Minimal change glomerulopathy

Kidney nontumor
Primary glomerular diseases
Minimal change glomerulopathy

Author: Nikhil Sangle, M.D. (see Authors page)

Revised: 11 July 2018, last major update March 2014

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Minimal change glomerulopathy [title]

Table of Contents

Cite this page: Sangle, N. Minimal change glomerulopathy. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneyminchange.html. Accessed October 23rd, 2018.

Definition / general

Also called minimal change disease, nil disease, lipoid nephrosis and foot process disease
Causes 80% of cases of nephrotic syndrome in children (usually ages 2 - 6), 20% in adults

Pathophysiology

Extensive foot process "fusion" appears to be due to epithelial injury with loss of glomerular anionic charge
Overproduction of angiopoietin-like 4 (ANGPTL4) in podocytes causes it to bind to glomerular basement membrane, leading to selective proteinuria, diffuse effacement of foot processes and loss of glomerular basement membrane charge (Am J Kidney Dis 2012;59:284, Nat Med 2011;17:117); due in part to sialic acid residue deficency in ANGPTL4 (oral supplementation with sialic acid precursor N-acetyl-d-mannosamine improves sialylation of podocyte-secreted ANGPTL4 and significantly decreases proteinuria)
"Fusion" is actually simplification of epithelial architecture with flattening, retraction and swelling of foot processes; also seen in membranous glomerulopathy and diabetes; reverts to normal with remission

Diagrams / tables

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Lipoid nephrosis

Clinical features

Nephrotic syndrome, proteinuria selective for albumin, causing hypoalbuminemia leading to severe edema
Elevated serum cholesterol, but with minimal microscopic glomerular alterations and usually no hypertension, no hematuria and no azotemia
Note: minimal change disease, diffuse mesangial hypercellularity and focal and segmental glomerulosclerosis may be a continuum of the same disease
Associated with respiratory infections, immunizations, lead or mercury ingestion, allergies, acute interstitial nephritis and Hodgkin’s lymphoma; in elderly, associated with NSAIDs

Case reports

Intravascular B cell lymphoma of kidney associated with minimal change disease (Hum Pathol 1989;20:263)

Treatment

90% of children respond to steroids initially (foot processes return to normal), may require immunosuppression, < 5% develop renal failure after 25 years
Some children become steroid dependent / resistant, but this usually resolves at puberty
Older adults with hypertension and severe proteinuria have a higher risk of reversible renal failure
Rituximab may be effective in adults (Clin Nephrol 2011;76:151)
May develop nephrocalcinosis due to hypercalciuria from chronic furosemide use (Hum Pathol 2000;31:1363)

Microscopic (histologic) description

Normal glomeruli, tubules have lipid droplets due to reabsorption of lipoproteins that leak from glomeruli ("lipoid nephrosis")

Microscopic (histologic) images

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Relatively normal
appearing glomeruli
and lipoid nephrosis

Immunofluorescence

Generally negative
May show weak nonspecific IgM in mesangial distribution, but no deposits in GBM
Albumin in proximal tubular epithelial cells

Electron microscopy description

Extensive foot process effacement (foot processes retract into cell bodies, not actually fusion)
Microvillous transformation of epithelial cells, cyst formation

Electron microscopy images

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Foot process effacement

Differential diagnosis

Focal and segmental glomerulosclerosis: tubular atrophy and interstitial scarring; global glomerular sclerosis may be present in minimal change disease if there is underlying arterionephrosclerosis; minimal change disease may also be associated / superimposed on other conditions such as IgA nephropathy