Nephritis Pathology Flashcards
clinical manifestations of nephritic syndrome
- hematuria
- urine RBC casts
- proteinuria (usually less than 3 g/24 hrs, less than NS)
- sometimes HTN
- varying renal failure, stages: asymptomatic w/ hematuria/proteinuria, acute GN, rapidly progressive GN, chronic GN
6 DDx for nephritic syndrome
- membranoproliferative GN
- IgA nephropathy
- lupus nephritis
- acute post infectious GN
- ANCA GN
- anti GBM GN
why is MPGN unique for nephritis (2)
often presents w/ both NS and GN
can be either immune complex or C3 glomerulopathy
histo LM changes w/ MPGN
thickened walls AND hypercellularity- some in lumen, some in mesangium
4 broad GN mechanisms
all immune dysfn:
- immune complex GN
- C3 glomerulopahty
- anti GBM GN
- ANCA GN
how to distinguish two types of MPGN
IF-
immune complex will have Ig AND C3 deposits in granular pattern
C3 MPGN will have C3 deposits but no Ig
causes for different types of MPGN
immune complex- infection, autoimmunity, neoplasia
C3- complement dysregulation (alternate pathway)
can have overlap! infectious provocation and complement dysfn
describe the general progression of glomerular injury patterns (4), along w/ clinical manifestations
- mesangial hypercellularity- mesangioproliferative GN, asymptomatic to mild nephritis
- endocapillary hypercellularity -focal/diffuse proliferative or necrotizing GN, moderate to severe nephritis (maybe RPGN)
- extracapillary hypercellularity (crescentic)- severe to RPGN
- sclerosis (sclerosing GN)- chronic nephritis
way to separate 4 GN mechanisms by IF
immune complex- granular w/ Ig and C3
C3 GN- granular for C3 and little/no Ig
anti GBM- linear GBM Ig
ANCA- paucity of staining for Ig and complement
2 main causes of immune complex GN, populations
lupus nephritis (AA females) and IgA (whites/asians)
both the predominant causes in younger pts (under 50)
why biopsy w/ SLE and GN?
assess severity and chronicity- often not used for Dx w/ other signs/ Sx of lupus
classes 1-6 of lupus GN
based on patho pattern
1- normal histo
2- mesangioproliferative
3- focal prolferative/ necrotizing (mesangial and subendothelial deposits, endocapillary leukocytes)
4-diffuse proliferative/ necrotizing
5- membranous GN (subepithelial deposits)
6- sclerosing
clinical note of stage 5 lupus nephritis
membranous lupus GN causes nephrotic proteinuria
by far most common GN for asians
IgA
patho pattern for IgA nephropathy
IgA mesangial deposits- hypercellularity and more matrix in mesangium w/ LM
IgA stain on IF
progression of IgA compared to lupus
more on the left end of the spectrum (further from crescentic and sclerosing)- more common w/ mesangioproliferative, proliferative
slower progressing, does not need as aggressive Tx
manifestations of IgA vasculitis (henoch schonlein purpura)
systemic variant of IgA nephropathy- affects skin (purpura, raised and palpable) and GI tract
mechanisms for acute postinfectious GN (PIGN)
immune complex and/or C3 GN
clinical key for acute PIGN
most often follows strep or staph infection- pay attention to past illnesses, rashes, etc
pathological pattern of PIGN (think 3 modalities- LM, EM, IF)
diffuse proliferative GN
PMN infiltration and sub-epithelial humps of deposit visible by EM
granular deposits by IF, IgG and/or C3
2 categories of anti-GBM disease
w/ lung hemorrhage- goodpasture
w/o- anti GBM GN
IF and LM presentation of anti GBM
linear deposition in IF- b/c anti GBM Abs target type IV collagen antigens, deposit in line along GBM
LM often has crescentic to sclerosing pattern
detection of ANCA
IF microscopy assay for PMN cytoplasm autoAb
can specify b/w MPO ANCA and PR3-ANCA
ANCA population
older pts- 50-80
ANCA vasculitis effect on different vessel types
arteries: abdominal pain, skin nodules/ ulcers
capillaries: GN, pulm capillaritis
venules: purpura (leukocytes in dermis)
3 patterns of pulm inflammation from ANCA vasculitis
MPA- hemorrhagic capillaritis
GPA- necrotizing, granulomatous vasculitis w/ giant cells
eGPA- GPA w/ eosinophils
4 possible ANCA diseases
RLV - renal limited, nothing systemic
MPA- vasculitis w/o granulomas or asthma
GPA- vaculitis w/ granulomas, no asthma
eGPA- vasculitis w/ granulomas and asthma
