Nephritic syndrome Flashcards
What is nephritic syndrome ?
It is caused by damage to glomerular basement membrane causing hematuria and RBC cast in urine.
What is the presentation of nephritic syndrome induced renal failure ?
- Oliguria
- Arterial HTN due to Na+ retention.
- peripheral and periorbital oedema due to increased hydrostatic pressure.
What are the laboratory findings in nephritic syndrome ?
- increased BUN and Creatinine.
- Hematuria
- Proteine urea
- RBC cast in urine.
What is the protein urea threshold in nephritic syndrome ?
< 3.5 g/ day. In severe cases it may exceed > 3.5 gm.
What are the steps to identify the cause of nephritic syndrome ?
- A careful Hx and kidney biopsy.
What are the type III HSRs that can cause nephritic syndrome ?
- PSGN
- IgA nephropathy
- Diffuse proliferative glomerulonephritis
What are the multiple potential ethologies of nephritic syndrome ?
- Membranoproliferative glomerulonephritis
- Rapidly progressive glomerulonephritis.
What is the genetic cause of nephritic syndrome ?
Alport syndrome caused by defect in collagen synthesis.
what is the pathophysiology of PSGN ?
It is typically occurs in children after 3 to 4 weeks of streptococcal infection. Strep M-protein mediated IgG-IgM immune complex deposition within the glomerular basement membrane. This will trigger C3 mediated inflammation leading to the release of cytokines, oxidants and proteases causing podocyte destruction.
What are the lab findings in PSGN?
- positive strep titers.
- reduced serum C3.
What is the PSGN immunohistochemistry appearance ?
Stary sky appearance due to the deposition of IgG, IgM and C3 along the GBM and Mesangium.
What is the electron microscopic finding in PSGN ?
Humps of subepithelial deposits.
What are the light microscopic findings in PSGN ?
Glomerular hypertrophy and hypercellularity.
What is the prognosis of PSGN ?
- It spontaneously resolves in children.
- In adults it can sometimes progress to renal failure.
What is IgA nephropathy or Berger’s disease ?
The immune system incorrectly detects IgA released by the GI pear patches or respiratory IgA
releasing cells during local infections as pathogenic antigen and releases IgG leading to IgA -IgG immune complex deposition in the glomerular mesangium. This causes complement mediated glomerular injury.
What are the microscopic findings in IgA nephropathy ?
Mesangial proliferation.
What is the difference b/w Berger’s disease and Henoch-Schonlein- purpura ( IgA vasculatis) ?
IgA nephritis is localised to the kidney. Whereas in HSP there is coliky abdominal pain, desentery, arthritis and vasculitic nodular palpable skin lesions.
What is DPGN ?
It is an immune complex mediated called lupus nephritis class IV in which > 50% of glomeruli bilaterally affected . The immune complexes consist of Anti-ds-DNA and C3 deposits in the subendothelial space.
What is the light microscopy appearance of DPGN ?
Wire loop appearance due to overall thickening of the capillary wall.
What is membrano-proliferative glomerulo-nephritis ?
There are three types of MPGN they all cause proliferation of glomerular mesangial and endothelial cells.
What is type 01 MPGN ?
It is the most common form of MPGN. It can be idiopathic or secondary to HBV or HCV infection.
What is the pathophysiology of type 01 MPGN ?
It is a type III HSR caused by immune complex deposition formed by the HBV or HCV antigen and immune antibodies. These immune complexes also cause the activation of classical complement pathway leading to complement deposition in the subendothelium. In addition there is also inappropriate activation of alternate pathway by the nephritic factor which converts C3 to C3a and C3b. This process is maintained by the IgG antibodies stabilizing C3 convertes. This will lead to low serum C3.
What is the cause of tram track appearance of GBM in MPGN type 01 ?
It is due to the mesangial cell interpositioning
What is type 02 MPGN also known as dense deposit disease ?
It is caused by nephritic factor, but no immune complex formation involved in it. In type II MPGN the nephritic factor stabilizes C3 convertase enzyme which leads to persistent conversion of C3 to C3a and C3b. However, in contrast to type I MPGN in Type II MPGN the complement deposition happens within the GBM instead of subendothelium.
