Glomerulonephritis (basic breakdown)

-Can be acute, chronic, or due to RPGN

1. Anti-GBM  disease 
2. Pauci-immune GN
   1. GPA
   2. EGPA
   3. MPA
3. Immune Complex GN
   1. Systemic involvement
      1. SLE
      2. Endocarditis
      3. Cryoglobulinemia
      4. HSP
   1. Isolated Renal
      1. IgA Nephropathy
      2. IRGA (Infection Related GN)
      3. MPGN

Clinical presentation of Glomerulonephritis

–Hematuria
–Dysmorphic RBC or RBC casts
-Sub-nephrotic range usually (but can be nephrotic range) proteinuria often with renal failure
-HTN
-Edema

How do you distinguish the etiology of an immune complex GN? 

                                      Check COMPLEMENT levels!

Diseases with LOW complement

1. SLE (low C3 and C4 and often + ANA Anti-dsDNA)
2. Cryoglobulinemia (Low C4 and C4, often associated with HCV with + Cryo)
3. Endocarditis (Low C3, RF for endocarditis, fever, + BC etc.)
4. IRGA (usually low C3, now always PSGN and Staph related GN is just as common now)-classic teaching is that PSGN occurs weeks after infection but can occur concurrently with infection with other etiologies such as Staph!)

Diseases with NORMAL complement

1. HSP (only systemic IC disease with normal complement)
2. IgA nephropathy (often compared to PSGN which has low complement and usually occurs weeks after infection later than with IgA nephropathy)

Lupus Nephritis

-Making the diagnosis of Lupus is commonly done using the SLICC criteria (see below).

-While not part of the criteria, SPLENOMEGALY can be seen with SLE like our patient and should make you suspect SLE!
-There are SIX classes of Lupus Nephritis and biopsy is important to guide therapy
-Nearly everyone with SLE requires a renal biopsy EXCEPT those with

1. Protein excretion <500 mg/day
2. Bland urine sediment (no dysmorphic RBC, RBC casts)
3. Normal creatinine