Fever of unknown origin – neither endocarditis nor myocardial infarction

    Authors

    Keywords

    infection, heterophile antibodies, valve mass

    DOI

    https://doi.org/10.15836/ccar2022.207

    Full Text

    **Case report**: 61-year-old woman presented to the Emergency Department with sudden onset of fever, shortness of breath, headache, arthralgia, upper-abdominal pain and generalised maculoerythematous rash. Laboratory testing showed pancytopenia, slightly elevated C-reactive protein, normal procalcitonin value and altered hepatogram with unconjugated hyperbilirubinemia. An abdominal ultrasound confirmed hepatosplenomegaly. Electrocardiographic findings were unspecific. Fever, heart murmur, elevated values of cardiac troponin and N-terminal pro b-type natriuretic peptide (NT-proBNP) raised clinical suspicion of endocarditis. Transthoracic echocardiography found thickening and potential vegetation on the aortic valve. Besides that, there were signs of hypertensive heart disease with preserved left ventricle ejection fraction, no wall motion abnormalities, normal right ventricular size and function and insignificant valve dysfunction. Transesophageal echocardiography showed round, well-circumscribed, wide-based, hyperechogenic structure on noncoronary cusp. Multiple blood cultures were negative. Since Duke criteria were not met, more plausible diagnoses of Arantius nodule or fibroelastoma were considered. High sensitive troponin I (Hs-TnI) values were persistently elevated without dynamic changes or clinical correlation. In the setting of acute (especially viral) infection, heterophile antibodies can cause interference and positive or negative results. Different immunoassay in another laboratory showed normal Hs-TnI, thus confirming false-positive results. Extensive workup did not confirm infective pathogen but nevertheless patient has recovered completely (Figure 1). FIGURE 1. Transesophageal echocardiogram images: thickening on the aortic valve (A); round, well-circumscribed, wide-based, hyperechogenic structure on noncoronary cusp (B); trace aortic regurgitation (C). **Conclusion**: Clinical history and physical examination are crucial since laboratory and imaging results can be misleading. Guideline based approach for the diagnosis of myocardial infarction and endocarditis helps to avoid false positive diagnosis (1-3).

    Literature

    1. Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, Del Zotti F, et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM). Eur Heart J. 2015 November 21;36(44):3075–128. https://doi.org/10.1093/eurheartj/ehv319
    2. Lakusic N, Sopek Merkas I, Lucinger D, Mahovic D. Heterophile antibodies, false-positive troponin, and acute coronary syndrome: a case report indicating a pitfall in clinical practice. Eur Heart J Case Rep. 2021 February 4;5(2):ytab018. https://doi.org/10.1093/ehjcr/ytab018
    3. Graça Santos L, Ribeiro Carvalho R, Montenegro Sá F, Soares F, Pernencar S, Castro R, et al. Circulating Heterophile Antibodies Causing Cardiac Troponin Elevation: An Unusual Differential Diagnosis of Myocardial Disease. JACC Case Rep. 2020 March 18;2(3):456–60. https://doi.org/10.1016/j.jaccas.2020.01.011
    Cardiologia Croatica
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    Fever of unknown origin – neither endocarditis nor myocardial infarction

    Extended Abstract
    Issue9-10
    Published
    Pages207
    PDF via DOIhttps://doi.org/10.15836/ccar2022.207
    infection
    heterophile antibodies
    valve mass

    Authors

    Tereza Knaflec*ORCIDZabok General Hospital and Hospital of Croatian Veterans, Zabok, Croatia
    Siniša RoginićORCIDZabok General Hospital and Hospital of Croatian Veterans, Zabok, Croatia
    Martina RoginićORCIDZabok General Hospital and Hospital of Croatian Veterans, Zabok, Croatia
    Marija ČajkoORCIDZabok General Hospital and Hospital of Croatian Veterans, Zabok, Croatia
    Nikolina Mijač MikačićORCIDZabok General Hospital and Hospital of Croatian Veterans, Zabok, Croatia
    Domagoj FutivićORCIDZabok General Hospital and Hospital of Croatian Veterans, Zabok, Croatia

    *Correspondence email: tknaflec@gmail.com

    Full Text

    Case report: 61-year-old woman presented to the Emergency Department with sudden onset of fever, shortness of breath, headache, arthralgia, upper-abdominal pain and generalised maculoerythematous rash. Laboratory testing showed pancytopenia, slightly elevated C-reactive protein, normal procalcitonin value and altered hepatogram with unconjugated hyperbilirubinemia. An abdominal ultrasound confirmed hepatosplenomegaly. Electrocardiographic findings were unspecific. Fever, heart murmur, elevated values of cardiac troponin and N-terminal pro b-type natriuretic peptide (NT-proBNP) raised clinical suspicion of endocarditis. Transthoracic echocardiography found thickening and potential vegetation on the aortic valve. Besides that, there were signs of hypertensive heart disease with preserved left ventricle ejection fraction, no wall motion abnormalities, normal right ventricular size and function and insignificant valve dysfunction. Transesophageal echocardiography showed round, well-circumscribed, wide-based, hyperechogenic structure on noncoronary cusp. Multiple blood cultures were negative. Since Duke criteria were not met, more plausible diagnoses of Arantius nodule or fibroelastoma were considered. High sensitive troponin I (Hs-TnI) values were persistently elevated without dynamic changes or clinical correlation. In the setting of acute (especially viral) infection, heterophile antibodies can cause interference and positive or negative results. Different immunoassay in another laboratory showed normal Hs-TnI, thus confirming false-positive results. Extensive workup did not confirm infective pathogen but nevertheless patient has recovered completely (Figure 1).

    FIGURE 1. Transesophageal echocardiogram images: thickening on the aortic valve (A); round, well-circumscribed, wide-based, hyperechogenic structure on noncoronary cusp (B); trace aortic regurgitation (C).

    Conclusion: Clinical history and physical examination are crucial since laboratory and imaging results can be misleading. Guideline based approach for the diagnosis of myocardial infarction and endocarditis helps to avoid false positive diagnosis (1–3).

    Literature

    1. 1.
      Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, Del Zotti F, et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM). Eur Heart J. 2015 November 21;36(44):3075–128.DOI
    2. 2.
      Lakusic N, Sopek Merkas I, Lucinger D, Mahovic D. Heterophile antibodies, false-positive troponin, and acute coronary syndrome: a case report indicating a pitfall in clinical practice. Eur Heart J Case Rep. 2021 February 4;5(2):ytab018.DOI
    3. 3.
      Graça Santos L, Ribeiro Carvalho R, Montenegro Sá F, Soares F, Pernencar S, Castro R, et al. Circulating Heterophile Antibodies Causing Cardiac Troponin Elevation: An Unusual Differential Diagnosis of Myocardial Disease. JACC Case Rep. 2020 March 18;2(3):456–60.DOI