Glomerulonephritis Overview and Classification

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Questions and Answers

What type of immune complexes are formed in the glomeruli?

Circulating immune complexes

Immune complexes not seen in circulation (correct)

Exogenous immune complexes only

Endogenous immune complexes only

Which of the following accurately describes the location of large immune complexes?

They are dispersed throughout blood circulation.

They are excluded from the GBM and trapped subendothelially. (correct)

They tend to cross the GBM and reside in subepithelial spaces.

They typically accumulate in the mesangium.

In the context of glomerulonephritis, what does 'diffuse' refer to?

Involvement only in select or partial glomeruli.

Involvement of 50% or fewer glomeruli.

Involvement of all glomeruli with complete involvement.

Involvement of 50% or more of the glomeruli. (correct)

What causes proliferation or hypercellularity in the glomerular tuft?

Inflammatory infiltration or increase in glomerular cells. Signup and view all the answers

What characterizes crescent formation in glomerular disease?

Proliferation of parietal epithelial cells and leukocyte infiltration. Signup and view all the answers

Which urinalysis test finding is most likely to be consistently present in patients with periorbital edema?

Proteinuria >3.5 gm/24 hours Signup and view all the answers

What renal lesion is most likely present in a 5-year-old boy with periorbital edema and heavy proteinuria, who improves after corticosteroid therapy?

Podocyte foot process effacement Signup and view all the answers

Which form of glomerular disease is most likely in a 60-year-old man with malaise, pitting edema, and 4+ proteinuria, showing thickening of glomeruli on biopsy?

Membranous nephropathy Signup and view all the answers

In the context of renal disease, what finding is most indicative of chronic kidney damage?

Renal tubular epithelial cells and casts Signup and view all the answers

Which laboratory finding would suggest a possible urinary tract infection in patients with periorbital edema?

Nitrite positive Signup and view all the answers

What is the primary cause of nephrotic syndrome in adults?

Membranous glomerulonephritis Signup and view all the answers

What histological feature is indicative of minimal change glomerulonephritis in electron microscopy?

Effacement of foot processes of podocytes Signup and view all the answers

Which of the following is a common clinical feature of focal segmental glomerulosclerosis?

Massive proteinuria >3.5 g Signup and view all the answers

In the pathogenesis of membranous glomerulonephritis, what type of immune complex is involved?

Insitu immune complex deposits Signup and view all the answers

What does FSGS stand for in terms of renal pathology?

Focal segmental glomerulosclerosis Signup and view all the answers

What is a notable response of minimal change disease to corticosteroid treatment?

Dramatic response Signup and view all the answers

What is the primary characteristic of glomerulonephritis?

It involves lesions that are primarily glomerular. Signup and view all the answers

What is a common age group for the incidence of minimal change disease?

Children aged 2-6 years Signup and view all the answers

Which histological finding is associated with chronic stages of membranous glomerulonephritis?

Total sclerosis of glomeruli Signup and view all the answers

Which type of glomerulonephritis is characterized by heavy proteinuria exceeding 3.5 gm/24h?

Membranous GN Signup and view all the answers

What is a common feature of nephritic syndrome?

Hematuria Signup and view all the answers

Which of the following is NOT classified under primary glomerulopathies?

Diabetes Signup and view all the answers

In the context of glomerular injury, which mechanism involves cytotoxic antibodies?

Antibody-mediated injury Signup and view all the answers

What type of hypersensitivity is associated with circulating immune complex deposition in glomerulonephritis?

Type III hypersensitivity Signup and view all the answers

Which disease is classified under nephritic syndrome?

Goodpasture syndrome Signup and view all the answers

Which of the following statements about nephrotic syndrome is true?

It is characterized by severe generalized edema. Signup and view all the answers

Which classification of glomerulonephritis is based on its duration?

Acute or chronic Signup and view all the answers

What is the predominant mechanism of pathogenesis in primary glomerulonephritis?

Immunological factors Signup and view all the answers

Study Notes

Glomerulonephritis Definition

Glomerular diseases in which the lesions are primarily in the glomeruli
It is characterized by inflammation
Absence of typical inflammation features

Glomerulonephritis Classification

Classified according to cause, clinical presentation and duration
Cause:
- Primary glomerulopathy: Intrinsic or unknown cause
- Secondary glomerulopathy: Resulting from other systemic diseases or conditions
Clinical Presentation:
- Nephrotic syndrome: Massive proteinuria (>3.5 gm/24h), hypoalbuminemia (<3 gm), generalized edema, hyperlipidemia and lipiduria
- Nephritic syndrome: Hematuria, mild to moderate proteinuria, hypertension, oliguria, uremia, chronic renal failure
- Mixed: Features of both nephrotic and nephritic syndrome
Duration:
- Acute glomerulonephritis: Rapid onset, often with a specific trigger
- Chronic glomerulonephritis: A long-term process, with gradual decline in kidney function

### Glomerulonephritis Specific Conditions

Nephritic Syndrome: Diffuse proliferative glomerulonephritis, rapidly progressive glomerulonephritis (crescentic), Goodpasture syndrome, focal glomerulonephritis, Primary Berger's disease (IgA nephritis), Secondary IgA nephritis, Henoch-Schonlein purpura, Subacute bacterial endocarditis (SBE)
Nephrotic Syndrome: Membranous glomerulonephritis, minimal changes glomerulonephritis, focal segmental glomerulosclerosis (FSGS), membranoproliferative glomerulonephritis, IgA nephropathy, secondary to systemic disease

