1) A – ds-DNA in lupus is associated with disease activity (increased in active ongoing lupus nephritis)
2) C – HSP is associated with IgA deposition in mesangium. Note the fleeting type of symptoms, which is classic for HSP a) Intermittent abdominal pain
b) Migratory polyarthritis
c) Waxing and Waning palpable purpuric rash
IgA nephropathy is a primary renal disease secondary to under galactosylated IgA and subsequent IgG orIgA1 antibody against the abnormal IgA with deposition of antigen + antibody complex in the mesangium. HSP is a systemic vasculitis !
3) B – MPO ANCA vasculitis with GPA presentation! Given the RPGN picture, cytoxan and glucocoticoids is the right answer. However, if this question is framed as a very mild case of MPO ANCA associated GPA, rituximab with glucocorticoids is the answer.(RITUXVAS)
4) C – APSGN. Low C3 and normal C4 indicated alternate complement pathway activation(strep infection classically leads to alternate complement activation). You dont expect C1q, C4 in the biopsy !
5) A – Anti-GBM disease
6) D -C3 glomerulopathy. Uninhibited alternate complement pathway activation by the deficiency of complement regulatory factors! In this case factor H related proteins!