VASCULITIS AND THE KIDNEY IN CHILDHOOD
Dillon MJ
Great Ormond Street Hospital
for Children, London, UK
The major forms of vasculitis
in childhood are the following: polyarteritis nodosa (PAN), microscopic
polyangiopathy (MPA), Kawasaki disease (KD), Wegener’s granulomatosis (WG),
Henoch-Schönlein purpura (HSP), vasculitis with connective tissue diseases
(CTD) and Takayasu arteritis (TA). In PAN medium sized muscular arteries, including
renal arteries, are affected and renal angiography is diagnostically
helpful even if the kidneys are not overtly affected. MPA usually presents with
crescentic glomerulonephritis (CGN) and patients are often p-ANCA
positive. In KD renal
vasculitis and tubulointerstital nephritis are recognized
complications. WG patients may
not initially have renal involvement but with time this evolves and not
infrequently c-ANCA is present.
In HSP renal manifestations are common but outcome is generally good
although a proportion of patients go on to end stage renal failure. CTD (lupus, dermatomyositis etc)
may have vasculitic components that involve the kidney but these need
distinguishing from the renal disease of the underlying condition. TA affects the kidney by means of
renal arterial narrowing or occlusion associated with aortitis and later
development of hypertension and ischaemic renal failure.
Induction therapy of PAN, MPA
and WG is similar usually involving steroid, cyclophosphamide, antiplatelet
therapy and occasionally plasma exchange. Maintenance treatment consists of steroid and
azathioprine or cyclosporin or mycophenylate mofitil. KD treatment consists of aspirin
and immunoglobulin but with steroid used if unresponsive. HSP management is usually
symptomatic but there is evidence that steroid might modify nephritis and
CGN requires aggressive steroid and immunosuppressives. In TA acute therapy involves
steroid and immunosuppressives but angioplasty and vascular surgery may be
necessary subsequently. New
immunosuppressives and monoclonal antibody therapy are opening up
alternative avenues for treatment in severe vasculitides.
Mortality rates for severe
vasculitides (PAN, WG) are of the order of 8-12% but long term morbidity is
high especially for conditions such as WG and TA.