Acute poststreptococcal glomerulonephritis
Acute poststreptococcal glomerulonephritis may occur in as part of an epidemic, or following an infection with nephritogenic strains of group A Beta-hemolytic streptococci, 85% of the primary infections are pharyngitis. It more commonly occurs in childhood, however severe adult cases do occur. It is in effect, an acute immune complex disease characterized by the formation of antibodies against streptococci, deposited in the glomeruli.
Clinical presentation is hematuria, proteinuria, hypertension and nephritic syndrome, all occurring about 10 days after a strep infection.
Diagnosis is best with clinical picture and serum antibodies (antistreptolysin O [ASLO], antihyaluronidase [AHT] - note antigens are common in other streptococcal diseases). Biopsy will show little in addition to strep antibody titer and complement level. If used, will show glomeruli are markedly enlarged, filling bowman space with hypercellularity and infiltration of monocytes and proliferation of glomerular cellular elements. Capillary lumens are often compressed with immunoglobulin and C3 depositions.
Kidney biopsy (PAS stain) in post-infectious glomerulonephritis: enlarged, hypercellular glomeruli that fill Bowman's space, surrounded by tubules.
Image: “Post-infectious glomerulonephritis - high mag” by Nephron, CC BY-SA 3.0, via Wikimedia Commons.
Treatment should comprise of the following elements:
- Tackle any remaining strep infection: 10 day phenoxymethylpenicillin
- Increase urine output - restrict salt and monitor fluid inputs
- Decrease hypertension - diuretics and hypotensive medication
In most patients this is a self limiting disease.