A 63-year-old man with a history of intravenous drug use (IVDU) and non-ischemic cardiomyopathy presented with one month of fevers, night sweats, and chest pain. Exam was notable for tachycardia (HR = 128), tachypnea (RR = 25), hypoxia (O2 Sat = 85% on RA), accessory muscle use, and crackles to the mid-lungs bilaterally. Labs revealed a leukocytosis of 23.4 K/µl, and CXR showed bilateral opacities. A transthoracic echocardiogram demonstrated possible tricuspid vegetation as well as a reduced ejection fraction of 16%. He was transferred to the ICU for management of sepsis from presumed endocarditis and pneumonia. Serial blood cultures demonstrated no growth, and a workup for culture-negative endocarditis was initiated. A subsequent transesophageal echocardiogram noted an absence of the previously seen tricuspid lesion. Due to the patient’s increasing oxygen requirements despite broad-spectrum coverage with Vancomycin and Zosyn, a CT Chest was performed, demonstrating extensive acute septic emboli. A serum 1,3-β-D-glucan (BDG) level was also found to be elevated at 295 pg/mL (normal < 60 pg/ml). Concomitantly, sputum cultures demonstrated a significant burden of budding yeast engulfed by PMNs, speciating into Candida albicans and tropicalis. The patient was started on amphotericin B and flucytosine with significant improvement of his hypoxemia and leukocytosis. He will be treated for a minimum of 6 weeks for candida endocarditis with serial BDG levels to monitor continued response to therapy.
Candida infective endocarditis (CIE) comprises less than 2% of all cases of infective endocarditis (IE), yet carries a significantly high mortality rate ranging from 30 to 80% despite advances in diagnostic testing and antimicrobial therapy. Risk factors include prolonged health care exposure, elderly age, IVDU, immunocompromised state, and prosthetic valve or endo-cavitary device. Although CIE is classically known for its propensity to develop bulky vegetations with embolic sequelae as well as for its persistent fungemia, the sensitivity of blood cultures for diagnosis of C. albicans endocarditis has been estimated at 50-75% and even lower for non-albicans CIE. Alternate diagnostic tests, such as the serum BDG, have shown great promise, with one prospective study finding this assay to have a sensitivity of 100% in the diagnosis of 18 patients with CIE. Vigorous Candidal growth on sputum stain, a significantly elevated serum BDG level, and marked clinical improvement in response to intravenous anti-fungal therapy all support a diagnosis of CIE in this patient.
This case highlights the potential value of serum BDG in accurately diagnosing CIE, a rare but potentially devastating infection. With its high sensitivity in detecting fungal endocarditis, hospitalists should consider ordering serum BDG in the workup of culture-negative infective endocarditis.