Acute Mitral Regurgitation of Unknown Etiology Associated with Disseminated Intravascular Coagulation Eventually Diagnosed as Enterococcus Faecalis Infective Endocarditis by Mitral Valve Surgery

Abstract

BACKGROUND Infective endocarditis is prevalent worldwide and the modified Duke criteria have been used universally to diagnose this condition. However, making the correct diagnosis is rather difficult because the clinical presentation and findings of blood tests are non-specific. CASE REPORT A 70-year-old female complaining of dyspnea for 5 days with acute mitral regurgitation was transferred to our hospital. She had acute heart and respiratory failure and disseminated intravascular coagulation. Although infective endocarditis was suspected, repeated blood cultures and transesophageal echocardiography could not reveal any findings of infective endocarditis. Because the etiology of her condition was not determined by various examinations, mitral annuloplasty was required to treat her mitral regurgitation, and was performed for definitive diagnosis and treatment revealing the presence of vegetation on the mitral valve. Enterococcus faecalis was detected by cultures of the mitral valve and blood after the surgery. CONCLUSIONS It can be very difficult to diagnose infective endocarditis correctly, especially when a case fails to fulfill the modified Duke criteria. In such a case, only cardiac surgery might enable us to make an accurate diagnosis and save a patient's life.

Figure 1.

Transthoracic echocardiography performed on admission. (A) Brightness mode image, (B) color Doppler image, and (C) pulse Doppler image. Ejection fraction of 70%, left atrial volume index of 66 mL/m² and posterior wall thickening of 14 mm are shown. Mitral regurgitation (grades III to IV) and prolapse of posterior mitral leaflet P3 are revealed (B, C) without findings of vegetation and wall motion abnormalities (A).

Figure 2.

First transesophageal echocardiography performed following transthoracic echocardiography. (A) Brightness mode image and (B) color Doppler image. Prolapse of posterior mitral leaflet P3 (arrow) and ruptured chordae tendineae (arrowhead) are shown without the finding of vegetation and hyperplasia of valves (A). The mitral regurgitation jet runs from the site of prolapse to left atrial appendage along the anterior leaflet (B).

Figure 3.

Brain magnetic resonance imaging. (A) Diffusion-weighted image taken on day 12, (B) apparent diffusion coefficient (ADC) image taken on day 12, (C) diffusion-weighted image taken on day 67, and (D) ADC image taken on day 67. On day 12, the diffusion-weighted image shows high signal intensity in the right temporoparietal lobe (arrow, A) and ADC value of the lesion is low to equal (arrow, B). On day 67, the diffusion-weighted image shows high signal intensity in the left putamen (arrow, C) and ADC value of the lesion is low to equal (arrow, D). Images of these lesions are compatible with sub-acute to acute phase cerebral infarction, which is considered to be caused by cardiogenic emboli because of the involvements of both sides of the brain.

Figure 4.

Intraoperative findings of the mitral valve. Widespread attachment of vegetation on the mitral valve (arrows) and prolapse of posterior mitral leaflet P3 (arrowhead) are shown.