- Nephritic Syndrome is a clinical syndrome that can be initiated by a number of distinct etiologies that lead to a shared pathogenic sequence.
- Nephritic syndrome is characterized by hematuria and pyuria, often with the presence of erythrocyte casts within the urine. Patients also display hypertension, azotemia, and oliguria. In contrast to nephrotic syndrome, proteinuria and generalized edema are less pronounced or non-existent in those with nephritic syndrome.
- Primary Defect: Glomerular Inflammation
- The primary insult in nephritic syndromes appears to be initiation of inflammation in the glomeruli. Inflammation likely injures the glomerular capillaries, allowing for escape of erythrocytes and leukocytes in the urine, thus yielding hematuria and pyuria. Extruded erythrocytes may aggregate in the tubule and thus take its shape, resulting in characteristic "erythrocyte casts" within the urine.
- Secondary Defect: Reduced GFR
- Progressive damage to involved glomeruli results in a decline in the overall Glomerular Filtration Rate (GFR) that yields the other pathophysiological sequelae. Reductions in GFR reduce capacity for urine formation, causing oliguria, as well reduce the clearance of metabolites, causing azotemia. Deficient GFR also reduces the capacity of the kidneys to properly control mechanisms of long-term arterial pressure regulation, yielding secondary hypertension.