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Diagnosis of myocardial abscess secondary to infective endocarditis 18F-fluorodeoxyglucose positron emission tomography
Med Clin (Barc). 2017;148(4):e21–e22
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Letter to the Editor Diagnosis of myocardial abscess secondary to infective endocarditis 18 F-fluorodeoxyglucose positron emission tomography夽 Diagnóstico de absceso miocárdico por endocarditis infecciosa mediante tomografía de emisión de positrones con 18 F-fluorodesoxiglucosa Dear Editor, Although echocardiography and blood cultures represent the two basic tools for diagnosis of infectious endocarditis (IE), sometimes this can be difficult. Recently, performing nuclear cardiology techniques has been incorporated into the 2015 ESC guidelines1 in IE management, so as to complete the diagnosis of this condition in extremely difficult cases, such as endocarditis associated with metal prosthetic valve or cardiovascular implantable electronic devices. Other clinical situations where this additional test may help in the diagnosis of this infectious disease remain to be defined. We report the case of a 52-year-old male whom we treated in 2012, hypertensive and dyslipidemic, under monitoring by cardiology for chronic atrial fibrillation treated with rivaroxaban and bicuspid aortic valve with moderate aortic regurgitation. The patient came to the emergency room after 3 weeks on a trip to Bolivia for febrile symptoms (up to 40 ◦ C), plus skin lesions in the thenar eminence of the right hand. Given the cardiac history, admission for study was decided, where laboratory results showed a CRP of 290, no leukocytosis, mild hypertransaminasemia; a transthoracic echocardiography (TTE) showed a bicuspid aortic valve with moderate aortic regurgitation, with no imaging evidence indicative of IE. It was completed with a transoesophageal echocardiography (TEE), where no warts or other signs of IE were evident. Repeated blood cultures were positive for methicillin-sensitive Staphylococcus aureus. Given the blood culture findings and the underlying heart disease it was decided to initiate IV treatment with vancomycin and gentamicin, without achieving blood culture negativity, coinciding with the development of 35 bpm bradycardia. It was decided to implant a permanent pacemaker and the antibiotic treatment regimen was changed according to the antimicrobial susceptibility profile (daptomycin + gentamycin IV), performing a second TEE, which showed no changes from the first. Although the TEE proved inconclusive, and given the high suspicion of IE, together with the significant bradycardia, we decided to make a positron emission tomography with
Fig. 1. 18 FDG positron emission tomography showing a well-defined area of increased glycolytic activity in the outflow tract of the left ventricle, indicating the presence of an intramyocardial abscess (marked with an arrow).
夽 Please cite this article as: López-Aguilera J, López-Granados A, Mesa-Rubio D. Diagnóstico de absceso miocárdico por endocarditis infecciosa mediante tomografía de emisión de positrones con 18 F-fluorodesoxiglucosa. Med Clin (Barc). 2017;148:e21–e22.
18 F-fluorodeoxyglucose (18 FDG-PET/CT), which showed a welldefined area of increased glycolytic activity in the outflow tract of the left ventricle (Fig. 1 marked with an arrow), in the atrioventricular node area, indicating symptomatology of
˜ S.L.U. All rights reserved. 2387-0206/© 2016 Elsevier Espana,
e22
Letter to the Editor / Med Clin (Barc). 2017;148(4):e21–e22
infectious-inflammatory process in that area, which made the diagnosis of myocardial abscess possible. After starting the new antibiotic treatment regimen, blood cultures became negative and a new 18 FDG-PET/CT control was performed at 30 days, observing the disappearance of the glycolytic activity at the atrioventricular node. The patient was left with a moderate degree of aortic valve insufficiency, but this degree of aortic regurgitation progressively worsened to become severe, with left ventricular dilation, so in 2016, at the express wish of the patient, who did not want to start anticoagulation with warfarin, it was decided to perform an aortic valve replacement by bioprosthesis. The interest of this case is that IE can exist without suggestive signs in the TEE, despite the high sensitivity of this technique for diagnosis. It is important to consider the stage of the disease when the study is conducted; vegetations/abscesses may not be large enough so that they can be detected in a very early stage. It is in these cases where the 18 FDG-PET/CT can be very helpful to diagnose them. Although the basis of diagnosis of IE remain to be clinical suspicion, TTE-TEE and blood cultures, performing nuclear medicine imaging to complete the diagnosis of this disease has been recently incorporated into the 2015 ESC guidelines for IE management1 in patients with high suspicion of IE in which there are diagnostic difficulties with conventional echocardiography, such as the presence of IE on cardiovascular implantable electronic devices2 or metal prosthesis.3 In the latter clinical situation, it is even considered a major criterion for diagnosis when there is abnormal activity around the prosthetic valve implant site detected by 18 FDG-PET/CT (only if the prosthesis has been implanted for more than 3 months). Its use has also been proven for detecting peripheral embolism and metastatic infection in patients in acute heart infection stages,4 but so far, we have not found in the literature similar cases to the one we have reported here, in which this technique allowed
