19th June 2024

Infective endocarditis

Background

Infective endocarditis (IE) can present with various clinical features, depending on intracardiac pathology, evolution of the infection and possible extra-cardiac involvement. In general, a fever and a new murmur indicate endocarditis until proven otherwise.

Clinical presentation

General features of infection include malaise, anorexia, weight loss and night sweats. Anaemia, clubbing and splenomegaly can occur in long standing infections. Cardiac manifestations of infection include congestive cardiac failure, palpitations, tachycardia, a new murmur and AV block.

In addition, patients may present with haemorrhagic manifestations. For instance, on the skin you may see petechiae, splinter haemorrhages, and small tender nodules on palms and soles of feet; pulp infarcts known as Osler’s nodes.

In the eye, you may see oval shaped retinal haemorrhages with a pale centre located near the optic disc, these are known as Roth spots. Conjunctival splinter haemorrhages and retinal flame haemorrhages may also be seen.

In the kidney, microscopic haematuria may be seen, with glomerulonephritis as a result of immune complex deposition. Cerebrally, you may also have toxic encephalopathy.

Diagnosis & Treatment

2 Major or 1 Major and 3 Minor criteria are required, or all 5 minor criteria are required.

Medical treatment is based on the sensitivity of organisms isolated, with broad spectrum antibiotics used in the initial blind therapy when infective endocarditis is suspected. Surgery also plays a significant role in the management of IE, this will be teased out in the following questions.

Prophylaxis

Antibiotic Prophylaxis for IE is suggested only in the setting of conditions associated with the highest risk of an adverse outcome if IE occurs. For instance, patients with prosthetic valves or valve repairs using devices such as annuloplasty, rings or clips should have prophylaxis. In addition, those with left ventricular assist devices or previous or recurrent IE should also have prophylaxis.

In patients with a history of congenital heart disease, it can become more complex. Prophylaxis is indicated in those with unrepaired cyanotic heart disease and those with defects that have been fully or partially fixed with prosthetic materials.

References

• Chu VH, Calderwood SB, Baron EL. Native valve endocarditis: Epidemiology, risk factors, and microbiology. In UpToDate, Calderwood SB (Ed), UpToDate, Waltham, MA. (Accessed May 2022)
• Ramrakha PS, Moore KP, Sam A. Oxford Handbook of Acute Medicine (3rd ed.). Oxford (UK): Oxford University Press; 2010
• Wilkinson IE, Raine T, Wiles K, Goodhart A, Hall C, O’Neill H. Oxford Handbook of Clinical Medicine (10th ed.). Oxford (UK): Oxford University Press; 2017
• Karchmer AF, Calderwood SB, Baron EL. Prosthetic valve endocarditis: Epidemiology, clinical manifestations, and diagnosis. In UpToDate, Calderwood SB (Ed), UpToDate, Waltham, MA. (Accessed May 2022)
• Wang A, Bolger A, Yeon SB. Overview of management of infective endocarditis in adults. In UpToDate, Calderwood SB (Ed), UpToDate, Waltham, MA. (Accessed May 2022)
• Sexton DJ, Calderwood SB, Baron EL. Right-sided native valve infective endocarditis. In UpToDate, Calderwood SB (Ed), UpToDate, Waltham, MA. (Accessed May 2022)
• Sexton DJ, Otto CM, Baron EL. Antimicrobial prophylaxis for the prevention of bacterial endocarditis. In UpToDate, Calderwood SB (Ed), UpToDate, Waltham, MA. (Accessed May 2022)