Case presentation
A diabetic 26-year-old man was admitted to our center due for prolonged
fever. He had no history of rheumatic or congenital heart disease. He
had been well until three weeks ago, when he began to have fatigue and
general malaise, as well as loss of appetite. At admission, the patient
was febrile at 39°C and tachycardic. His lung sounds were clear, and no
cardiac murmur was audible. There were no signs of heart failure.
The laboratory tests showed an inflammatory syndrome. An
echocardiographic evaluation revealed a normal global systolic left
ventricular function, no valvular disease but we noted a 15 x 11 mm
mobile oscillating large mass with anechogenic content attached to the
mitral anterolateral papillary muscle (Figure 1 ).
Despite the intravenous antibiotic therapy, fever had persisted. A
thoraco-abdominal computed tomography revealed multiple hypodensities of
the brain, the liver and the spleen consistent with septic emboli. The
usual blood cultures were negative and these results were attributed to
prior antibiotics. Few days after hospitalization, the patient’s
clinical condition worsened and pulmonary congestion appeared suddenly.
The physical examination revealed a new pansystolic murmur consistent
with mitral regurgitation. There was no electrocardiographic change
suggesting an acute or subacute myocardial infarction.
Transthoracic echocardiography (TTE) and transesophageal
echocardiography (TEE) examinations were repeated. Echocardiographic
studies showed a hyperdynamic left ventricle with no regional
wall-motion abnormality but we noticed severe mitral regurgitation with
a prolapse of the anterior mitral valve due to the rupture of the mitral
anterolateral papillary muscle, which explained the patient clinical
status (Figure 2 ). The diagnosis of IE complicated by severe
mitral regurgitation was established. The patient was admitted to
intensive care unit for stabilization with medical therapy. Then, he
underwent urgent prosthetic mitral valve replacement. On surgical
inspection, total complete rupture of the tip of anterolateral papillary
muscle was found (Figure 3 ).
The histologic examination of the resected tissues revealed a
non-specific inflammation with fibrosis. The valve culture was negative.
Given the histologic examination results, the diagnosis was a mitral
valve IE complicated by anterolateral papillary muscle rupture due to
direct germ invasion. After 8 weeks of IV antibiotic therapy, the
patient was uneventfully discharged.