**Abstract**

Intravenous drug use is associated with infective endocarditis. Besides, it does appear that left-sided infective endocarditis is a feature of general population, whereas right-sided infective endocarditis is common in intravenous drug users. The most common etiology of right-sided infective endocarditis in intravenous drug users is *Staphylococcus aureus* in about 75% followed by streptococci, Gramnegative bacilli and fungi. In case of intravenous drug users with infective endocarditis, optimal treatment strategies lack a general consensus. Additionally, the best indication and timing of surgery are debatable. To overcome these problems, the early and complete surgical debridement of infected tissue together with microbial therapy assures a good prognosis in the long term.

**Keywords:** endocarditis, drug-associated endocarditis, intravenous drug abuser endocarditis, intravenous drug users, right heart endocarditis

#### **1. Introduction**

 Infective endocarditis (IE) is a rare infectious disease with elevated morbidity and mortality [1]. Intravenous drug use is associated with infective endocarditis (IE) [2]. To the best of our knowledge, IE accounts for 2–5% per year among the intravenous drug users (IDUs) [3–6]. Approximately 41% of IDUs with bacteremia will develop IE [7]. Conversely, it is widely agreed that intravenous drug users (IDUs) diagnosed with IE are mainly white young males [8–12].

Right-sided infective endocarditis has been mainly defined among IDUs [13–15]. Generally, right-sided IE comprises 5–10% of cases with IE [16–18]. It does appear that left-sided IE is a feature of general population, whereas right-sided IE is common in IDUs [19–21]. To further characterize, IDUs may present in 86% cases right-sided IE, whereas 14% have left-sided IE with or without right-sided IE [21]. However, some older data outlines that the IDUs group may present equal incidence of left-sided and right-sided IE [22].

Common *predisposing factors* for right-sided IE are the intravenous drug users (IDUs), catheter-related infections, pacemaker or defibrillators wires, intracardiac devices (catheters for hemodialysis; tricuspid prosthetic valve), right heart catheterization, congenital heart defects, sepsis, and alcoholism [13–15, 23]. In case of

the right-sided IE, tricuspid valve is affected in 90% cases [21], whereas pulmonic valve represents about 10% from right-sided IE cases [3, 18, 24]. Up to now, isolated right-sided IE involving the pulmonary valve, the eustachian valve, interventricular septum, or right ventricular free wall have been described [17, 21, 25].
