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Most Frequent Clinical

Presentation Pathogenesis Light Microscopy Fluorescence Microscopy Electron Microscopy

Poststreptococcal

glomerulonephritis

Acute nephritis Antibody mediated;

circulating or planted antigen

Diffuse proliferation;

leukocytic infiltration

Granular IgG and C3 in GBM

and mesangium

Subepithelial humps

Goodpasture syndrome Rapidly progressive

glomerulonephritis

Anti-GBM COL4-A3 antigen Proliferation; crescents Linear IgG and C3; fibrin in

crescents

No deposits; GBM

disruptions; fibrin

Idiopathic RPGN Rapidly progressive

glomerulonephritis

Anti-GBM antibody Proliferation; focal necrosis;

crescents

Linear IgG and C3 No deposits

Immune complex Granular IgG or IgA or IgM Deposits may be present

ANCA-associated Negative or equivocal No deposits

Membranous glomerulopathy Nephrotic syndrome In situ antibody-mediated;

antigen unknown

Diffuse capillary wall

thickening

Granular IgG and C3; diffuse Subepithelial deposits

Minimal change disease Nephrotic syndrome Unknown, loss of

glomerular polyanion;

podocyte injury

Normal; lipid in tubules Negative Loss of foot processes; no

deposits

Focal segmental

glomerulosclerosis

Nephrotic syndrome;

non-nephrotic proteinuria

Unknown, Ablation

nephropathy Plasma factor

(?); podocyte injury

Focal and segmental

sclerosis and hyalinosis

Focal; IgM and C3 Loss of foot processes;

epithelial denudation

Membranoproliferative

glomerulonephritis (MPGN)

Type I

Nephrotic syndrome (I) Immune complex (I) IgG + C3; C1q + C4 (I) Subendothelial deposits

Mesangial proliferation;

basement membrane

thickening; splitting

Dense deposit disease (MPGN

Type II)

Hematuria (II) Autoantibody:

alternative complement

pathway

(II) C3 IgG; no C1q or C4 (II) Dense deposits

Chronic renal failure

IgA nephropathy Recurrent hematuria or

proteinuria

Unknown; see text Focal proliferative

glomerulonephritis;

mesangial widening

IgA +/- IgG, IgM, and C3 in

mesangium

Mesangial and

paramesangial dense deposits

Chronic glomerulonephritis Chronic renal failure Variable Hyalinized glomeruli Granular or negative

ANCA, antineutrophil cytoplasmic antibody; GBM, glomerular basement membrane; RPGN, rapidly progressive glomerulonephritis.

all lobules of all glomeruli. There is also swelling of endothelial cells, and the combination of proliferation, swelling, and leukocyte infiltration obliterates the capillary lumens. There may

be interstitial edema and inflammation, and the tubules often contain red cell casts.

By immunofluorescence microscopy,there are granular deposits of IgG, IgM, and C3 in the mesangium and along the basement membrane. Although almost universally present, they are

often focal and sparse. The characteristic electron microscopic findingsare discrete, amorphous, electrondense deposits on the epithelial side of the membrane, often having the

appearance of "humps" ( Fig. 20-16C) , presumably representing the antigen-antibody complexes at the epithelial cell surface. Subendothelial and intramembranous deposits are also



commonly seen, and mesangial deposits may be present. There is often swelling of endothelial and mesangial cells.

Clinical Course.

In the classic case, a young child abruptly develops malaise, fever, nausea, oliguria, and hematuria (smoky or cocoa-colored urine) 1 to 2 weeks after recovery from a sore throat. The

patients exhibit red cell casts in the urine, mild proteinuria (usually less than 1 mg/day), periorbital edema, and mild to moderate hypertension. In adults, the onset is more likely to be

atypical, with the sudden appearance of hypertension or edema, frequently with elevation of BUN. During epidemics caused by nephritogenic streptococcal infections, glomerulonephritis

may be asymptomatic, discovered only on screening for microscopic hematuria. Important laboratory findings include elevations of antistreptococcal antibody (ASO) titers and a decline in

the serum concentration of C3 and other components of the complement cascade and the presence of cryoglobulins in the serum.

More than 95% of affected children eventually recover totally with conservative therapy aimed at maintaining sodium and water balance. A small minority of children (perhaps less than

1%) do not improve, become severely oliguric, and develop a rapidly progressive form of glomerulonephritis

Figure 20-16Acute proliferative glomerulonephritis. A, Normal glomerulus. B, Glomerular hypercellularity is due to intracapillary leukocytes and proliferation of intrinsic glomerular

cells. C, Typical electron-dense subepithelial "hump" and a neutrophil in the lumen. (Courtesy of Dr. H. Rennke, Brigham and Women's Hospital, Boston, MA.)

TABLE 20-7-- Rapidly Progressive Glomerulonephritis (RPGN)


Date: 2016-04-22; view: 380


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