A 24-year-old woman presents to the emergency department with symptoms of fever, chills and rigors. On physical examination, she looks unwell; the temperature is 39.4degC, blood pressure 100/60 mm Hg, pulse 110/min, and oxygen saturation 95%. There is a 3/6 pansystolic murmur at the right sternal border, which increases with inspiration. Her arms have multiple tattoos and needle marks from injection drug use. Blood cultures (2/2 sets) are positive for S aureus, and she is started on appropriate antibiotics. Her renal function is mildly impaired and her urinalysis is positive for protein, and microscopy reveals red cell casts. Which of the following mechanisms is the most likely explanation for her renal abnormalities?
High-Yield Explanation
Glomerulonephritis, arthritis, and many of the mucocutaneous lesions are secondary to circulating immune complexes. The clinical manifestations of infective endocarditis are a result of three factors: (1) direct infection in the heart, (2) septic emboli, and (3) high levels of circulating immune complexes. Renal emboli cause hematuria and flank pain, but rarely impair renal function.