[Primary glomerulonephritides]

Primary glomerulonephritides are inflammatory diseases primarily targeting the glomeruli. Clinically, patients may present with glomerular hematuria and a nephritic urinary sediment and/or with high levels of proteinuria and nephrotic syndrome. Arterial hypertension is also frequently observed in these patients. Although these diseases often lead to loss of renal function, clinical symptoms may be very mild, or even absent in the early stages. Early diagnosis and timely initiation of therapy are therefore of paramount importance. Urinalysis for the detection of glomerular hematuria (by means of urine dipstick and urinary sediment) and proteinuria represents a simple yet highly relevant diagnostic tool for the identification of affected patients. Therefore, such screening procedures should be performed whenever even a minimal suspicion of glomerular disease exists. Although all primary glomerulonephritides primarily affect the glomeruli, the pathogenesis of the various entities-IgA nephropathy, membranous nephropathy, minimal change disease, and primary focal and segmental glomerulosclerosis-differs substantially. Moreover, considerable interindividual variability in disease course and prognosis is observed even within the same diagnostic entity. Therefore, the decision of whether and when to initiate immunosuppressive therapy needs to be individualized, taking into account the risk of disease progression and prognosis. Due to the significant differences in pathogenesis, progression risk, and prognosis between the different forms of glomerulonephritis, as well as within each disease entity, and given the complexity of treatment strategies, patients with primary glomerulonephritis require specialized care in centers with experience in the treatment of these diseases. In recent years, major advances have been made in elucidating the pathomechanisms of primary glomerulonephritides, leading to significant improvements in diagnostic and therapeutic options. Nonetheless, early diagnosis remains a central objective in order to enable targeted and effective treatment and to improve long-term renal outcomes.