CVPR Week 8: Renal diseases Part A Flashcards
Glomerular diseases
- Minimal change disease
- Focal segmental glomerulosclerosis
- Membranous nephropathy
- Mesangio-proliferative GN
- Membrano-proliferative GN (MPGN)
- Proliferative GN
GN AKA
Glomerulonephritis
Renal biopsy for glomerular diseases is assessed by?

Stains for light microscopy renal biopsies

Patterns of glomerular injury as seen through PAS

What is the purpose of immunofluorescence microscopy in renal disease
To check for abnormal immune deposits in a patient’s glomerulus
Such as IgG, IgA, IgM, C3, C1q, kappa, lambda
and in what kind of pattern is it granular or linear
Identify


Features of nephrotic syndrome
- Massive proteinuria - Loss of >=3.5 g of protein per day
- Hypalbuminuria - plasma albumin levels <3 g/dL
- Generalized edema
- Hyperlipidemia and lipiduria
- typically insidious onset
Nephrotic syndrome onset
insidious onset
Membranous nephropathy etiology
- Primary - ~75% of cases are idiopathic
- Secondary - associated with systemic diseases
Systemic diseases that can lead to membranous nephropathy
- Systemic lupus erythematosus
- Infections (chronic hepatitis B and C
- Malignancies (lung, colon and melanoma)
- Drugs (penicillamine, captopril, gold and NSAIDs
Membranous nephropathy onset
Insidious onset of nephrotic syndrome
Membranous nephropathy clinical course
- proteinuria persists in >60% of cases
- 10% progress to renal failure in 10 years
- <40% develop severe chronic kidney disease
Membranous nephropathy considerations
Doesn’t respond well to steroids
Pathogenesis of autoimmune membranous nephropathy
- Linked to certain HLA alleles (HLA DQA1)
- Autoantigen is phospholipase A2 receptor (PA2R)
Pathogenesis of immune-complex-mediated disease of membranous nephropathy
- Activation of complement
- Production of proteases and oxidants
- Causes capillary wall injury and protein leakage
Pathogenesis of secondary disease of membranous nephropathy
- Antigens from infectious microbes (e.g. hepatitis B virus) from immune complexes
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Membranous nephropathy features on light microscopy
- Uniform thickening of glomerular capillary wall
- Spikes on Jones silver stain (are basement membrane material)
Membranous nephropathy features on immunofluorescence microscopy
Granular deposits of immunoglobulins and complement
Membranous nephropathy features on electron microscopy
- Subepithelial electron dense deposits (between GBM and podocytes)
- Spikes
- Podocyte foot process effacement
IgA nephropathy AKA
Mesangio-proliferative GN
Types of proliferative GN
Post streptococcal GN
Pauci-immune GN (ANCA disease)
Anti-GBM GN
What is hematuria?
red blood cellls in urine
Azotemia =
- decreased GFR
- but increased creatinine and BUN
Nephritic syndrome features
- Hematuria
- Azotemia
- Oliguria
- Mild to moderate proteinuria
- hypertension
- acute onset
- active urine sediment
Active urine sediment signifies
acute glomerular inflammation
What is active urine sediment?
- red cells
- dysmorphic red cells
- red cell casts
- leukocytes
Membranoproliferative glomerulephritis AKA
MPGN
Membranoproliferative glomerulonephritis is common in?
Adolescents or young adults
Membranoproliferative glomerulonephritis nephritic/nephrotic?
- Usually nephritic
- sometimes nephrotic/nephritic
Membranoproliferative glomerulonephritis course of disease
- slowly progressive
- ~50% develop chronic renal failure in 10 years
Membranoproliferative glomerulonephritis treatment considerations
steroids or other immunosuppressant usually aren’t beneficial
MPGN AKA
Membranoproliferative glomerulonephritis
Type 1: Membranoproliferative glomerulonephritis pathogenesis
5 listed
- immune complexes (IgG, C3) deposited in glomerulus
- complement activation
- alterations of GBM
- Influx of inflammatory cells
- Proliferation of glomerular cells (mesangial cells and endothelial cells = endocapillary proliferation)
Type 1 Membranoproliferative glomerulonephritis light microscopy features
- glomeruli are hypercellular
- due to the proliferation of mesangial cells and endothelial cells (endocapillary proliferation) infiltrating leukocytes
- GBM thickened, double-contours or tram-tracks (duplication of basement membrane)
- Obstruction of capillary loops
Membranoproliferative glomerulonephritis Immunofluoresence microscopy
Deposits of IgG and C3 in granular pattern
Type 1 Membranoproliferative glomerulonephritis electron microscopy features
subendothelial electron-dense deposits
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Type 1 MPGN light microscopy
- glomeruli are hypercellular
- Due to the proliferation of mesangial cells and endothelial cells (endocapillary proliferation), infiltrating leukocytes
- Obstruction of capillary loops
- GBM thickened, double-contours or “tram-tracks” (duplication of basement membrane)
Type 1 MPGN immunofluorescence microscopy
Deposits of IgG and C3 in a granular pattern
Type 1 MPGN electron microscopy
subendothelial electron-dense deposits
Type 2 MPGN AKA
Dense deposit disease
Type 2 MPGN prevalence
Very rare
Type 2 MPGN pathology
- circulating autoantibody termed C3 nephritic factor (C3NeF)
- electron dense deposits are intramembranous
Pauci-Immune GN (ANCA Disease) most common in?
- adults but it also occur in children
ANCA disease AKA
Pauci-Immune GN
Pauci-Immune GN clinical features
- Presents with nephritic syndrome
- Can present with acute renal failure (medical emergency as it is potentially life-threatening)
- Treatment: high dose steroids and cyclophosphamide (plasmapheresis is controversial)
ANCA =
Anti-Neutrophil Cytoplasmic Antibodies
What do ANCAs do?
- ANCAs bind to proteins in the cytoplasm of neutrophils
- ANCAs activate neutrophils
- Activated neutrophils incite inflammation in the glomeruli
Pauci-immune GN pathology
- ANCAs bind to proteins in the cytoplasm of neutrophils
- ANCAs activate neutrophils
- Activated neutrophils incite inflammation in the glomeruli
Types of ANCAs
- P-ANCA - perinuclear staining against myeloperoxidase (MPO-ANCA)
- C-ANCA -cytoplasmic staining against proteinase 3 (PR3-ANCA)
P-ANCA =
Perinuclear staining against myeloperoxidase (MPO-ANCA)
C-ANCA =
Cytoplasmic staining against proteinase 3 (PR3-ANCA)
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Pauci-immune GN light microscopy features
- breaks in glomerular capillaries
- cellular crescents
- often neutrophils in glomerular tuft
Pauci-immune GN immunofluorescence microscopy
- no specific staining (or focal weak non-specific staining)
- That’s why it’s called PAUCI-immune GN
Pauci-immune GN electron microscopy
lack of deposits (or scant small deposits present)
Clinical Lab test for ANCA
- nutrophils on glass slide are incubated with patient serum
- ANCA in patient serum bind to neutrophils
- ANCA are detected with fluorescent anti-human Ig
- ***Positive staining is abnormal -> ANCA disease***

Perinuclear vs cytoplasmic staining
