When we are faced with AKI and classically low c3 and c4, certain diseases come to mind.
A classic figure that has been used for years is below:
I think we can divide the low complement diseases and the kidney with glomerular processes and non glomerular processes
The glomerular diseases that are classically associated with low complements are:
MPGN pattern( all forms, c3GN, DDD, immune complex related MPGN), Lupus related GN, Cyro related GN, infection associated GN( both post strep and endocarditis), but we should not forget Fibrillary GN ( especially if MPGN pattern of injury is noted) and heavy chain deposition disease(HCDD). Finally, we should not forget TMA with complement disorders can cause low c3 in some cases. In other words, immune complex is the main pathology that is driving the hypocomplementemia.
Non glomerular diseases that can be associated with low complements should be kept in mind- classically atheroembolic disease and IgG4 diseases( fair amount have low complements)
Here is a mnemonic that many use- CHAMPS ( created by NephSim)
