12.4: Nephritic syndrome Flashcards
What are the two hallmark findings of nephritic syndrome?
Glomerular inflammation and bleeding, leading to oliguria and azotemia
What is the amount of proteinuria in nephritic syndrome? Nephrotic syndrome?
Nephritic = less than 3.5 g /day
Nephrotic = more than 3.5 g /day
Where does edema present with nephritic syndrome, if at all? Why does this occur?
around the eyes d/t salt retention
What are the urinary findings with nephritic syndrome?
RBC casts and dysmorphic RBCs in urine
Why is there HTN with nephritic syndrome?
Salt retention
Why are there casts with nephritic syndrome?
Necrotic RBCs get stuck in the tubules, forming the shape (cast) of the tubule
A bx of the glomerulus with nephritic syndrome will reveal what?
Inflamed, hypercellular glomeruli
What is the underlying pathophysiology of nephritic syndrome?
Immune complex deposition, which activates complement (C5a) and attracts PMNs
What complement is activated by the immune complexes deposited in nephritic syndrome, and mediates the PMN damage?
C5a
What causes the hypercellularity within the glomerulus with nephritic syndrome?
PMNs are attracted to the C5a produced by immune complex deposition
What is post-streptococcal glomerulonephritis?
Nephritic syndrome that arises after group A, beta-hemolytic strep infection of the SKIN or PHARYNX
What is the virulence factor carried by the GAS species that mediate PSGN? What is the function of this protein, and how does this cause PSGN?
- M protein
- Antigen variation/mimicry
True or false: PSGN only occurs with GAS
False- can occur with other, non-strep organisms as well
What are the s/sx of PSGN (4), and when do these occur, relative to the initial strep infection?
- 2-3 weeks after infx
- Hematuria (cola-urine)
- Oliguria
- HTN
- Periorbital edema
In whom is PSGN usually seen in?
Children
What are the findings of PSGN in LM, EM, and IF?
LM = hypercellular, inflamed glomeruli EM = Subepithelial humps IF = granular IF
What causes the subepithelial humps seen with PSGN?
immune complexes build up in the BM, translocate to the epithelium, and aggregate
What is the treatment and prognosis for PSGN?
Supportive and benign, but rarely progresses to renal failure
What is RPGN?
Nephritic syndrome that progresses to renal failure within weeks to months
What are the LM findings of RPGN?
Crescents in bowman’s space
What are the crescents comprised of that fill Bowman’s space with RPGN? (2)
Fibrin and macrophages
What RPGN disease has a linear immunofluorescence? Why is it linear?
Goodpasture syndrome.
Linear because there is a line of antibodies against the BM
What is Goodpasture syndrome? S/sx? Who does this usually occur in?
Antibody against collagen IV, leading to hematuria and hemoptysis
Young male adults affected
What are the two causes of granular appearance of immune complexes on IF, in order of incidence?
- PSGN
2. Diffuse proliferative glomerulonephritis
What causes the granular appearance on IF of PSGN and diffuse proliferative glomerulonephritis?
Subendothelial deposits of antigen complexes
What is the most common renal disease found in SLE?
Diffuse proliferative glomerulonephritis
What is the cause of nephritic and nephrotic syndrome with SLE pts? Which is more commonly seen?
Nephritic = diffuse proliferative glomerulonephritis
Nephrotic = Membranous nephropathy
What is pauci-immune pattern of immune complexes? In which nephritic syndromes (3) is this seen?
Negative IF:
- Wegener’s granulomatosis
- Microscopic polyangiitis
- Churg-Strauss syndrome
What is the next step in the workup of a pt with a pauci-immune IF?
ANCA
What is the basis of the ANCA test? Results (2)
Take a PMN on a slide, and apply ab.
If ab binds to nucleus = pANCA
If ab binds in cytoplasm - cANCA
cANCA is associated with what disease? pANCA?
cANCA = Wegener’s granulomatosis
pANCA = Churg-strauss syndrome
What are the three locations that are involved with Wegener’s granulomatosis?
- Lungs
- Kidneys
- Nasopharynx
Pt with hematuria, nephritic crescent syndrome, and hemoptysis = ? What about if they also have pharynx associated problems?
Goodpasture
Wegener’s with pharynx
What are the three things that will be present in Churg-Strauss syndrome that are not present in microscopic polyangiitis?
- Granulomatous inflammation
- Eosinophilia
- Asthma
What is the most common cause of nephropathy worldwide?
IgA nephropathy
What is the underlying pathophysiology of IgA nephropathy?
IgA immune complex deposition in the mesangium of the glomeruli
When does IgA nephropathy usually present? What are the s/sx?
- Childhood, following mucosal infx
- Episodic gross or microscopic hematuria with RBC casts
What is the prognosis for IgA nephropathy?
May slowly progress to renal failure
Where does IgA deposit in the glomerulus?
In the mesangium
What is Alport syndrome? What is the inheritance pattern? How does it present (3)?
XLR defect in type IV collagen, resulting in thinning and splitting of the glomerular BM
Presents as isolated hematuria, sensory hearing loss, and ocular disturbances
What causes the hearing loss and ocular disturbances with Alport syndrome?
Damage to BM in both cases, caused by crappy type IV collagen
