Nutritionally Variant Streptococcal Endocarditis in a Structurally Normal Pediatric Heart: An Abstract from Akron Children’s Hospital Resident and Fellow Academic Day

Background: Infective endocarditis (IE) in children is most often associated with congenital heart disease (CHD). In those with structurally normal hearts, risk factors include indwelling central venous catheters and rheumatic heart disease. Staphylococcus aureus is the most common cause of IE in children without CHD, while viridans streptococci predominate in those with CHD. Patient Case: A previously healthy 13-year-old male presented with 2 days of right upper quadrant abdominal pain, emesis, and fever (38°C). 4 days earlier, he sustained blunt abdominal trauma from a football helmet. Vital signs and physical examination were notable only for right costovertebral and right upper quadrant tenderness. Initial laboratory evaluation was remarkable for elevated CRP, mild leukocytosis, and hyponatremic dehydration (Table 1). Blood and urine cultures were obtained. Abdominal CT revealed a wedge-shaped right renal lesion concerning for pyelonephritis, infarct, or mass. He received broad-spectrum antibiotics for presumed pyelonephritis with symptomatic improvement and was discharged on oral antibiotics despite a negative urine culture. 4 days after collection and 2 days after discharge, his blood culture grew Streptococcus abiotrophia/granulicatella, also known as nutritionally variant streptococcus (NVS). Echocardiogram revealed a small aortic valve vegetation with normal cardiac structure and function. He was started on IV penicillin and gentamicin. He remained afebrile, and a repeat echocardiogram after 4 days showed decreased vegetation size. He completed a 4-week IV antibiotic course. Conclusions/Novel Insights: NVS are normal human flora that have the potential to cause IE, osteomyelitis, and sepsis. They have specific nutritional needs, thus making them challenging to grow in vitro. Although NVS are confirmed in 1-3% of all IE cases, these difficult-to-isolate organisms may be causative in culture-negative IE, making true prevalence unknown. Clinical presentation may be nonspecific, with symptoms such as low-grade fever and malaise. IE caused by NVS has an increased incidence of septic emboli, mortality, and treatment failure as compared to other streptococci. In this case, the renal lesion was retrospectively diagnosed as an infarct from a septic embolus. Clinicians should consider echocardiography and extended culture monitoring in children with NVS bacteremia. These organisms are challenging to detect, can cause severe disease, and carry a poorer prognosis compared with more common streptococcal pathogens.