- Joined
- Apr 12, 2018
- Messages
- 7
- Reaction score
- 6
Hey guys, I am about to take my step 1 and thought I'd be nice to share with you a scheme I saw somewhere (Pathoma, I believe) and modified myself. It is almost all you need to know for Nephrotic/Nephritic Sd.
This drawing summarizes the electron microscopy plus immunofluorescence. All of these are "granular" immune complex (IC) deposits. "x" denotes the location of the deposit, being subendothelial, intramembranous, and subepithelial from bottom to top (same direction of glomerular filtration), respectively. If you remember this, the pathophysiology comes very easily.
1. For Membranoproliferative glomerulonephritis (MPGN) 1, since you have subendothelial deposits, mesangial cells will proliferate trying to remove the IC creating mechanical traction in the basement membrane and splitting it, generating the appearance of a "tram-track". This also explains why you find "tram-track" more commonly in MPGN 1 than MPGN 2.
2. Membranous: Podocytes try to repair the damage caused by passing IC through the basement membrane, generating the diffuse thickening seen in light microscopy. This uncontrolled repair causes newly synthesized basement membrane (spikes) to appear in between the interspersed subepithelial deposits (domes). You can remember of this with help of the triangles drawn.
3. PSGN: remember that the IC are due to S. pyogenes infection. Being an exogenous component, the autoimmunity is self-limited. What we see in the electron microscopy are just the IC passing through the glomeruli on their way to excretion. Also explains why treatment is just supportive.
Feel free to criticize and help improve this discussion!
This drawing summarizes the electron microscopy plus immunofluorescence. All of these are "granular" immune complex (IC) deposits. "x" denotes the location of the deposit, being subendothelial, intramembranous, and subepithelial from bottom to top (same direction of glomerular filtration), respectively. If you remember this, the pathophysiology comes very easily.
1. For Membranoproliferative glomerulonephritis (MPGN) 1, since you have subendothelial deposits, mesangial cells will proliferate trying to remove the IC creating mechanical traction in the basement membrane and splitting it, generating the appearance of a "tram-track". This also explains why you find "tram-track" more commonly in MPGN 1 than MPGN 2.
2. Membranous: Podocytes try to repair the damage caused by passing IC through the basement membrane, generating the diffuse thickening seen in light microscopy. This uncontrolled repair causes newly synthesized basement membrane (spikes) to appear in between the interspersed subepithelial deposits (domes). You can remember of this with help of the triangles drawn.
3. PSGN: remember that the IC are due to S. pyogenes infection. Being an exogenous component, the autoimmunity is self-limited. What we see in the electron microscopy are just the IC passing through the glomeruli on their way to excretion. Also explains why treatment is just supportive.
Feel free to criticize and help improve this discussion!
