Native Valve Infective Endocarditis Caused by Histoplasma capsulatum in an Immunocompetent Host: The First Case in Asia and Literature Review in Asia and Australia

Abstract

Background. Infective endocarditis caused by the dimorphic fungus Histoplasma capsulatum is extremely rare, occurring predominantly in individuals with prosthetic heart valves and HIV infection. To our knowledge, no case of H. capsulatum native valve endocarditis has been reported in Asia. Methodology. A descriptive study was carried out at King Chulalongkorn Memorial Hospital, Bangkok, Thailand, in 2020. Results. A previously healthy 34-year-old man developed fever, umbilicated skin lesions, oral ulcers, hoarseness of voice, severe weight loss, and progressive dyspnea over the course of one week. Facial umbilicated papules, nodular ulcers in his tongue and palate, a diastolic rumbling murmur at the mitral valve, diffuse fine crackles in both lungs, and engorged neck veins were detected during the examination. Skin scraping of the facial lesion revealed both extracellular and intracellular yeasts with buddings, 2–4 μm in size on Wright’s stain. Transthoracic echocardiography demonstrated a left ventricular ejection fraction of 54 percent, severe rheumatic mitral stenosis, and multiple oscillating masses in the anterior mitral valve leaflet ranging in dimension from 1.5 to 2.4 cm. The HIV antibody test was negative. H. capsulatum endocarditis was diagnosed, and liposomal amphotericin B was administered. Due to cardiogenic shock, emergency open-heart surgery was conducted one day after admission. However, he died of multiorgan failure four days after the operation. The skin and vegetation cultures finally grew H. capsulatum after 1 week of incubation. Conclusions. To date, there has been handful of cases of H. capsulatum native valve endocarditis in non-HIV-infected patients. We report herein the first case in Thailand. Umbilicated skin lesions, especially combined with oral mucosal lesions, are a clinical clue that leads to the correct diagnosis of the causative organism.

“Not much room for mushrooms” in the heart: knowns and unknowns of fungal infective endocarditis

“…Cerebrospinal fluid was examined in two patients with a Cryptococcus infection [100,102] and in one with a Volvariella endocarditis [125] . A urine examination was performed on three patients infected with Histoplasma [104,106,107] . Skin lesions and skin appendages were examined in cases with Histoplasma [105] , Trichosporon [111] , and Fusarium [112] .…”

“…Most of the cases underwent computer tomographic (CT) imaging and MRI of the brain, thorax, abdomen, and pelvis, as well as CT-angiography, encompassing almost all infective species involved. A positron emission tomography or PET/CT scan was performed in order to confirm or exclude other septic foci for various fungal species such as Candida [50,60,69,80] , Aspergillus [96,97] , and other infective agents [104,119] . and delay of diagnosis of > 30 days showed no significant effect.…”

“…After discussion with clinical laboratory experts, serial blood testing or incubation for several weeks can be considered necessary since these organisms are fastidious [41,55,64,90,102,107,118] . So-called negative results should not be discarded [86,96,102,104] . Candida is likely to be recovered as a causative agent in blood cultures, but a timely diagnosis of Aspergillus endocarditis remains elusive.…”

“…Aspergillus endocarditis was diagnosed postmortem in approximately one third of cases and was diagnosed preoperatively in less than half of patients [97] . For Histoplasma, serologic examination can be performed [106] , which is useful in areas where this organism is endemic [104,106,107] . Another difficulty arises when bacteria and fungi are identified simultaneously [73,77,78,103] or cultures are positive for bacteria without demonstration of fungi, while the latter can be found in the excised valve, indicating a mixed infection.…”

“…It was administered in patients with C. parapsilosis [45,46,[49][50][51][52] and other Candida species [63,65,70] or a combination of Candida with a bacterial IE [74,75,77] , but not in patients with C. albicans infection. It has also been applied in several species of Aspergillus [81,82,[84][85][86][87]89,90,92,[95][96][97][98] , one patient with Cryptococcus [100] , all patients with Histoplasma [104][105][106][107] and Trichosporon [109][110][111][112] , as well as in some other fungal species [112,113,116,117,[121][122][123][124] . Nevertheless, it was reduced in dosage in one of the cases [124] and had to be discontinued in two other cases with renal failure [116,121] .…”