us not only the diagnosis of myocardial abscess (suspected by the patient’s severe bradycardia), but also helped to ensure the correct antimicrobial treatment, as serial testing confirmed the absence of activity detected by 18 FDG. In that way, performing emergency surgery to treat his myocardial abscess was avoided in the context of a subacute IE, undergoing surgery for his valvular disease 4 years into his follow-up through elective surgery, significantly decreasing surgical risk. References 1. Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, del Zotti F, et al. ESC guidelines for the management of infective endocarditis. Eur Heart J. 2015;36:3075–128. 2. Sarrazin JF, Philippon F, Tessier M, Guimond J, Molin F, Champagne J, et al. Usefulness of fluorine-18 positron emission tomography/computed tomography for identification of cardiovascular implantable electronic device infections. J Am Coll Cardiol. 2012;59:1616–25. 3. Pizzi MN, Roque A, Fernández-Hidalgo N, Cuéllar-Calabria H, Ferreira-González I, González-Alujas MT, et al. Improving the diagnosis of infective endocarditis in prosthetic valves and intracardiac devices with 18F-fluordeoxyglucose positron emission tomography/computed tomography angiography: initial results at an infective endocarditis referral center. Circulation. 2015;132:1113–26. 4. Van Riet J, Hill EE, Gheysens O, Dymarkowski S, Herregods MC, Herijgers P, et al. 18 F-FDG PET/CT for early detection of embolism and metastatic infection in patients with infective endocarditis. Eur J Nucl Med Mol Imaging. 2010;37:1189–97.
José López-Aguilera ∗ , Amador López-Granados, Dolores Mesa-Rubio Servicio de Cardiología, Hospital Universitario Reina Sofía, Córdoba, Spain, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Spain ∗ Corresponding author. E-mail address: [email protected] (J. López-Aguilera).
www.elsevier.es/medicinaclinica
Letter to the Editor Diagnosis of myocardial abscess secondary to infective endocarditis 18 F-fluorodeoxyglucose positron emission tomography夽 Diagnóstico de absceso miocárdico por endocarditis infecciosa mediante tomografía de emisión de positrones con 18 F-fluorodesoxiglucosa Dear Editor, Although echocardiography and blood cultures represent the two basic tools for diagnosis of infectious endocarditis (IE), sometimes this can be difficult. Recently, performing nuclear cardiology techniques has been incorporated into the 2015 ESC guidelines1 in IE management, so as to complete the diagnosis of this condition in extremely difficult cases, such as endocarditis associated with metal prosthetic valve or cardiovascular implantable electronic devices. Other clinical situations where this additional test may help in the diagnosis of this infectious disease remain to be defined. We report the case of a 52-year-old male whom we treated in 2012, hypertensive and dyslipidemic, under monitoring by cardiology for chronic atrial fibrillation treated with rivaroxaban and bicuspid aortic valve with moderate aortic regurgitation. The patient came to the emergency room after 3 weeks on a trip to Bolivia for febrile symptoms (up to 40 ◦ C), plus skin lesions in the thenar eminence of the right hand. Given the cardiac history, admission for study was decided, where laboratory results showed a CRP of 290, no leukocytosis, mild hypertransaminasemia; a transthoracic echocardiography (TTE) showed a bicuspid aortic valve with moderate aortic regurgitation, with no imaging evidence indicative of IE. It was completed with a transoesophageal echocardiography (TEE), where no warts or other signs of IE were evident. Repeated blood cultures were positive for methicillin-sensitive Staphylococcus aureus. Given the blood culture findings and the underlying heart disease it was decided to initiate IV treatment with vancomycin and gentamicin, without achieving blood culture negativity, coinciding with the development of 35 bpm bradycardia. It was decided to implant a permanent pacemaker and the antibiotic treatment regimen was changed according to the antimicrobial susceptibility profile (daptomycin + gentamycin IV), performing a second TEE, which showed no changes from the first. Although the TEE proved inconclusive, and given the high suspicion of IE, together with the significant bradycardia, we decided to make a positron emission tomography with
Fig. 1. 18 FDG positron emission tomography showing a well-defined area of increased glycolytic activity in the outflow tract of the left ventricle, indicating the presence of an intramyocardial abscess (marked with an arrow).