Glomerulonephritis Pathogenesis

Genetic: Congenital nephrotic syndrome
Acquired:
- Immunological: Most forms of primary glomerulonephritis
- Non-immunological: Other factors such as drugs or toxins

Immune Mechanisms of Glomerular Injury

Antibody-mediated injury:
- In situ immune complex deposition: Fixed tissue antigens, planted antigens
- Circulating immune complex deposition: Exogenous or endogenous antigens
- Cytotoxic antibodies
Cell-mediated immune injury: T-cell mediated
Activation of the alternative complement pathway: Independent of specific antibodies

Antibody-Mediated Injury

Cytotoxic Antibodies (Antibodies to Glomerular Cells): Antibodies against glomerular cell antigens react with cellular components and cause injury by Type II hypersensitivity
- Antibodies to mesangial cell antigens: Mesangial cell proliferation
- Antibodies to endothelial cell antigens: Endothelial injury and intravascular thrombosis
- Antibodies to certain visceral epithelial cell proteins: Proteinuria
Circulating Immune Complexes: Trapping of circulating antigen-antibody complexes within glomeruli (Type III hypersensitivity)
- Endogenous: RNA antigen, tumor antigen, unknown
- Exogenous: HBV, Streptococci, malaria, syphilis
- Site of deposition depends on size and molecular charges
  - Small complexes tend to cross the GBM and reside subepithelially
  - Large complexes are excluded from the GBM and trapped subendothelially
  - Neutral charge complexes accumulate in the mesangium
In situ Immune Complexes: Not seen in the circulation but formed within the glomeruli
- Fixed intrinsic tissue antigen: Examples include the capillary basement membrane (Goodpasture syndrome)
- Planted antigen: Antibodies react in situ with antigens not normally present in the glomerulus, but are "planted" there (e.g., bacteria)

### Histological Alterations and Descriptive Terms in Glomerulonephritis

All Glomeruli:
- Diffuse: Involvement of ≥50% of the glomeruli
- Focal: Involvement of ≤50% of the glomeruli
Individual Glomerulus:
- Global: If all or almost all of the glomerulus is affected
- Segmental: If only part of the glomerulus is affected
Proliferation (Hypercellularity): Increase in the number of cells in the glomerular tuft
Crescent formation (Partial epithelial proliferation): Accumulations of cells composed of proliferating parietal epithelial cells and infiltrating leukocytes
Basement Membrane Thickening: Normal basement membrane structure is altered
Sclerosis: Extracellular material deposition in the glomerulus similar in composition to the GBM and mesangial matrix
Fibrosis: Deposition of collagen type I and III

### Nephrotic Syndrome

Membranous glomerulonephritis (MGN): Major cause of nephrotic syndrome in adults, common in middle and old age, men > women
Minimal Changes Glomerulonephritis (Lipoid Nephrosis): Major cause of nephrotic syndrome in children, common in 2-6 year olds
Focal Segmental Glomerulosclerosis (FSGS): 80% present with nephrotic syndrome, focal = sclerosis of some glomeruli, not all, segmental = portion of the capillary tuft is affected
Membranoproliferative glomerulonephritis: Features both nephrotic and nephritic syndrome

Membranous Glomerulonephritis

Incidence: Major cause of nephrotic syndrome in adults, common in middle and old age, men > women
Pathogenesis: In situ immune complex (IgG) along the wall of the glomeruli
- Primary: 85%, unknown antigen
- Secondary: Malignant tumor, drugs, infection
Pathology:
- Light Microscopy: The glomeruli are more or less normal in size in early stages with no cellular infiltration or proliferation. Later stages show hyaline thickening in the glomerular basement membrane.
- Silver Stain: Thickening of the basement membrane with spikes.
- Electron Microscopy: Subepithelial irregular deposit of dense material in the basement membrane, thickening of the basement membrane, spikes in the basement membrane, effacement of podocytes, narrowing of capillary lumen leading to occlusion, hyalinization, atrophy of tubules and interstitial fibrosis in chronic stages

Minimal Changes Glomerulonephritis

Incidence: Major cause of nephrotic syndrome in children, common in 2-6 year olds
Pathogenesis: No immune deposits in the glomeruli, but an immunological basis is suggested
Pathology:
- Light Microscopy: The glomeruli are more or less normal
- Electron Microscopy: Effacement of foot processes of podocytes replaced by a rim of cytoplasm with vacuolation. Proximal convoluted tubules are lipid-laden due to absorption of lipoproteins
Clinical Course: Massive proteinuria (>3.5 gm, highly selective to albumin), renal function is normal, no hypertension or hematuria, dramatic response to corticosteroids, excellent prognosis

Focal Segmental Glomerulosclerosis

Incidence: 80% present with nephrotic syndrome.
Pathology:
- Light Microscopy: Sclerotic segments demonstrate collapsed basement membrane, increased mesangial matrix, hyalinization. Non-sclerotic segments appear more or less normal.
- Electron Microscopy: Diffuse effacement of foot processes, focal detachment of epithelial cells, denudation of basement membrane.
Fate: Total sclerosis of glomeruli, tubular atrophy, interstitial fibrosis, chronic renal failure (CRF)

References

https://www.clinicalkey.com/student/content/book/3-s2.0-B9780323531139000200#hl0001821
https://www.clinicalkey.com/student/content/book/3-s2.0-B9780323531139000200#hl0001896
https://www.clinicalkey.com/student/content/book/3-s2.0-B9780323531139000200#hl0002217

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Description

This quiz explores the definition and classification of glomerulonephritis, a type of kidney disease. Participants will learn about its causes, clinical presentations, and the differences between acute and chronic forms. This knowledge is essential for understanding kidney health and disease management.