Introduction and Etiology of Endocarditis

Overview of Endocarditis

Endocarditis is a serious infection and inflammation of the inner lining of the heart chambers and valves, also known as the endocardium. It generally occurs when bacteria, fungi, or other microorganisms enter the bloodstream and subsequently attach to damaged areas of the heart. The condition can lead to severe complications if not promptly diagnosed and treated, including heart failure, stroke, and even death. This chapter provides an overview of endocarditis, its etiology, epidemiology, and the goals of treatment and management.

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Etiology and Classification

Endocarditis can be classified into two main categories: infective endocarditis (IE) and non-infective endocarditis.

• IE is the most common form and is caused by microorganisms, predominantly bacteria, such as Staphylococcus aureus, Streptococcus viridans, and Enterococcus species.
• Non-infective endocarditis, also known as marantic or Libman-Sacks endocarditis, is a rare form of the disease that is not caused by an infection and is usually associated with systemic lupus erythematosus or malignancies.

Risk factors for developing IE include having pre-existing heart valve abnormalities, a history of intravenous drug use, or a compromised immune system. Additionally, invasive medical procedures, such as dental work or the insertion of intravenous lines, can introduce microorganisms into the bloodstream, increasing the risk of endocarditis.

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Epidemiology and Global Burden

Endocarditis affects people of all ages and both sexes, but its incidence varies across different populations. The global incidence of IE is estimated to be between 3 and 10 cases per 100,000 person-years. The disease is more prevalent in developing countries due to limited access to healthcare and a higher prevalence of predisposing factors, such as rheumatic heart diseas. In developed countries, the incidence of IE has remained stable over the past few decades, but its demographic profile has shifted towards older adults with comorbidities and healthcare-associated infections.

The overall mortality rate of IE ranges from 15% to 25%, and the disease remains a significant cause of morbidity and mortality worldwide.

Early diagnosis and appropriate treatment are crucial in reducing the burden of endocarditis and improving patient outcomes.

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Goals of Treatment and Management

The primary goals of endocarditis treatment and management are to eradicate the causative microorganism, control the infection, and prevent complications. This is typically achieved through a combination of antimicrobial therapy, supportive care, and, in some cases, surgical intervention. Antibiotics are the mainstay of treatment for IE, and the choice of agent depends on the specific microorganism responsible for the infection, as well as the patient’s clinical condition and any existing comorbidities.

In addition to pharmacological treatment, the management of endocarditis may involve monitoring for complications and addressing any underlying risk factors. Surgical intervention may be necessary in cases of severe valve damage, persistent infection despite appropriate antibiotic therapy, or the development of life-threatening complications, such as heart failure or embolic events.