23 Proliferative Glomerular Disease Flashcards
Clinical presentation of proliferative glomerular diseases
- Proliferative glomerular diseases usually present as either…
- Major differences
- Proliferative glomerular diseases usually present as either…
- Acute nephritic syndrome
- Rapidly Progressive Glomerulonephritis (RPGN)
- Cannot be applied to any GN in which renal failure develops rapidly
- Crescents must be seen in a high proportion of the glomeruli for the disease to be termed RPGN
- Major differences
- How rapidly the disease develops
- Long-term extent of renal function impairment
Clinical presentation of proliferative glomerular diseases:
Acute nephritic syndrome
- Characterized by…
- Due to…
- Classic presentation
- Characterized by…
- Inflammatory damage of the glomerular capillaries
- –> hematuria/proteinuria, HTN, and azotemia
- Due to…
-
Secondary GN related to infectious disease
- Ex. post-streptococcal GN or other bacterial/viral illnesses
- Other systemic disease
- Ex. lupus, vasculitis, Henoch Schonlein purpura, Goodpasture’s syndrome
-
Primary glomerular disease
- Ex. IgA nephropathy
-
Secondary GN related to infectious disease
- Classic presentation
- Ppost-streptococcal
- Other post-infectious forms of GN
Clinical presentation of proliferative glomerular diseases:
Rapidly progressive glomerulonephritis (RPGN)
- RPGN
- Characterized by…
- Necessary feature to diagnosis RPGN
- Etiologies
- Type I
- Type II
- Type III
- Critical to avoid ESRD
- Renal pathology
- RPGN
- Subtype of the acute nephritic syndrome
- Characterized by…
- Fulminant progressive downhill course
- Associated oliguria or anuria
- Decline in GFR occurs over days to weeks
- If untreated, RPGN –> ESRD
- Causes: primary & secondary
- Necessary feature to diagnosis RPGN
- Many crescents are seen on renal biopsy
- Etiologies
- Type I: Anti-GBM disease/Goodpasture’s syndrome
- Type II: Immune complex mediated
- E.g. membranoproliferative GN, lupus nephritis, cryoglobulin associated GN, Ig A nephropathy, etc.
- Type III: Pauci immune ANCA associated vasculitis
- E.g. Wegner’s Granulomatosis, microscopic polyangiitis, pauci immune crescentic GN
- Critical to avoid ESRD
- Rapid diagnosis with a renal biopsy and institution of therapy
- Renal pathology
- Variable
- Common feature: necrotizing lesions or crescents in a variable % of glomeruli
Glomerular diseases associated w/ cellular proliferation
- Glomerular cellular proliferation is related to…
- Degree of cell proliferation depends on…
- The degree of complement activation
- Chemotaxis
- Serum complement
- Hypocomplementemia
- Diseases associated with hypocomplementemia
- Glomerular proliferation tends to be associated w/…
- Glomerular cellular proliferation is related to…
- Deposition of immune complexes or antibodies in the mesangial subendothelial system &/or the glomerular BM
- Degree of cell proliferation depends on…
- Rate of accumulation of complexes
- The degree of complement activation
- Chemotaxis
- Some complexes readily activate complement –> chemotaxis of inflammatory cells
- E.g. post-infectious GN
- Other deposits don’t cause the same degree of chemotaxis
- Ex. IgA nephropathy
- Some complexes readily activate complement –> chemotaxis of inflammatory cells
- Complement activation may be reflected in serum complement levels
- If severe enough –> hypocomplementemia
- Pts w/ hypocomplementemia almost always have a proliferative glomerulonephritis
- But not all proliferative GN is hypocomplementemic
- Some deposits (ex. IgA) –> significant mesangial proliferation w/o lowering serum complement
- Chemotaxis
- Diseases associated with hypocomplementemia (COMPS)
- Cryoglobulinemia
- AtherOemboli
- Membranoproliferative Glomerulonephritis
- Post infectious glomerulonephritis
- Systemic Lupus erythematosus
- Glomerular proliferation tends to be associated w/…
- A nephritic syndrome including hematuria & RBC casts
Specific proliferative glomerular diseases:
Acute post-infectious glomerulonephritis
- Path description
- Incidence
- Post streptococcal GN
- Incidence
- Cause
- Among…
- Typical features
- Path description
- Diffuse endocapillary proliferative and exudative GN
- Incidence
- 9.5 – 28.5 per 100,000
- Usually occurs in healthy children (can also occur in adults)
- Post streptococcal GN
- Incidence
- Most common cause of post-infectious GN
- Occurs after a streptococcal sore throat or impetigo
- Secondary form of GN
- Caused by Group A, beta-hemolytic Streptococci
- Particularly those of “nephritogenic” strains - Types 1, 4, & 12 (throat) and types 49 & 2 (skin)
- Among the prototypic immune complex diseases
- Streptococcal antigen is only rarely identified
- Typical features
- Acute onset of gross hematuria (cola colored) or microscopic hematuria after latent period of 10-14 d
- Salt and water retention –> edema & HTN
- Urinary sediment is nephritic (w/ blood & RBC casts)
- Proteinuria present but
- GFR is usually depressed
- Elevated serum creatinine
- Occurs suddenly (within days)
- Decreased serum complements
- Increased antistreptolysin O (ASO) titers w/ a preceding throat infection
- Elevated Antihyaluronidase titers (AHT) and anti-DNAse B titers are common with preceding skin infection
- Incidence
Specific proliferative glomerular diseases:
Acute post-infectious glomerulonephritis
- Other causes of acute post infectious GN
- Pathogenesis
- Pathology
- LM
- IF
- EM
- Treatment
- Other causes of acute post infectious GN
- Staphylococcal infection of heart valves (endocarditis) or ventricular shunts
- Visceral abscesses
- All associated w/ protracted infection w/ continuous release of antigen into the circulation.
