It is lupus nephritis week! @GlomCon #Lupusnephritis #MedEd #Nephpearls #NephTwitter
To start off: Lupus can affect the kidney in many ways! Read on to find out more!
To start off: Lupus can affect the kidney in many ways! Read on to find out more!
Lupus can affect multiple compartments of the kidney:
🎃Glomerulonephritis (i.e. lupus nephritis, LN)
🎃Tubulointerstitial nephritis
🎃Podocytopathy
🎃Vasculopathy/angiopathy
🎃Glomerulonephritis (i.e. lupus nephritis, LN)
🎃Tubulointerstitial nephritis
🎃Podocytopathy
🎃Vasculopathy/angiopathy
Histopathology🔬 - let’s focus on LN:
The mesangium is a continuation of the subendothelial space. In LN, the deposits initially start in the mesangium and progress to other locations (e.g. subendothelial deposits).
The mesangium is a continuation of the subendothelial space. In LN, the deposits initially start in the mesangium and progress to other locations (e.g. subendothelial deposits).
Classes of LN🎃🧟♂️:
Class 1: minimal mesangial
Class 2: mesangial proliferative
Classes 3 and 4: proliferative w/ subENDOthelial deposits (III: focal<50% Gloms vs IV: diffuse>50% Gloms involved)
Class 5: membranous (subEPIthelial deposits)
Class 1: minimal mesangial
Class 2: mesangial proliferative
Classes 3 and 4: proliferative w/ subENDOthelial deposits (III: focal<50% Gloms vs IV: diffuse>50% Gloms involved)
Class 5: membranous (subEPIthelial deposits)
Misconceptions in LN🛑:
-Subendo proliferation ❌ vs Hypercellularity ✔️: not native cells proliferating but infiltrating inflammatory cells
-C3 C4 are always ⬇️: Sensitivity/specificity=50%/75%(Esdaile 1996 & Valentijn 1985)
Class III+IV ❌ co-exist as they are a spectrum.
-Subendo proliferation ❌ vs Hypercellularity ✔️: not native cells proliferating but infiltrating inflammatory cells
-C3 C4 are always ⬇️: Sensitivity/specificity=50%/75%(Esdaile 1996 & Valentijn 1985)
Class III+IV ❌ co-exist as they are a spectrum.
Suspect LN:
Multiple site deposits (mesangial, subendo and/or subepi)
On IF: Full house pattern (IgA, IgG, IgM, C3, C1q)
Extraglom Immune Complex deposits (eg: blood vessels, TBM)
Tubuloreticular inclusions: subcellular structures in the endoplasmic reticulum>excess IFN (👀 below
Multiple site deposits (mesangial, subendo and/or subepi)
On IF: Full house pattern (IgA, IgG, IgM, C3, C1q)
Extraglom Immune Complex deposits (eg: blood vessels, TBM)
Tubuloreticular inclusions: subcellular structures in the endoplasmic reticulum>excess IFN (👀 below
Case 1: 45 yo F with PMH of SLE and occasional arthritic flares. Presented with subnephrotic range proteinuria (UPCR 1g/g) and low complements. (Images show below)
What does the green and yellow circles show? (Image above)
Correct answer: A 👻 Subendothelial hypercellularity (red circle) due to obliteration of capillary lumens and (green circle) mesangial expansion (>4 nuclei per mesangial area).
On IF staining: IgG notable for granular mesangial and subendothelial deposits. A “wire loop” pattern is noted (red circle) as a result of dense subendothelial deposits.
Further biopsy findings are shown below (light microscopy and electron microscopy).
What is the class of LN shown above?
Answer: Class 3 or 4 due to subendo hypercellularity below w/ crescent formation (green circle) and mesangial+ intramembranous deposits (yellow circle) with no subepi deposits noted on EM. 💡 you need to assess the extent of glom involvement for class III (<50%) or IV (>50%)
Post-tweetorial quiz 🎃: Which of the following is TRUE about LN?
The answer is B! Some pearls about LN:
👻Affect multiple compartments of the kidney
🧟♂️Clinical+path diagnosis
🎃Start as mesangial deposits that can progress to subendo or subepi deposits
🧟EM 🔬 can aid in locating the deposits and extent of glomerular involvement to classify LN
👻Affect multiple compartments of the kidney
🧟♂️Clinical+path diagnosis
🎃Start as mesangial deposits that can progress to subendo or subepi deposits
🧟EM 🔬 can aid in locating the deposits and extent of glomerular involvement to classify LN
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