Post-streptococcal Glomerulonephritis (PSGN) (Study Outline)…
Post-streptococcal Glomerulonephritis (PSGN) (Study Outline) 1. Background Definition: Immune-mediated nephritic glomerular disease occurring after infection with group A β-hemolytic Streptococcus (pharyngitis or impetigo). Pathophysiology: Immune complex deposition in glomeruli → complement activation (classical pathway) → inflammation → ↓ GFR. Epidemiology: Most common in children (5–12 years), but can occur in adults with more severe disease course. Timing: Pharyngitis: GN develops 1–2 weeks after infection. Impetigo: GN develops 3–6 weeks after infection. Key concept: A post-infectious immune response, not direct bacterial invasion. 2. History Tea- or cola-colored urine (gross hematuria). Recent strep infection: sore throat, fever, impetigo. Oliguria or decreased urine output. Edema: especially periorbital in the morning. Hypertension due to fluid retention. Constitutional symptoms: malaise, mild fever. Adults may report more severe symptoms or signs of volume overload. 3. Exam Findings Vital signs: hypertension is common. Edema: periorbital and peripheral. Signs of fluid overload: crackles, elevated JVP (severe cases). Skin findings: impetigo lesions if recent skin infection. Generally nephritic pattern: less proteinuria than nephrotic syndromes. 4. Making the Diagnosis Urinalysis: Hematuria with RBC casts (key nephritic hallmark). Mild–moderate proteinuria (