Renal pathology 2

Nephritic syndrome
Glomerular diseases presenting with a nephritic syndrome are often characterized by inflammation in the glomeruli.
The nephritic patient usually presents with:
Hematuria.
Red cell casts in the urine.
Azotemia.
Oliguria.
Mild to moderate hypertension.
Proteinuria and edema but these are not as severe as those in the nephrotic syndrome.
Typically, it is characteristic of poststreptococcal glomerulonephritis and crescentic glomerulonephritis.

Poststreptococcal glomerulonephritis

This glomerular disease is a common disorder worldwide.
It usually appears 1 to 4 weeks after a streptococcal infection of the pharynx or skin.
Poststreptococcal glomerulonephritis occurs most frequently in children 6 to 10 years of age, but adults of any age can also be affected.

Etiology and pathogenesis.
Poststreptococcal glomerulonephritis is an immunologically mediated disease.
The latent period between infection and onset of nephritis is compatible with the time required for the production of antibodies and the formation of immune complexes.
Elevated titers of antibodies against streptococcal antigens are present in a great majority of patients. Serum complement levels are low, compatible with activation of the complement system and consumption of complement components.
Clinical Course:
In the classic case, a young child abruptly develops malaise, fever, nausea, oliguria, and hematuria (smoky or cola-colored urine) 1 to 2 weeks after recovery from a sore throat.
The patients have red cell casts in the urine, mild proteinuria (usually less than 1 gm/day), periorbital edema, and mild to moderate hypertension.
More than 95% of affected children eventually recover totally with conservative therapy.

Morphology.
Light microscope:
The changes are diffuse, that is, involving all lobules of all glomeruli, the changes include:

(1) Infiltration by leukocytes, neutrophils and monocytes.
(2) Proliferation of endothelial and mesangial cells.
(3) In severe cases there is crescent formation.
Immunofluorescence microscopy: granular deposits of IgG, IgM, and C3 in the mesangium and along the GBM.
Electron microscopy: discrete, amorphous, electron-dense deposits on the epithelial side of the membrane, often having the appearance of “humps”, subendothelial intramembranous and mesangial deposits may be present.