs and multifocal pneumonia. The proportion of infective endocarditis cases that involve the tricuspid valve in IV drug abusers ranges from 30% to 70%.[4] In one autopsy series involving 80 patients with IV drug abuse and endocarditis, isolated tricuspid valve involvement was found in about 30% of cases, mitral valve or aortic valve involvement was found in about 40%, and both right- and left-sided involvement was found in about 16%.[4]

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