- Pathogenesis
- Due to an immune response to infection w/ nephritogenic Group A beta-hemolytic streptococcus
- Deposited antibodies may be directed at streptococcal antigens and/or intrinsic glomerular epitopes (ex. ECM)
- Inflammation is caused by local activation of the complement cascade, IL-6, ICAM-1, and the plasmin-plasminogen system
- Pathology
- LM
- Glomerular tufts are enlarged & hypercellular w/ leukocytes in glomerular capillaries
- Diffuse proliferative and exudative GN
- Edothelial/mesangial cell proliferation
- Intracapillary luminal neutrophils
- IF
- IgG and C3 with “lumpy, bumpy” pattern (sparse, coarsely granular)
- EM
- Subepithelial “hump” deposits, “Flame like deposits” and some mesangial deposits
- LM
- Treatment
- Supportive: Na restriction & BP control
- Dialysis if necessary (uncommon)
- Most patients recover normal renal function and don’t have progressive renal failure
- Renal biopsy is generally not required as the diagnosis can be made on the basis of the clinical presentation & serologic tests
Specific proliferative glomerular diseases:
IgA predominant immune complex glomerulonephritis (IgA nephropathy, Berger’s disease)
- IgA nephropathy
- Clinical findings
- Incidence
- Prevalence
- Pathology
- LM
- IF
- EM
- Treatment
- IgA nephropathy
- Most common type of GN in countries w/ routine renal biopsies
- Associated with chronic severe liver disease, psoriasis, inflammatory bowel disease (IBD), and HIV disease
- Clinical findings
- Hematuria (micro- or macroscopic) often precipitated by flu-like illnesses or vigorous exercise
- May or may not be associated with flank pain
- Urinary protein excretion < 2 g/day
- Some pts have nephrotic range proteinuria (poor prognosis)
- Some pts have fulminant course w/ rapid deterioration of renal function.
- Hematuria (micro- or macroscopic) often precipitated by flu-like illnesses or vigorous exercise
- Incidence
- 15 – 40 per million per year
- Prevalence
- 2 – 10% of renal biopsies –> 38% in Native Americans from New Mexico
- Highest in Asia where prevalence is 20-40% of all renal biopsies
- Pathology
- LM: > 1 of…
- Normal
- Diffuse mesangial cell/matrix proliferation
- Focal segmental mesangial and endocapillary cell proliferation
- Necrosis/crescents
- IF
- Predominantly IgA, C3
- IgG and IgM can be present
- EM
- Mesangial electron dense deposits
- Rare subendothelial electron dense deposits in necrotizing forms
- LM: > 1 of…
- Treatment
- No known treatment
- Fish oil for pts w/ progressive renal failure
- Immunosuppressive therapy: not beneficial
- Steroids: possible treatment
- 20 yr renal survival approximately 50% to 70%
Specific proliferative glomerular diseases:
Henoch-Schönlein Purpura (HSP)
- Mediated by…
- Form of…
- Involves…
- Occurs…
- Incidence
- Cause
- Prognosis
- Biopsy
- Renal involvement
- Morphology
- Mediated by…
- IgA
- Form of…
- hypersensitivity angiitis
- Involves…
- Skin (purpuric rash over buttocks, lower extremities)
- Joints (arthralgias)
- GI tract (GI bleeding common)
- Kidneys
- Occurs…
- At any age
- Most common: children 3-10yo
- Incidence
- Rare: 20 / 100,000 children / year
- Cause
- Antecedent infection is common (often streptococcal URI)
- Prognosis
- Most children recover in 4-6 weeks with no lasting kidney damage
- Adults recover more slowly and less completely
- Pts w/ nephrotic syndrome or crescentic GN renal failure may supervene within the first 6 months
- Biopsy
- Necrotizing, leukocytoclastic vasculitis
- Fibrinoid necrosis of vascular walls which contain fragments of neutrophilic debris
- Renal involvement
- Present in ~50% of pts
- Varies from mild hematuria to nephrotic syndrome to fulminant renal failure
- Morphology
- Similar to IgA nephropathy
Specific proliferative glomerular diseases:
Membranoproliferative (mesangiocapillary) glomerulonephritis (MPGN)
- Incidence
- Presentation
- Therapy
- Forms
- Primary (idiopathic)
- Secondary (associated with other diseases)
- Pathology
- Characterized by…
- LM
- Incidence
- Rare group of disorders (2-3 / 1,000,000 / year)
- Presentation
- Proteinuria (often nephrotic range)
- Hematuria
- HTN
- Nephrotic or nephritic syndrome
- Low C3 (< 70% of cases)
- Often progresses to renal failure
- Therapy
- No accepted therapy
- Forms
-
Primary (idiopathic)
- Type I: mesangiocapillary glomerulonephritis
- Type II: Dense Deposit Disease
- Type III: Mixed features of Type I and membranous GN
-
Secondary (associated with other diseases)
- With immune complexes
- Autoimmune diseases like SLE
- Infections like hepatitis C, endocarditis, infected ventricular shunt, etc.
