Sterile Endocarditis and Splenic Infarct: A Rare Masquerading Presentation of Granulomatosis With Polyangiitis in a Patient With Pulmonary Aspergillosis

Granulomatosis with polyangiitis (GPA) is a rare multisystem disease characterized by vasculitis affecting small vessels, resulting in the formation of necrotising granulomata, primarily affecting the lungs, the upper respiratory tract, and kidneys. Almost all patients have upper and lower respiratory involvement; up to 85% of patients with GPA develop kidney disease within two years of diagnosis. Cutaneous, neurological, and ocular manifestations are also seen with varying frequencies. However, cardiac manifestations of the disease are rare and scarcely reported in the literature. Here, we report a case of a 65-year-old female with an initial diagnosis of pulmonary aspergillosis based on the presence of septate hyphae branching at acute angles on lung biopsy and elevated serum galactomannan, who, over the following months, developed a multitude of issues such as myocardial infarction, sterile endocarditis, splenic infarction, and heart block, as well as the challenges faced in establishing a diagnosis and managing its complications.