Right-Sided Endocarditis in a Diabetic Patient

High-grade fever, chills, fatigue, malaise, and anorexia developed in a 35-year-old man following subclavian catheterization because of chronic renal failure of unknown cause.

The patient, who had long-standing diabetes mellitus, was admitted to the ICU with the diagnosis of possible sepsis. The next day, he was found to have a grade 2/6 systolic murmur compatible with tricuspid regurgitation.

This was confirmed when a 4-chamber echocardiogram (A) revealed a large single piece of vegetation (2 arrows) lying on the tricuspid valve, flapping in and out of the right ventricle.

In a 2-dimensional echocardiogram of the right atrium and right ventricle (B), 3 arrows point to the vegetation. (RV, right ventricle; LV, left ventricle; RA, right atrium; LA, left atrium; TV, tricuspid valve.) The results of 3 sets of blood cultures were positive for Staphylococcus aureus, and the patient was given intravenous vancomycin for 6 weeks. This therapy failed, and he then underwent tricuspid valve replacement.

The postoperative course did not go well, and the patient died. Infective endocarditis is virtually always fatal unless the patient receives treatment. A right-sided infective endocarditis is rare unless the patient has a history of drug abuse. In this patient, diabetes and renal failure may have contributed to the occurrence of sepsis; diabetes has been associated with infective endocarditis in 15% of cases.¹

Although it has not been directly documented, metabolic, immunologic, and vascular abnormalities in diabetic patients may significantly contribute to their susceptibility to endocarditis.² Moreover, these patients are increasingly prone to any type of infection—first, because of poor perfusion, and second, because acidosis inhibits leukocytic migration and phagocytosis.

Both conditions can serve as sources of bacteremia.³ In addition, an increased incidence of S aureus colonization on the skin and nares has been documented in diabetic patients.⁴