A 50-year-old man presented to our hospital with one month of dyspnea on exertion and lower extremity edema. Two weeks prior to admission, he was hospitalized at another institution with decompensated heart failure, severe mitral regurgitation, and possible pneumonia. He received diuretics and antibiotics and his symptoms improved. He was referred to our hospital to evaluate his mitral valvulopathy.
Past medical history included heart failure due to mitral valve regurgitation, atrial fibrillation, pulmonary thromboembolism, and inflammatory polyarthritis. Two years prior to admission, he underwent mitral valve revision complicated by recurrent mitral regurgitation and new tricuspid regurgitation requiring bioprosthetic mitral valve replacement and tricuspid valve repair. Histopathology of the extracted mitral valve revealed fibrosis, and valvular tissue cultures were not obtained.
He complained of arthralgias that were controlled on colchicine and also epigastric abdominal pain. He denied fever, weight loss, or diarrhea. Other medications included carvedilol, furosemide, and warfarin. He had no medication allergies. There was no foreign travel, illicit drug, alcohol, or tobacco use. He was a retired welder.
Physical examination revealed a well-developed, well-nourished man who appeared fatigued in moderate respiratory distress. Temperature 37.3°C, blood pressure 98/86 mmHg, heart rate 115, respiratory rate 25, and oxygen saturation 95% on 3 liters of oxygen via nasal cannula. He had increased jugular venous distension, bilateral basilar crackles, grade III/VI holosystolic murmur in the mitral area, and bilateral lower extremity edema. There were no cutaneous stigmata of endocarditis. The remainder of his exam was normal.
Laboratory results revealed anemia and elevations of total bilirubin, alkaline phosphatase, and B-type natriuretic peptide. Computed tomography of the chest and abdomen revealed bilateral ground-glass opacities consistent with edema, a right pleural effusion, and mild mediastinal and retroperitoneal lymphadenopathy.
He was admitted to the cardiac care unit and begun on furosemide and dobutamine infusions. A transthoracic echocardiogram revealed two small mobile echo-densities on the prosthetic mitral valve consistent with vegetations. On hospital day 3, admission blood cultures remained negative and transesophageal echocardiogram revealed a 1.1-centimeter mobile structure on the prosthetic mitral valve with severe regurgitation. Additional blood cultures were obtained and held for 14-days. Serologies for Bartonella sp. and Coxiella burnetti were negative. He was begun on intravenous vancomycin, gentamicin, and cefepime for culture-negative PVE. Cardiovascular surgery was consulted, and he underwent a bioprosthetic mitral valve replacement on hospital day 9. The extracted valve (Fig. 1) was sent for cultures and broad-range PCR for bacterial, fungal, and mycobacterial organisms. Histopathology revealed vegetations with chronic inflammation.
Extracted prosthetic mitral valve. Both leaflets appeared perforated. There were no vegetations or thrombi seen macroscopically. At the time of surgery, the infected valve annulus had been debrided. Scale marker in centimeters.
Antibiotics were continued and he developed dialysis-dependent renal failure on hospital day 12. His antibiotics were transitioned to intravenous vancomycin, ceftriaxone, and ampicillin, and on hospital day 20 he was discharged on this regimen to complete a 6-week course. Blood and extracted valve cultures remained negative for microbial growth and he was maintained on hemodialysis.
On post-discharge day 5, broad-range PCR from the extracted prosthetic mitral valve returned positive for Tropheryma whipplei. In addition, Periodic-acid-Schiff (PAS) stain revealed macrophages containing granular PAS-positive material consistent with T. whipplei organisms (Fig. 2). Antibiotics were consolidated to monotherapy with intravenous ceftriaxone and after six weeks of therapy he improved with only mild residual dyspnea. After discussion with nephrology, he was transitioned to oral trimethoprim-sulfamethoxazole with plans to treat for at least twelve months.
Prosthetic valve specimen. Hematoxylin and eosin stain (panel A). Granular periodic-acid-Schiff stain positive material consistent with T. whipplei organisms (panel B, see arrow). Both panels are at 20x magnification.