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/ 1st 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.
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