poststreptoccal glomerulonephritis

Poststreptococcal Glomerulonephritis

Nirav Dhruva

Morning Report

July 2005

Poststreptococcal GN (Introduction) Usually occurs 10 days

after pharyngitis and 14 days after skin infection

(not synpharyngitic) Fallen incidence in US,

but common in some rural areas, poor hygiene places, and tropical countries

Occurs more often in males and children

Poststreptoccal GN (nephritic strains)

Known nephritic strains include M types 1, 2, 4, 12, 18, 25, 49, 55, 57, 60

Many proposed mechanisms: Molecular mimickry vs. autoimmune vs. polyclonal activation of B lymphocytes

Repeat infections are not common as immunity is type specific and not usually transient

Clinical Presentation Most patients have milder disease Classically, presents with overt nephritic

syndrome and oliguric ARF Symptoms can include gross hematuria

(100% microscopic), HA, htn (60-80%), hypervolemia, and edema (80-90%)

Clinical Presentation Nephritic urinary

sediment – dysmorphic RBCs, red cell casts, leukocytes, subnephrotic proteinuria

Nephrotic-range proteinuria not common

Labs

Serum Cr can be commonly elevated at presentation, though mild

C3 and CH50 decreased w/in 2 weeks C4 usually normal (complement level usually normal within 6-

8 weeks) Most patients have directed Ab, such as ASO, anti-DNAse B,

etc Serum IgG and IgM increased in 80% and returns to normal

in 1-2 months Polyclonal cryoglobulinemia in 75%

Light MicroscopyOn light microscopy,

usually see diffuse proliferative GN

Immunofluorescence Microscopy Deposition of IgG and

C3

3 patterns

mesangialStarry sky (mesangial

and capillary wall)Garland (capillary loops)

Electron Microscopy large electron – dense

immune deposits in subendothelial, subepithelial, and mesangial areas

Course Irreversible Renal Failure rare – less than 1 % in

children, slightly higher in adults Resolution usually quick, plasma Cr usually

returns to previous levels by 3-4 weeks Hematuria resolves usually within 3-6 months,

proteinuria falls at a slower rate Some patients experience htn, recurrent

proteinuria, and renal insufficiency 10-40 yrs after > 20% of adults may have some degree of

persistent proteinuria and or compromise of GFR 1 year out

Treatment Eliminate strep infxn with abx Supportive therapy Diuretics and antihypertensives to control

bp and extracellular fluid volume

Acute GN and Pulmonary Hemorrhage ANCA associated systemic vasculitis and anti-

GBM - common causes Also reported to occur in SLE, HSP, mixed

Cryoglobulinemia Study of 88 patients with Pulmonary Hemorrhage

and Nephritis: 48 ANCA, 6 Anti GBM, 7 both, 27 neither ANCA nor anti-GBM (latter group – not many causes could explain both findings)

The End

References Rose, Burton. “Acute Glomerulonephritis and Pulmonary

Hemorrhage, “Course of Poststreptococcal Glomerulonephritis. Up To Date 2005.

Harrison’s Online. Glomerular Disease. Ch 264. 2004-2005. Niles JL, et al. The Syndrome of Lung Hemorrhage and Nephritis

is Usually an ANCA – Associated Condition. Arch Intern Med. 1996; 156: 440-445.

Gallagher H, et al. Pulmonary Renal Syndrome: A 4 Year, Single-Center Experience. Am J of Kidney Disease 2002; 39: 42-47.

Berrrios X, et al. Post-streptococcal Acute Glomerulonephritis in Chile – 20 Years of Experience. Pediatr Nephrol 2004; 19: 306-312.

Johnson RJ, et al. Glomerular Disease Associated with Infection. Ch 30. Comprehensive Clinical Nephrology. 2000.