夽 Please cite this article as: López-Aguilera J, López-Granados A, Mesa-Rubio D. Diagnóstico de absceso miocárdico por endocarditis infecciosa mediante tomografía de emisión de positrones con 18 F-fluorodesoxiglucosa. Med Clin (Barc). 2017;148:e21–e22.
18 F-fluorodeoxyglucose (18 FDG-PET/CT), which showed a welldefined area of increased glycolytic activity in the outflow tract of the left ventricle (Fig. 1 marked with an arrow), in the atrioventricular node area, indicating symptomatology of
˜ S.L.U. All rights reserved. 2387-0206/© 2016 Elsevier Espana,
e22
Letter to the Editor / Med Clin (Barc). 2017;148(4):e21–e22
infectious-inflammatory process in that area, which made the diagnosis of myocardial abscess possible. After starting the new antibiotic treatment regimen, blood cultures became negative and a new 18 FDG-PET/CT control was performed at 30 days, observing the disappearance of the glycolytic activity at the atrioventricular node. The patient was left with a moderate degree of aortic valve insufficiency, but this degree of aortic regurgitation progressively worsened to become severe, with left ventricular dilation, so in 2016, at the express wish of the patient, who did not want to start anticoagulation with warfarin, it was decided to perform an aortic valve replacement by bioprosthesis. The interest of this case is that IE can exist without suggestive signs in the TEE, despite the high sensitivity of this technique for diagnosis. It is important to consider the stage of the disease when the study is conducted; vegetations/abscesses may not be large enough so that they can be detected in a very early stage. It is in these cases where the 18 FDG-PET/CT can be very helpful to diagnose them. Although the basis of diagnosis of IE remain to be clinical suspicion, TTE-TEE and blood cultures, performing nuclear medicine imaging to complete the diagnosis of this disease has been recently incorporated into the 2015 ESC guidelines for IE management1 in patients with high suspicion of IE in which there are diagnostic difficulties with conventional echocardiography, such as the presence of IE on cardiovascular implantable electronic devices2 or metal prosthesis.3 In the latter clinical situation, it is even considered a major criterion for diagnosis when there is abnormal activity around the prosthetic valve implant site detected by 18 FDG-PET/CT (only if the prosthesis has been implanted for more than 3 months). Its use has also been proven for detecting peripheral embolism and metastatic infection in patients in acute heart infection stages,4 but so far, we have not found in the literature similar cases to the one we have reported here, in which this technique allowed
us not only the diagnosis of myocardial abscess (suspected by the patient’s severe bradycardia), but also helped to ensure the correct antimicrobial treatment, as serial testing confirmed the absence of activity detected by 18 FDG. In that way, performing emergency surgery to treat his myocardial abscess was avoided in the context of a subacute IE, undergoing surgery for his valvular disease 4 years into his follow-up through elective surgery, significantly decreasing surgical risk. References 1. Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, del Zotti F, et al. ESC guidelines for the management of infective endocarditis. Eur Heart J. 2015;36:3075–128. 2. Sarrazin JF, Philippon F, Tessier M, Guimond J, Molin F, Champagne J, et al. Usefulness of fluorine-18 positron emission tomography/computed tomography for identification of cardiovascular implantable electronic device infections. J Am Coll Cardiol. 2012;59:1616–25. 3. Pizzi MN, Roque A, Fernández-Hidalgo N, Cuéllar-Calabria H, Ferreira-González I, González-Alujas MT, et al. Improving the diagnosis of infective endocarditis in prosthetic valves and intracardiac devices with 18F-fluordeoxyglucose positron emission tomography/computed tomography angiography: initial results at an infective endocarditis referral center. Circulation. 2015;132:1113–26. 4. Van Riet J, Hill EE, Gheysens O, Dymarkowski S, Herregods MC, Herijgers P, et al. 18 F-FDG PET/CT for early detection of embolism and metastatic infection in patients with infective endocarditis. Eur J Nucl Med Mol Imaging. 2010;37:1189–97.
José López-Aguilera ∗ , Amador López-Granados, Dolores Mesa-Rubio Servicio de Cardiología, Hospital Universitario Reina Sofía, Córdoba, Spain, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Spain ∗ Corresponding author. E-mail address: [email protected] (J. López-Aguilera).