- Dysproteinemia like cryoglobulinemia associated with CLL, lymphoma
- Without Immune deposits
- HUS/TTP, transplant glomerulopathy
- With immune complexes
-
Primary (idiopathic)
- Pathology
- Characterized by…
- 1 of 3 alterations in the GBM
- Proliferation of glomerular cells (mainly mesangial cells)
- LM
- Global hypercellularity
- Accentuation of the glomerular segments or lobules (–> lobular GN)
- Characterized by…
Specific proliferative glomerular diseases:
Membranoproliferative (mesangiocapillary) glomerulonephritis (MPGN):
Type I
- Predominantly…
- Silver stain
- Presence of immune complex deposits
- IF
- EM
- Complement levels
- Immune complexes
- Predominantly…
- Mesangial (and variable endocapillary) cell proliferation
- Circumferential extension of the mesangium into the subendothelial space of the capillary wall (mesangial interposition or mesangialization)
- –> thickening of the peripheral capillary wall
-
Silver stain
- Double contour in the capillary walls (tram tracking)
- Corresponds to reduplicated subendothelial lamina densa
- Presence of immune complex deposits
- Occurs in most cases of Type I MPGN including the primary form
- IF
- Mesangial & capillary loop granular positivity for IgG and C3
- Not infrequently C4 and C1q suggesting complement activation by the classical pathway
- EM
- Mesangial interposition
- Reduplication of the lamina rara interna and mesangial
- Subendothelial electron dense deposits
- Complement levels
- Variably decreased
- Immune complexes
- Formed & deposited predominantly in the subendothelial space of the capillary wall
- Stimulates mesangial ingrowth & new BM formation to isolate & remove the deposits
Specific proliferative glomerular diseases:
Membranoproliferative (mesangiocapillary) glomerulonephritis (MPGN):
Cryoglobulinemia
- Specific form of…
- Generic descriptive term given to…
- 3 types recognized by immunoelectrophoresis
- Type 1
- Type 2
- Type 3
- Frequently occur in association w/…
- Clinical syndrome: >1 of…
- Renal disease
- Acute phase
- Chronic phase
- Specific form of…
- Type I MPGN
- Generic descriptive term given to…
- Igs that precipitate on cooling and resolubulize on warming
- 3 types recognized by immunoelectrophoresis
- Type 1 - monoclonal Ig (usually IgM)
- Type 2 - monoclonal Ig (usually IgM) directed against Fc portion of a polyclonal (usually IgG)
- Type 3 - polyclonal Ig (usually IgM) directed against Fc portion of a polyclonal Ig (usually IgG).
- Frequently occur in association w/…
- Other diseases such as plasma cell dyscrasias and hepatitis C
- Clinical syndrome: _>_1 of…
- Purpura, weakness, neuropathy, arthralgias, & frequently glomerular disease (20-55%)
- Renal disease
- Acute phase
- Proliferative & variably necrotizing GN associated w/ neutrophilic exudation and cryoglobulin “thrombi” (subendothelial and mesangial electron dense deposits)
- Chronic phase
- Cryoglobulin deposition produces a type I membranoproliferative pattern of injury
- Acute phase
Specific proliferative glomerular diseases:
Membranoproliferative (mesangiocapillary) glomerulonephritis (MPGN):
Type II & III
- Type II
- General
- IF
- Etiologic agent
- Type III
- Type II
- General
- Similar to types I and III by its H&E LM appearance only
- Lamina dense is transformed into a diffusely thickened & electron dense structure –> “dense deposit disease”.
