Disseminated Nocardiosis with Possible Eustachian Valve Endocarditis Masquerading as a Right Atrial Mass

Nocardiosis is an uncommon bacterial infection that can infect any organ, but its cardiac involvement is particularly rare. This case report describes a unique presentation of disseminated nocardiosis with a calcified mass in the right atrium arising from the Eustachian valve, a possible vegetation, a condition not previously reported. This case highlights the importance of cardiac evaluation in all cases of nocardiosis. We present the case of a 28-year-old male paddy field worker from Kerala, India, with no known immunodeficiency and no history of intravenous drug abuse, who presented with prolonged fever of 2 months’ duration and multiple lower limb abscesses that were unresponsive to multiple antibiotic courses and drainage. Despite sterile initial cultures, he developed a rapid deterioration of vision in his right eye due to a retinal abscess. A two-dimensional transthoracic echocardiogram revealed a hyperechoic mass in the right atrium, arising from the Eustachian valve of the inferior vena cava. Subsequent staining and culture of aspirate from an abscess identified a Gram-positive, variably acid-fast, branched filamentous bacterium, confirming a diagnosis of disseminated nocardiosis with possible Eustachian valve endocarditis. The patient was successfully treated with a prolonged course of trimethoprim-sulfamethoxazole (Septran DS), moxifloxacin, and amikacin. Within 2 weeks, his fever subsided, and his abscesses began to heal. At a 6-month follow-up, his vision had fully recovered, and the cardiac mass remained. Since it was calcified and immobile, not causing any hemodynamic issues, it was left alone. This case report underscores the need to consider Nocardia as a potential cause of infective endocarditis, even in immunocompetent individuals, and suggests that cardiac imaging should be the part of the standard workup for patients with disseminated nocardiosis This is the first documented case of Eustachian valve endocarditis caused by Nocardia .