Glomerulonephritides associated with infections constitute an important group of diseases. Their occurrence is shifting from children and young people to elderly people.
The rates of acute post-streptococcal glomerulonephritis, a condition with a good prognosis, are decreasing, and the rates of glomerulonephritides associated with various bacterial, viral, or parasitic infections, often with a poor prognosis, are increasing. Renal biopsy plays an important role in the diagnostic process.
Manifestations of glomerulonephritis can be the initial sign of an occult infection. When evaluating renal biopsy specimens, certain signs may suggest this option, but it cannot be relied on completely.
The search for an active infection is warranted in every patient with newly diagnosed glomerulonephritis. Hepatitis B and C serology is always performed, with other investiga- tions depending on individual risk factors, clinical manifestations, and laboratory and histological findings.
Failure to follow this rule may have serious consequences, in part because immunosuppressive therapy for glomerulonephritis can worsen the underlying infection and also because the progressive nature of parainfective glomerulonephritis cannot be reversed without eliminating the causative infection. Distinguishing between parainfective and autoimmune glomerulonephritis can be difficult, as there are no major differences in clinical manifestations, laboratory, and sometimes even histological findings.
In the setting of the Czech Republic, important diseases include, in particular, staphylococcus infection-associated glomerulonephritis (SAGN) and, in general, infective endocarditis-associated glomerulonephritis, shunt nephritis, and other cases associated with foreign-material infection, such as catheters or electrodes. Among viral diseases, glomerulonephritides associated with the hepatitis B virus, hepatitis C virus, and the SARS CoV-2 virus are of major significance.
The treatment of parainfectious glomerulonephritides involves elimination of the causative infection; only in rare cases, a combination of anti-infective treatment and mild immunosuppression can be indicated.