Severe pulmonic valve regurgitation due to histoplasma endocarditis

Abstract

A 67-year-old man with myelodysplastic syndrome, disseminated histoplasmosis, and mitral valve replacement presented with dyspnea and peripheral edema. Transthoracic echocardiography demonstrated abnormal pulmonic valve with possible vegetation. Color flow imaging showed laminar flow from main pulmonary artery into right ventricular outflow tract (RVOT) in diastole. The continuous wave Doppler signal showed dense diastolic envelope with steep deceleration slope. These findings were consistent with severe pulmonic valve regurgitation, possibly due to endocarditis. Transesophageal echocardiography demonstrated an echodense mass attached to the pulmonic valve. The mitral valve bioprosthesis appeared intact. Bacterial and fungal blood cultures were negative; however, serum histoplasma antigen was positive. At surgery, the valve appeared destroyed by vegetations. Gomori methenamine silver-stains showed invasive fungal hyphae and yeast consistent with a dimorphic fungus. Valve cultures grew one colony of filamentous fungus. Itraconazole was continued based on expert infectious diseases diagnosis. After surgery, dyspnea and ankle edema resolved. To the best of our knowledge, histoplasma endocarditis of pulmonic valve has not been previously reported. Isolated pulmonic valve endocarditis is rare, accounting for about 2% of infectious endocarditis (IE) cases. Fungi account for about 3% of cases of native valve endocarditis. Characterization of pulmonary valve requires thorough interrogation with 2D and Doppler echocardiography techniques. Parasternal RVOT view allowed visualization of the pulmonary valve and assessment of regurgitation severity. As an anterior structure, it may be difficult to image with transesophageal echocardiography. Mid-esophageal right ventricular inflow-outflow view clearly showed the pulmonary valve and vegetation.

Learning points: Identification and characterization of pulmonary valve abnormalities require thorough interrogation with 2D and Doppler echocardiography techniques.Isolated pulmonary valve IE is rare and requires high index of suspicion. Histoplasma capsulatum IE is rare and requires high index of suspicion.

Figure 1

(A) Tongue lesion – the initial presentation of disseminated histoplamosis; (B) transthoracic echocardiogram: abnormal pulmonic valve with possible vegetation; (C) transthoracic echocardiogram: the continuous wave Doppler signal at the pulmonic valve showing dense diastolic envelope with a steep deceleration slope; (D) transesophageal echocardiogram: 1.4 cm×0.8 cm echodense mass attached to one of the cusps of the pulmonic valve; (E) intraoperative view of the pulmonic valve; (F) excised pulmonic valve; (G) one of the pulmonic valve cusps with attached vegetation; (H) gomori methenamine silver-stained sections of pulmonary valve showing invasive fungal hyphae and yeast.