Nephritic syndrome is defined by hematuria, variable degrees of proteinuria, usually dysmorphic RBCs, and often RBC casts on microscopic examination of urinary sediment. Often ≥ 1 of the following elements are present: edema, hypertension, elevated serum creatinine, and oliguria. It has both primary and secondary causes. Diagnosis is based on history, physical examination, and sometimes renal biopsy. Treatment and prognosis vary by cause.
Nephritic syndrome is a manifestation of glomerular inflammation (glomerulonephritis [GN]) and occurs at any age. Causes differ by age (see Table: Glomerular Disorders by Age and Manifestations), and mechanisms differ by cause. The syndrome can be
Acute (serum creatinine rises over many weeks or less)
Chronic (renal insufficiency may progress over years)
Postinfectious GN is the prototype of acute GN, but the condition may be caused by other glomerulopathies and by systemic disorders such as connective tissue disorders and hematologic dyscrasias (see Table: Causes of Glomerulonephritis).