Attending Physician Cedars-Sinai Medical Center Los Angeles, California, United States
Abstract:
Introduction: Prosthetic valve endocarditis (PVE) is an endovascular, microbial infection occurring on parts of a valve prosthesis or on reconstructed native heart valves. In patients with post Tetralogy of Fallot repair, due to RVOT surgery, the patient is left with progressive RVOT dysfunction. Treatment for RVOT dysfunction has historically required surgical placement of a new conduit or bioprosthetic valve, both of which have a limited lifespan. The FDA approved Melody valve for transcatheter pulmonary valve implantation in 2010. The risk of infective endocarditis after implantation of the melody valve is significant. The outcome can be favorable when Streptococci are the causative organism, and the right ventricular outflow tract is not obstructed. Outcomes after infection with rare organisms like Lactobacillus are not known in pediatric patients.
Case Description: A 17-year-old male with past history of developmental delay, Tetralogy of Fallot s/p repair, bilateral pulmonary angioplasty, s/p left pulmonary artery stenting and transcatheter Melody pulmonary valve replacement , s/p subaortic membrane resection and inspection of aortic valve, SVT/V-tach, with single ventricle AICD placement was admitted to PICU after a near syncopal episode with extreme fatigue with fever. Patient had a series of mild upper respiratory tract infections for 3 months prior to admission. After recent recovery from URI, patient developed intermittent fevers (Tmax 102) for 5 days before admission. He also had worsening fatigue and dyspnea. Upon admission, patient was found to have bacteremia with a "gram positive rod," further identified as Lactobacillus rhamnosus. Initial antibiotic therapy included Ceftriaxone, Gentamicin and Vancomycin. TTE upon admission was concerning for thickened Melody valve leaflets. RVOT gradient was not significant. Given these findings, it was confirmed that patient did indeed have infective endocarditis with Lactobacillus in the context of a prosthetic pulmonary valve (Melody valve). He completed treatment with IV antimicrobials (penicillin) including synergistic aminoglycoside initially (gentamicin) to appropriately treat and clear this infection. Duration of treatment was 6-weeks. There were no odontogenic foci of infection noted on CT facial bones. No clear source of lactobacillus was identified.
Discussion: There have been several case reports of Lactobacillus rhamnosus bacteremia with subsequent endocarditis in the adult population, however there is sparse data, particularly those with underlying complex cardiac history in pediatrics. Several reports in adults have been linked to recent upper endoscopies, probiotic use, or poor dental hygiene. To our knowledge, this was the first reported case of Lactobacillus endocarditis in a pediatric patient with Melody valve placement who completed therapy with IV antibiotics without need for further surgical intervention. The diagnosis of infective endocarditis in the setting of melody valve can be challenging as the modified Duke criteria have a modest diagnostic yield in this setting. Approximately 52% of patients require reintervention, either surgically or percutaneously in adults. Therefore, timely diagnosis and intervention is necessary in these patients.
