Winning Abstracts from the 2011 Medical Student Abstract Competition: Pacemaker Extrusion from Pseudomonas aeruginosa: An Unusual Presentation from an Unlikely Culprit
Author: Ryan G. Hartman, MS, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Class of 2011
Introduction: Infections of cardiac implantable electronic devices (CIED) are an infrequent complication occurring with an incidence of 1 to 7%. Extrusion is a recognized manifestation of CIED infection and is the migration of a device from its pocket site to the overlying skin with evidence of visible device or leads. According to a retrospective study conducted in 2007, extrusion of CIEDs complicates CIED infections in 32% of cases. Of these cases, 89% were attributed to Staphylococcus infections. We report a case of Pseudomonas aeruginosa culture proven pacemaker extrusion.
Case Presentation: We present a 51-year-old African American male with a past medical history significant for complicated diabetes mellitus, ischemic cardiomyopathy with an ejection fraction of 35%, a surgically repaired ventricular septal defect, and pacemaker dependence due to complete atrioventricular block. His dual chamber pacemaker was initially implanted in 1996 and later upgraded to an implantable cardiac defibrillator (ICD). Ten months after ICD implantation, he presented with a CIED extrusion but exhibited no signs of systemic/local infection or inflammation. A transesophageal echocardiogram was negative for vegetation. Intravenous vancomycin was started empirically and the CIED was later extracted on hospital day 7. Cultures of the pulse generator pocket grew P. aeruginosa, whereas cultures of the leads cultivated P. aeruginosa and Staphylococcus epidermidis. Blood cultures remained negative. Vancomycin was changed to daptomycin and cefepime was added for broader coverage. The pulse generator was re-implanted on the contralateral chest wall two days later. He was discharged on a 6 week course of intravenous cefepime and oral ciprofloxacin.
Discussion: A review of the literature revealed that Pseudomonas-related CIED infections often coincide with remote infections leading to hematologic seeding or proximity to exposed gastrointestinal flora. Our patient had neither. Late onset CIED infections, occurring 12 weeks to one year post-implant typically present without systemic manifestations or local inflammation, as was seen with our patient. However, most were attributed to Staphylococcal infections. Since a clinical cure was achieved with cefepime, we suggest that it be used to treat CIED infections caused by P. aeruginosa when antibiotic susceptibility data indicate that it is efficacious. It is hoped that an organization like the American Heart Association will add to their guideline recommendations about optimal screening, management and prevention of Pseudomonas-related CIED infections.