IgA vasculitis (Henoch-Schönlein purpura): Renal manifestations

IgA vasculitis (Henoch-Schönlein purpura): Renal manifestations

 

IgA vasculitis (Henoch-Schönlein purpura): Renal manifestations

 

Renal affection has been observed in about 20-54 % of children with IgA vasculitis (IgAV) and may be more prevalent among older children & adults. Risk factors that predict renal involvement still uncertain, but many associated clinical & lab features have been observed as possible risk factors. IgAV is characterized by the tissue deposited IgA-impeded immune complexes. Renal histologic findings are similer to those in IgA Np, indicating that both disorders may own a same pathogenesis.  Renal involvement (IgAV nephritis) typically seen within a few days to one mo after onset of systemic Sms. The most common presentation is👉 microscopic or macroscopic glomerular (dysmorphic) hematuria with or without RBCs casts + mild/moderate proteinuria. Nephrotic-range proteinuria, high SCR, and/or HT are present in a minority of ptns; these findings are associated with a worse renal prognosis. IgAV nephritis is usually mild in childhood, while in adults are more liable to exhibit moderate/severe disease. Ptns with IgAV who do not present with renal disease should be observed for the evolution of IgAV nephritis.  

 

Dgx of IgAV nephritis is typically depends upon the clinical picture. If further confirmation is required, a skin biopsy can be performed. A kidney biopsy is generally reserved for ptns in whom the Dgx still uncertain or having more severe renal affection. Generally, kidney biopsy is performed in all ptns with suspected or confirmed IgAV nephritis presenting with proteinuria >1 g/d and/or decline in kidney function to evaluate the severity of the histologic lesions (especially the magnitude of crescent formation) that may impact the protocol of therapy as well as its prognostic implications. Ptns with IgAV with no renal affection at time of presentation, steroid therapy is NOT recommended to guard against the development of IgAV nephritis. Therapy of IgAV nephritis depends primarily upon whether ptn is a child or an adult & upon the intensity of the renal disease:

 

Children with IgAV nephritis, suggested treatment is as follows:

1)    Children seen with limited renal involvement (ie, microscopic/macroscopic hematuria, proteinuria <1 g/d, & normal SCr), No need to ttt with im/m. (immunosuppressive therapy) for IgAV nephritis. No need also to start routine 👉ACEi or ARB, as such ptns typically show full recovery without these medications. We can monitor urinary proteins once/week/one month, then every 2 weeks for 2 months to assess disease progress. Ptns developing rise in proteinuria >1 g/d, > kidney biopsy to assess the need for more aggressive intervention.

2)    Children presenting with more severe renal disease (ie, proteinuria >1 g/d, high SCr, or showing crescentic GN on biopsy) > im/m. therapy with steroids rather than no im/m. or other im/m. agents. We start 3 pulses of IV methylprednisolone 1 g/1.73 m² (one dose/d., or alternate days, for 3 doses), followed by oral prednisone 30 mg/m² (once/d/one mo, then EOD for 2 mo). Monitoring urine protein excretion once/week/one mo, then every 2 weeks/ 2 mo to assess disease progress. With completion of 3 mo of steroids, subseq-uent ttt relies upon the degree of persistent proteinuria & kidney dysfunction.  

 

Adults with IgAV nephritis, our initial approach to treatment is as follows:

1)    Adults presenting with limited evidence of renal affection (ie, microscopic or macroscopic hematuria, proteinuria <1 g/d, & normal SCr), no need to ttt with im/m. therapy for IgAV nephritis. Ptns with proteinuria >0.5 g/d> an ACEi/ ARB to limit proteinuria, unless CI. Monitor urinary proteins & SCr every 2 wks/one mo, then every 2 mo for 6 mo to evaluate disease progress. Ptns developing a rise in proteinuria >1 g/d or a sustained rise in SCr > that expected from use of ACEi/ARB, > kidney biopsy to assess the need for more aggressive ttt.

2)    Adults presenting with more severe renal affection (ie, proteinuria >1 g/d, raised SCr, or crescentic GN on kidney biopsy), > im/m. therapy with steroids rather than no im/m. or other im/m. agents. Then, typical ttt of 6-mo, tapering steroids. Pulse IV methylprednisolone (500 mg-1 g/d/3 ds), followed by oral prednisone (60 mg/d. or 120 mg EOD) can be given. Moreover, all ptns should continue ACEi/ARB to decrease proteinuria, unless CI. Monitor urinary proteins & SCr bi-weekly/one mo & then monthly/ 1^st 6 mo. Subsequent ttt relies upon the degree of persistent proteinuria & kidney dysfunction.

3)    Adults having so many active crescents on biopsy (> 20-25 %), some may start Cph (cyclophosphamide), MMF, or rituximab added to 6-mo of steroids.