Acute Glomerular Diseases Flashcards
How does the GFR differ for acute glomerulonephritis and RPGN?
Acute- the GFR remains relatively stable
RPGN- the GFR decreases quickly
What are the 2 main types of PRIMARY acute glomerulonephritis?
- idiopathic MPGN
2. IgA nephropathy (10%)
What are the infectious causes of acute glomerulonephritis?
- PSGN (post-strep)
2. bacterial endocarditis
What are the secondary NON-infectious causes of acute glomerulonephritis?
- microangiopathic thrombosis - HUS (hemolytic uremic syndrome), TTP (thrombotic thrombocytopenic purpura)
- SLE, cryoglobinemia, systemic vasculitis
A patient presents with sudden onset edema, hematuria, and loss of renal function 2-3 weeks after a sore throat (or skin rash,,whichever). They have hypertension and acute kidney injury.
What is the cause, usual outcome, and distinguishing features in the lab workup? What will be in the urine?
Cause: Post-strep acute glomerulonephritis
Outcome: most completely resolve after initial episode
Lab for pharyngitis strain:
Increased ASO antibodies and anti-DNAse B antibodies, impetigo, hypocomplementuria
Lab for cellulitis strain:
anti-DNAse B
Urine: RBC casts
A person presents with edema, hypertension, congested circulation. The GFR is measured and is shown to have been declining over a period of weeks to months. (Cr rises by 2mg/dl over 3 months)
Renal biopsy shows cresent formation in the glomeruli
What is the likely diagnosis?
What is the outcome?
RPGN
There is little tendency to spontaneously recover
There are many different IF patterns associated with RPGN.
What are the 2 types that will have linear staining?
- Type 1 Anti-GBM- affects just the kidney. Ab directed against a3 of collagen IV
- Goodpasture’s syndrome- affects the kidney and the lungs
What are the primary causes of RPGN?
What will IF show for them?
- type 1 MPGN
- IgA nephritis
Both have granular staining because they are caused by depositing immune complexes (type 1 MPGN is subendothelial/endocapillary/lobar, IgA is mesangial)
What are the secondary cause of RPGN that have granular staining due to circulating immune complexes?
- SLE
- HUS - with palpable purpura in lower extremities
- post-infectious
What are the 4 causes of RPGN with NO immune deposits?
- idiopathic
- Wegener’s (c-ANCA)
- microscopic polyarteritis nodosa (p-ANCA)
- Churg-Strauss (allergic angiitis- p-ANCA)
What is the effect of RPGN on the excretion of sodium and water? What is the result of this?
In RPGN there is a progressively decreased GFR which means less Na and water are getting excreted. This leads to volume overload, pulmonary congestion and hypoxemia.
Describe the urine osmolarity and the urine [Na] in the early stages of RPGN.
In the early stages, the tubule is still able to reabsorb Na, so the urine Na is low and the urine Osmolarity is high (because the tubules are still able to concentrate urine.
Why does hyperkalemia develop in patients with RPGN?
There is a low filtration rate, so more K is reabsorbed in the proximal tubule.
Na is getting reabsorbed, so there is decreased distal delivery.
Hyperaldosteronism does NOT occur because of the volume expansion from fluid retention
What acid base disturbance is most associated with RPGN?
NG and acid gap metabolic acidosis
What SPECIFICALLY are anti-GBM antibodies being directed at in anti-GBM disease?
a3 chain of type 4 collagen in the basement membrane
A patient presents with subnephrotic proteinuria, hematuria, and sediment with RBC, WBC, and RBC and granular casts.
They also have hemoptysis and anemia. What is the likely cause?
You do a biopsy. What are you likely to find on LM of the kidney?
IF?
Goodpasture’s disease with anti-GBM antibodies directed against the a3 chain of collagen IV in the lungs and kidneys
LM- cresentic glomerulonephritis
IF- linear deposition of IgG on the basement membrane