Glomerular disease Flashcards
What is the broad definition of nephritic syndrome, conceptually?
Glomerular disorder characterized by inflammation and bleeding due to disruption of glomerular basement membrane.
What findings are associated with nephritic syndrome?
- Limited proteinuria (<3.5g/day)
- Oliguria
- Azotemia
- Salt retention with periorbital edema and HTN
- RBC casts and dysmorphic RBCs in urine
What are the subtypes of nephritic syndrome?
- Acute post-streptococcal glomerulonephritis
- IgA nephropathy (Berger disease)
- Rapidly progressive glomerulonephritis
- Diffuse proliferative glomerulonephritits
- Membranoproliferative glomerulonephritis
- Alport sydrome
What is the classic prelude to PSGN?
~2 weeks after group A streptococcal infection involving pharynx or impetigo. Due to nephritogenic strains that carry M protein.
What is the presentation of PSGN?
Hematuria (cola colored urine), oliguria, hypertension, and periorbital edema.
What kind of hypersensitivity reaction is PSGN?
Type III hypersensitivity, involving immune-complex (antibody+antigen).
What is the appearance of PSGN on light microscopy?
Hypercellular, enlarged glomeruli.
What is the appearance of PSGN on immunoflorescence? Why?
“Starry sky” granular appearance/lumpy-bumpy appearance. Due to immune complex deposition (IgM, IgG, C3) along GBM and mesangium.
What is the appearance of PSGN on electron microscopy?
Subepithelial immune complex humps –> get deposited and pile up.
What is the prognosis of PSGN?
Almost always resolves spontaneously in children– <1% children progress to renal failure.
25% of adults progress to renal failure.
What other lab findings are associated with PSGN?
Incr anti-DNAse B titers (antibodies to strep) and decreased complement levels (used up and deposited)
What is the classic prelude to IgA nephropathy?
2-3 days following mucosal infection (esp gastroenteritis/URI). Common in children, most common nephropathy worldwide.
What is the pathogenesis of IgA nephropathy?
IgA immune complex deposition in MESANGIUM of glomeruli.
What is the presentation of IgA nephropathy?
Episodic hematuria with RBC casts 2-3 days following mucosal infection - often gastroenteritis. May present as acute renal insufficiency.
What are the findings on light microscopy of IgA nephropathy?
Mesangial proliferation
What are the findings on immunoflorescence of IgA nephropathy?
IgA based IC deposits in mesangium
What are the findings on electron microscopy of IgA nephropathy?
Mesangial IC deposits.
What systemic syndrome can IgA nephropathy be involved in?
Henoch-Schonlein purpura.
What organ systems are involved in HSP?
- Skin - purpuric lesions on extensor surfaces
- GI - abdominal pain, vomiting, intestinal bleeding, intuss
- Renal - IgA nephropathy
What will biopsy of HSP purpura show on light microscopy?
Necrotizing vasculitis of small dermal vessels and subepidermal hemorrhage
What will biopsy of HSP purpura show on immunofluorscence?
IgA deposition in dermal capillaries
What is the prognosis of IgA nephropathy?
May slowly progress to renal failure.
What is the presentation of Rapidly progressive glomerulonephritis?
Very rapidly worsening nephritic syndrome that may progress to renal failure in weeks to months
What is the hallmark of RPGN on light microscopy and IF?
Crescents in bowman’s space.
What do the crescents of RPGN consist of?
Fibrin and macrophages, + plasma proteins (C3b), some glomerular cellls
What are three disease processes that may result in RPGN?
- Goodpasture syndrome
- Granulomatosis w/ polyangitis
- Microscopic polyangitis
What are the associated findings with goodpasture syndrome? (sx, hypersensitivity type, IF findings)
Hematuria and hemoptysis.
Type II hypersensitivity, with antibodies to GBM and alveolar basement membrane.
Linear IF.
What are the associated findings with Granulomatosis with polyangitis?
Hematuria/hemoptysis, with granulomatous inflammation.
c-ANCA.
Negative IF.
What are the associated findings with Microscopic polyangitis?
Necrosis on bx.
p-ANCA, MPO-ANCA.
Negative IF.
What is the presentation of Diffuse proliferative glomerulonephritis?
Often presents as nephritic and nephrotic syndromes concurrently