Department of Pediatrics.*
|Henoch Schonlein Purpura (HSP) is the commonest form of vasculitis in children. Skin, gastrointestinal tract, joints and kidneys are most frequently affected; occasionally other organs (brain, testes, pancreas) may be involved. About 75% cases occur below 10 years and the incidence is higher in boys. HSP is relatively uncommon in India, but it is likely that mild purpura may go undetected in dark - skinned subjects. The etiology is unknown. The role of a preceding bacterial or viral infection is not established.
Purpura is usually seen on the extensor surface of legs and buttocks. Ankle and knee joints are mostly affected and the pain may be quite severe. Abdominal pain, vomiting and malena occur in about 60-80% cases and may precede the appearance of rash. The severity of these is variable and unusual presentations are common. Renal involvement, indicated by gross or microscopic hematuria and proteinuria, is present in < 75% cases. Frank acute nephritic features with or without nephritic syndrome, indicating severe glomerular injury, are infrequent. In about 60% cases the disease runs its entire course within 4 weeks. Recurrences of rash and abdominal pain are common but milder and of shorter duration.
Several abnormalities concerning IgA have been reported. Serum IgA levels are increased in about 50% cases and IgA antinuclear cytoplasmic antibodies, IgA antiendothelial antibodies, circulating IgA immune complexes have been found. Skin biopsy shows leukocytoclastic vasculitis, with perivascular infiltration of neutrophils and mononuclear cells, involving capillaries and venules of upper and mid-dermis. Immunofluorescence (IF) examination shows deposition of IgA in skin and in glomerular mesangium. Occasionally, deposits of C3 and fibrinogen may be seen. Complement abnormalities have also been reported but a role for complement activation in the pathogenesis of HSP is not proven. Renal biopsy typically shows focal segmental glomerulonephritis. In severe renal involvement extensive crescent formation may be seen. If shows predominant IgA deposits in mesangium.
In the majority of cases supportive treatment (control of joint pain, maintenance of fluid and electrolyte balance) is sufficient. Corticosteroid therapy is used to manage persistent abdominal pain, severe edema, orchitis and cerebral involvement; it should be avoided to treat purpura and joint pain. Milder renal involvement does not require specific therapy. Intravenous pulse methylprednisolone, cyclophosphamide, and in intractable cases plasmapheresis, are judiciously employed to treat the rare severe GN with extensive crescent formation.
Outcome and Prognosis
There is significant morbidity in the acute stage from gastrointestinal complications such as severe bleeding and intussusception and perforation. Renal involvement is the chief long term concern. A variable proportion of cases (1-5%) have been reported to progress to end stage renal disease. Whereas those with severe involvement at the onset (e.g., showing crescentic GN) have a poor outcome, clinical prediction is not possible. Proteinuria and hypertension occasionally reappear after several years of normal renal findings. Prolonged observation is therefore necessary.
Reference: Tizard EJ. Henoch-Schonlein purpura. Arch Dis Child 2999;80:380-83.
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