Advertisement
Advertisement
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Diagrams / tables | Clinical features | Diagnosis | Laboratory | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Immunofluorescence description | Electron microscopy description | Electron microscopy images | Molecular / cytogenetics description | Differential diagnosis | Additional references | Board review question #1 | Board review answer #1 | Board review question #2 | Board review answer #2 | Board review question #3 | Board review answer #3Cite this page: Larqué AB. Minimal change glomerulopathy. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneyminchange.html. Accessed March 23rd, 2019.
Definition / general
- Idiopathic glomerular disease that causes nephrotic syndrome
- Little or no light or immunofluorescent microscopic abnormalities
- Diffuse foot process effacement on electron microscopy (BMC Nephrol 2018;19:207)
Essential features
- Renal glomeruli appear normal by light and immunofluorescence microscopy
- Extensive effacement of podocyte foot processes by electron microscopy (hallmark)
- Highly selective proteinuria, mainly albuminuria
- Responds well to treatment with corticosteroids (90 - 95%)
Terminology
- Also called minimal change disease, idiopathic nephrotic syndrome, nil disease, lipoid nephrosis and foot process disease
ICD coding
Epidemiology
- Most common type of nephrotic syndrome in children: 70 - 90%; in adults: 11 - 16%
- Peak incidence in children: 2 - 3 years; in adults: 80 - 91 years
- In children, M:F = 2:1; in adults, M = F
- More common in Caucasians and Asians than African-Americans (Clin J Am Soc Nephrol 2007;2:445)
Sites
- Glomerular disease
Pathophysiology
- Extensive foot process "fusion" appears to be due to epithelial injury with loss of glomerular anionic charge (Kidney Int 1984;25:696)
- Unknown circulating factor that triggers podocyte dysfunction postulated (Pediatr Nephrol 2018;33:1101)
- Minimal change disease, diffuse mesangial hypercellularity and focal segmental glomerulosclerosis may be a continuum of the same disease (Kidney Int 2004;65:1690)
Etiology
- Usually idiopathic, especially in children (Clin J Am Soc Nephrol 2017;12:332)
- Secondary forms due to virus, drugs, allergic reactions, immunologic diseases and neoplasia at all ages (BMC Nephrol 2018;19:162, Intern Med 2014;53:1131, Case Rep Nephrol 2015;2015:987212, J Surg Oncol 2010;102:704)
- Rarely familial (gene mutations: NPHS2, dysferlin) (Semin Nephrol 2003;23:141)
Diagrams / tables
Images hosted on other servers:
Lipoid nephrosis
Clinical features
- Nephrotic syndrome
- Proteinuria selective for albumin, causing hypoalbuminemia leading to severe edema
- Lipiduria, hypercholesterolemia but usually no hypertension, no hematuria and no azotemia
- Microhematuria (10 - 30%)
- Can present as acute renal insufficiency in adults (Clin J Am Soc Nephrol 2017;12:332)
Diagnosis
- Nephrotic syndrome with little or no light or immunofluorescent microscopic abnormalities
- Diffuse foot process effacement on electron microscopy
Laboratory
- CD80 in urine may be a marker (Pediatr Nephrol 2015;30:309)
Prognostic factors
- Rarely, if ever, leads to end stage renal disease without development of focal segmental glomerulosclerosis
- Adults with minimal change disease and acute renal failure also usually fully recover (Medicine (Baltimore) 2014;93:e300)
- Relapses common and often lead to steroid dependence
Case reports
- 2 and 15 year old boys with steroid responsive nephrotic syndrome complicated by cerebral venous sinus thrombosis (Nefrologia 2015;35:497)
- 29 year old woman with type I neurofibromatosis and complete remission after neurofibroma resection (Korean J Intern Med 2017;32:186)
- 33 year old man with severe chronic sinusitis (Intern Med 2015;54:2373)
- 50 year old woman with minimal change disease after a type B influenza infection (BMC Nephrol 2018;19:162)
- 68 year old man with marginal zone MALT lymphoma manifesting as nephrotic range proteinuria (Clin Nephrol 2016;85:184)
Treatment
- Corticosteroids
- Immunosuppressive agents in steroid resistant cases (cyclophosphamide, rituximab, abatacept) (Kidney Int 2013;83:511, Pediatr Nephrol 2015;30:469)
Gross description
- Enlarged, waxy yellow cortex due to lipid accumulation in proximal tubules
Microscopic (histologic) description
- Glomerulus normal by light microscopy except for variable podocyte hypertrophy
- Protein reabsorption droplets in tubules (Zhou: Silva's Diagnostic Renal Pathology, 2nd Edition, 2017)
Microscopic (histologic) images
Contributed by Ana Belén Larqué, M.D., Ph.D.
Aggregates of lipid laden macrophages
Images hosted on other servers:
Relatively normal
appearing glomeruli
and lipoid nephrosis
Immunofluorescence description
- Negative except for variable focal IgM ± C3
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
Contributed by Ana Belén Larqué, M.D., Ph.D.
Hypertrophic podocytes
Images hosted on other servers:
Foot process effacement
Molecular / cytogenetics description
- Rarely familial (Semin Nephrol 2003;23:141, Hum Mol Genet 1995;4:2155, J Am Soc Nephrol 2002;13:388)
- Histologic findings of focal segmental glomerulosclerosis or more rarely minimal change glomerulopathy are a part of the autosomal recessive steroid resistant nephrotic syndrome
- Mutations in NPHS2 have been detected in both familial and sporadic steroid resistant nephrotic syndrome
- NPHS2 gene, formerly SRN1, encodes podocin, a protein that is almost exclusively expressed in glomerular podocytes
Differential diagnosis
- Focal segmental glomerulosclerosis:
- Segmental hyalinosis or synechiae to Bowman capsule, interstitial fibrosis or tubular atrophy
- Cases with unsampled glomerulosclerosis may be misdiagnosed as minimal change disease
- Mesangial glomerulonephritis:
- Early mesangial glomerulonephritis can be indistinguishable on light microscopy
- Positive immunofluorescence and electron dense subepithelial deposits on electron microscopy
- Chyluria:
- Normal podocytes with heavy proteinuria
- IgA nephropathy:
- Minimal change disease could be superimposed on IgA nephropathy
Additional references
Board review question #1
Which of the following is true about minimal change glomerulopathy?
- Interstitial inflammation and fibrosis are usually absent
- It is the most common type of nephrotic syndrome in adults
- Monoclonal antibody therapy should be the first line therapy
- Pretreatment biopsy is always done
Board review answer #1
Board review question #2
Which of the following signs and symptoms is common in minimal change disease?
- Azotemia
- Hypertension
- Macrohematuria
- Selective proteinuria
Board review answer #2
Board review question #3
Which of the following renal lesions is most likely to be present in minimal change disease?
- Acute tubular necrosis
- Glomerular crescent formation
- Mesangial immune complex deposition
- Podocyte foot process effacement
Board review answer #3
