Poststreptococcal Glomerulonephritis

Occurs following GAS pharyngitis OR skin/soft tissue infections, due to immune complex deposition  in the kidneys, leading to complement activation and inflammation.

Ranges from asymptomatic microscopic hematuria to full-blown nephritic syndrome (red/brown urine, proteinuria, edema, HTN, renal failure).

Dx: UA showed hematuria, often with dysmorphic RBCs +/- RBC casts, +/- proteinuria and pyuria.
Significantly decreased C3, C4 is actually often normal or only slightly decreased.
Throat or skin cultures are positive <25% of the time, due to the latent period.  Serologies for evidence of recent strep infection can be helpful: Anti-streptolysin Abs, for example.

There is no specific treatment, including immunosuppressive meds, and management is supportive – volume control with Na/H20 restriction +/- diuretics, and PCN if evidence of continued strep infection.  Prognosis is excellent and renal function often returns to normal within several weeks-months.

(Chanu Rhee MD, 10/19/10)