glomerulonephritis Flashcards
• terms used to describe histologically the number of glomeruli affected in a given condition:
diffuse: majority of glomeruli abnormal (>50%)
focal: some glomeruli affected
terms used to describe histologically the extent to which individual glomeruli are affected in a given condition:
global: entire glomerulus abnormal
segmental: only part of the glomerulus abnormal
proliferation
hyperplasia of one of the glomerular cell types (mesangial, endothelial, parietal epithelial), +/- inflammatory cell infiltration
membranous changes
capillary wall thickening due to immune deposits or alterations in basement membrane
crescent formation
parietal epithelial cell proliferation and mononuclear cell infiltration form crescent-shape in Bowman’s space
gold standard to assess degree of proteinuria
24-h urine protein
microalbuminuria defn
ACR ≥2.8 mg/mmol (female) or ≥2.0 mg/mmol (male)
screen for diabetic nephropathy
urine ACR
normal daily excretion of protein
<30g albumin
microalbuminuria, proteinuria, nephrotic syndrome
30-300mg albumin, 300mg-3g protein, >3.5g protein with hypoalbuminaemia (<35g/L)
ix for nephrotic syndrome or nephritic syndrome
Nephrotic: Urinalysis FBE, UEC, LFT, CRP/ESR Glucose Serology: ANA, RF, p-ANCA, c-ANCA, HBV, HCV, HIV, ASOT Immunoglobulins Urine MCS, 24h urinary protein and creatinine Renal ultrasound
Nephritic is same, but add 24h urine stone workup if there is a history of stone formation
indications for nephrology referral
heavy proteinuria (ACR >30mg/mmol) or nephrotic syndrome
broad categories of proteinuria
tubulointerstitial, glomerular, overflow
tubulointerstitial proteinuria
impaired resorption
s syndrome
glomerular proteinuria categories
primary, secondary
primary glomerular proteinuria
minimal change, membranous, FSGS, membrano-proliferative, post-strep, IgA
secondary glomerular proteinuria categories
systemic disease hereditary/metabolic infectious medications cancer others
secondary glomerular proteinuria systemic disease
diabetes, SLE, vasculitis
hereditary/metabolic
Alford’s, PCKD, Fabry’s, SCD
infectious
HBV, HCV, HIV, bacterial endocarditis
medications
NSAIDs, gold, heavy metals
cancer
lymphoma, RCC
others
cryoglobulinaemia, hypertensive nephrosclerosis
overflow proteinuria
overflow of low molecular weight proteins e.g. multiple myeloma, amyloidosis, Waldenstrom’s macroglobulinaemia
urine workup for gross haematuria
Centrifuge.
If sediment red - true haematuria (RBC+, dipstick+)
If supernatant red (RBC-) - dipstick for haeme
If dipstick+, myoglobinuria or haemoglobinuria
If dipstick-, pseudohaematuria (beetroot, rifampicin, porphyria)
primary nephritic syndrome causes
post-strep IgA rapidly progressive membrano-proliferative interstitial nephritis papillary necrosis
features of nephritic syndrome
PHAROH proteinuria haematuria azotemia RBC casts oliguria hypertension
acute nephritic syndrome defn
a subset of nephritic syndrome in which the clinical course proceeds over days
nephritic syndrome pathology types
- Anti-GBM mediated (15%)
- Immune complex mediated (24%)
- Non-immune mediated (60%)
- Double antibody positive
anti-GBM mediated pathology
anti-GBM positive. linear inflammatory pattern due to IgG and C3 deposition along the capillary loops.
anti-GBM ddx
with lung haemorrhage: goodpasture’s
without lung haemorrhage: anti-GBM
type II pathology
granular pattern due to sub endothelial or subepithelial deposits of IgG and C3
type II ddx
C3 normal - IgA nephropathy, HSP
C3 decreased - post-strep, membrano-proliferative, SLE, IE, cryoglobulinaemia
type III pathology
pauci-immune. no immune staining. ANCA +ve
type III ddx
c-ANCA +: granulomatosis with polyangitis
p-ANCA +: microscopic polyangitis, churg-strauss
type IV pathology
features of type I and type III. double anti-body positive
lab features of RPGN
fibrous crescents on histopathology
RBC casts and/or dysmorphic RBCs in urine