- IF
- C3 and properdin are deposited on either side of the abnormal lamina densa, but not within it
- Etiologic agent
- Serum autoantibody: C3 nephritic factor (C3NeF)
- Present in 70% of patients
- Stabilizes the alternative pathway C3 convertase (C3bBb), preventing its normal degradation by factors H and I
- –> constitutive alternative pathway complement activation.
- Serum C3 levels are often depressed w/ a normal C4 level
- Dense deposit disease has a predilection to recur in renal transplants
- Dense deposit disease is associated with partial lipodystrophy
- Serum autoantibody: C3 nephritic factor (C3NeF)
- General
- Type III
- Similar to Type I, except subepithelial deposits are also seen
Specific proliferative glomerular diseases:
Systemic lupus erythematosus (SLE)
- General
- Incidence
- Mostly involves the following organ systems
- Lab findings
- Renal involvement
- Incidence
- Presentation
- Immune complex deposition
- Clinical signs
- General
- Multisystem, autoimmune disease w/ antibodies directed against cellular constituents
- Most important: antibodies to native double stranded DNA (anti-ds DNA)
- Incidence
- Predominantly young women (women : men :: 6 : 1)
- Mostly involves the following organ systems
- Skin, joints, serous membranes, heart, neurologic, blood (cytopenias, coagulation disorders), & kidneys
- Lab findings
- Antinuclear antibodies (ANA)
- Depression of C3, C4, CH50
- Circulating immune complexes.
- Renal involvement
- ~4.4 / 100,000
- Can present w/ both nephrotic (heavy proteinuria) & nephritic (hematuria, hypertension, azotemia) syndrome
- Some present w/ tubulointerstitial nephritis
- Immune complex deposition can be detected in 90-95%
- 1/3 not sufficiently extensive to give rise to symptoms
- Clinical signs (hematuria, proteinuria, azotemia) occur when the level of deposits reach threshold
Specific proliferative glomerular diseases:
Systemic lupus erythematosus (SLE)
- 2 principal patterns of immune complex deposition
- Other pathology features
- LM
- IF
- EM
- Treatment
- Depends upon…
- Class IV
- 2 principal patterns of immune complex deposition
-
Mesangial-subendothelial
- Preformed immune complexes deposit in mesangium first
- Later may extend into the subendothelial space
-
Membranous-smaller complexes
- Formed in situ within the BM or subepithelial space
- –> typical subepithelial deposits
-
Mesangial-subendothelial
- Other pathology features
- LM
- Interstitial nephritis; hyaline thrombi; vasculitis-rare; fibrinoid necrosis; wire loop lesions (confluent subendothelial IC deposits); hematoxylin bodies (LE Cells)
- IF
- TBM staining (“full house”)
- Stains with all Igs including IgM, IgG, Ig A and complements
- EM
- “Fingerprint”; tubuloreticular inclusions (endothelial cells); rings and cylinders; TBM deposits
- LM
- Treatment
- Depends upon the class of disease
- The patient can transform from one class to other over the course of the disease
- Pt can initially present w/ class III & can transform to Class V w/o going through class IV
- Why pts usually require multiple renal biopsies during the course of the disease to determine the histological class
- The patient can transform from one class to other over the course of the disease
- Class IV (most aggressive form)
- Steroid & cyclophosphamide
- Resistant cases: other immunosuppressants like Mycophenolate mofetil, cyclosporine and rituximab
- Depends upon the class of disease
Specific proliferative glomerular diseases:
WHO classification of lupus nephritis (LM, IF, & EM for each)
- Class I
- Mesangial (Class II)
- Focal Proliferative (Class III)
- Diffuse Proliferative (Class IV)
- Membranous (Class V)
- Sclerosing GN (Class VI)
- Class I - rare
- LM: Normal
- IF: Negative Staining
- EM: No Deposits
- Mesangial (Class II) 25%
- LM: Loops normal; mesangium increase cells and matrix
- IF: Mesangial
- EM: Mesangial
- Focal Proliferative (Class III) 20%
- LM
- < 50% of glomeruli affected
- Segmental increase cells; adhesions; small crescents
- IF: Mesangial & loop> than changes by light
- EM: Mesangial and segmental small subendothelial
- LM
- Diffuse Proliferative (Class IV) 35-40%
- LM
- > 50% of glomeruli affected
- Marked hypercellularity and matrix increase; crescents; necrotizing lesions
- IF: Mesangial and loop
- EM: Mesangial and large subendothelial
- LM
- Membranous (Class V) 15%
- LM: Thick loops; minimal hypercellularity
- IF: Loop
- EM: Subepithelial; occasional mesangial
- Sclerosing GN (Class VI)
- LM: Advanced sclerosing lesions
- IF: ±Immune deposits
- EM: ±electron dense mesangial, subendothelial and subepithelial