Right-Sided Infectious Endocarditis in the Patient With Williams Syndrome: Importance of Recognizing Disease-Specific Pathophysiology in Adults.

Infectious endocarditis (IE) in patients with Williams syndrome is usually associated with left-sided heart lesions, whereas right-sided endocarditis is rarely observed. This can be explained by the natural course of congenital heart lesions in Williams syndrome, in which right-sided heart lesions are likely to spontaneously regress with patient growth. We encountered a 29-year-old patient diagnosed with right-sided infective endocarditis. His diagnosis was supported by the modified Duke criteria, one major criterion of positive blood culture twice with Streptococcus oralis, a type of gram-positive viridance Streptococcus, and three minor criteria of the presence of congenital heart disease, persistent fever higher than 38.0℃, and spatial and temporal dissemination of septic pulmonary emboli. Although his supravalvular aortic stenosis remained mild, peripheral pulmonary stenosis was progressive even after adulthood, which might have been attributed to the development of right-sided infectious endocarditis, based on the biased distribution of septic emboli. Severely advanced caries with extensive tooth decay were not diagnosed until the development of IE because of intellectual disability and inability to report subjective symptoms. The subsequent development of diverticulitis after the treatment of infectious endocarditis was difficult to diagnose, and the management of this patient became more complicated. As the disease-specific pathophysiology progresses with age and adult Williams syndrome patients are less likely to express subjective symptoms, a multidisciplinary approach by the medical team comprised of cardiologists, nephrologists, gastroenterologists, dentists, and psychologists is needed in the management of Williams syndrome, particularly in adults in the process of becoming independent.