Continuing Medical Education
An approach to a patient with infective endocarditis
Abstract
Although infective endocarditis (IE) is relatively uncommon, it remains an important clinical entity with a high in-hospital and 1-year
mortality. It is most commonly caused by viridans streptococci. Staphylococcus aureus is responsible for a malignant course of IE and
often requires early surgery to eradicate. Other rarer causes are various bacilli, including the HACEK (Haemophilus, Actinobacillus,
Cardiobacterium, Eikenella and Kingella spp.) group of organisms and fungi. The clinical presentation varies. Patients may present with
a nonspecific illness, valve dysfunction, heart failure (HF) and symptoms due to peripheral embolisation. The diagnosis is traditionally
based on the modified Duke criteria and rests mainly on clinical features and to a lesser extent on certain laboratory findings,
microbiological assessment and cardiovascular imaging. Identification of the offending micro-organism is not only important from a
diagnostic point of view, but also makes targeted antibiotic treatment possible and provides useful prognostic information. A significant
proportion of microbiological cultures are negative, frequently owing to the administration of antibiotics prior to appropriate culture.
Blood-culture-negative IE poses significant diagnostic and treatment challenges. The course of the disease is frequently complicated, and
sequelae include HF, local intracardiac extension of infection (abscess, fistula, pseudoaneurysm), stroke and intracranial haemorrhage
due to septic emboli or mycotic aneurysm formation as well as renal injury. Management includes prolonged intravenous antibiotics and
consideration for early surgery with removal of infective tissue and valve replacement in patients who have poor prognostic features or
complications. Antibiotic administration for at-risk patients to prevent bacteraemia during specific procedures (particularly dental) is
recommended to prevent IE. The patient population who would benefit from antibiotic prophylaxis has become increasingly restricted,
and guidelines recommend prophylaxis only for patients with cyanotic congenital heart disease, prosthetic heart valves and a previous
episode of IE. The management of a patient with IE is challenging and often requires multidisciplinary input from an IE heart team,
which includes cardiologists.
Authors' affiliations
Jens Hitzeroth, Private Practice, Vincent Pallotti Hospital, Cape Town, South Africa
Nazlea Beckett, Division of Family Medicine, School of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town, South Africa
Patrick Ntuli, Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, and Groote Schuur Hospital, Cape Town, South Africa
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Date published: 2015-11-26
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