Fogo, Ch. 5 - Postinfectious glomerulonephritis

Question 1

What organisms cause post-infectious glomerulonephritis?

Answer 1

Clasically group A strep, but also fungi, viruses, and other bacteria.

Question 2

What is the clinical presentation of postinfectious glomerulonephritis?

Answer 2

Nephritic pattern with edema (from sodium retention), elevated ASO usually, decreased complement. Urine sediment with RBC casts.

Question 3

What is the pathophysiology of postinfectious glomerulonephritis?

Answer 3

Strep pyogenic (or other) exotoxins form complexes with antibodies which deposit in glomeruli.

Question 4

What is the outlook of postinfectious glomerulonephritis?

Answer 4

Generally good, though some will retain subclinical sequelae. Adults and diabetics fare worse, as do those with bad proteinuria.

Question 5

What are the glomerular LM findings in postinfectious glomerulonephritis?

Answer 5

Diffuse dilation and endocapillary hypercellularity without necrosis. Inflammatory infiltrate and subepithelial humps.

Question 6

What are the tubulointerstitial LM findings in postinfectious glomerulonephritis?

Answer 6

Protein reabsorption droplets, edema, erythrocytes and neutrophils. Should not see vessel disease.

Question 7

What are the IF findings in postinfectious glomerulonephritis?

Answer 7

Coarse granular IgG/C3 along capillary walls. Maybe IgM/IgA, but not C1q.

Question 8

In which cases is IgA deposition more often seen in postinfectious glomerulonephritis?

Answer 8

WIth staph infection, in older and diabetic patients.

Question 9

What are the EM findings in postinfectious glomerulonephritis?

Answer 9

Endothelial swelling and mesangial hypercellularity with subepithelial humps.

Question 10

Which modality is most useful to diagnose postinfectious glomerulonephritis?

Answer 10

Light microscopy (again, look for endocapillary hypercellularity and mixed infiltrate).