The clinical manifestation of embolic nephritis depends on the size of the embolus as well as the embolism site, and the degree of the embolism. In small cases, the patient can have no symptoms and only show microscopic hematuria or proteinuria; in large cases, severe back pain can occur suddenly, similar to renal colic caused by kidney stones, and often appearing as flesh-eye hematuria. You should go to the nephrology department of a regular hospital for examination, such as liver function, ultrasound monitoring of the affected area, and routine urine examination. The bacteria causing infective endocarditis or their products are used as antigens to produce the corresponding antibodies, and the two form a circulating immune complex. The site of deposition of the immune complex in the glomerulus is related to the type of bacteria and the period of infection, but depends mainly on the size and solubility of the antigen-antibody complex. The pathogenesis of renal damage caused by infected endocardium is generally considered to be microembolism as the cause of focal nephritis, but immunofluorescence and electron microscopy provide important evidence for the pathogenesis of immune complexes. Immunofluorescence staining in diffuse and focal glomerulonephritis showed similar manifestations, mainly as diffuse granular C3 deposition along the capillary wall. Immunoglobulin (mainly IgG) deposits are also present in the capillary wall and thylakoid region. Some immunofluorescent deposits in focal nephritis may also be seen in glomeruli that appear to be normal. Deposits with increased electron density are usually not seen in focal glomerulonephritis, whereas they occur frequently in diffuse glomerulonephritis, mostly between the glomerular basement membrane and endothelial cells and within the thylakoid membrane. In some patients, deposits can also be found within the glomerular basement membrane and between the pedicles of the epithelial cells. In patients with coagulase-positive staphylococcal endocarditis, the deposits are mainly located under the epithelial cells, similar to the presentation of glomerulonephritis after acute streptococcal infection.