Glomerulonephritis (GN) encompasses a heterogeneous group of disease processes. It accounts for approximately 20% of chronic kidney disease and is the second most common cause of kidney failure worldwide. A study of a cohort of Medicare patients found that approximately 1.2% were affected. GN should be suspected in patients with unexplained hematuria, particularly with persistent hematuria with red blood cell casts and/or acanthocytes, and proteinuria. Other presenting features include purpura (in children) and hypertension. When GN is suspected based on test results, patients should be referred to a nephrologist for further evaluation and consideration of kidney biopsy, which is the gold standard diagnostic test. GN is categorized as acute (sudden onset of hematuria and proteinuria) or chronic (with irreversible scarring on biopsy). Acute GN is more likely to be reversible. Initial management consists of supportive and protective measures, including blood pressure control, drugs to block the renin-angiotensin system, and lifestyle modifications to minimize cardiovascular risk. The underlying cause should be treated when possible. Subsequent management depends on the specific type of GN and might include antimicrobial therapy and/or immunosuppressive therapy when appropriate.

Case 1. RZ is a 27-year-old patient who comes to your office with a 2-day history of a sore throat and fever of 38 °C (100.4 °F). The physical examination is notable for hypertension, oropharyngeal erythema, and minimal cervical lymphadenopathy. A rapid streptococcal antigen test has a positive result and a urinalysis dipstick result shows 3+ blood and 1+ protein.