THE RENAL SERIES
Hegde S, Krishnan RG
Children’s Kidney Centre, Department of Paediatric Nephrology
Henoch-Schönlein purpura (HSP) is the most common systemic small vessel vasculitis of childhood. This self limited, multisystem disease is IgA mediated and affects skin, joints, kidneys and gastrointestinal tract but other organs might be affected. Approximately 75% of HSP cases occur in children aged 2-11 years and over 50% under 5yrs.1 Its aetiology is unclear but is associated with various infections (bacterial, viral, parasitic), medications, vaccination and malignancies.
Renal involvement occurs in 20-100% of children with HSP with a wide spectrum of manifestations ranging from microscopic haematuria and mild proteinuria to nephritic/nephrotic syndrome or even rapidly progressive crescentic glomerulonephritis and renal failure.
The pathogenesis of HSP is poorly understood. IgA plays a critical role, as evidenced by increased serum IgA concentrations, IgA-containing circulating immune complexes, and IgA deposition in vessel walls (leucocytoclastic vasculitis) and renal mesangium. IgA nephropathy has developed in patients with a history of HSP. HSP and IgA nephropathy have occurred in the same families.
A. Clinical features
Table 1 HSP affects multiple systems
Joints (50 -80%)
Purpuric rash Urticarial rash Subcutaneous oedema
Nausea & vomiting
Intestinal bleed Intussusceptions Pancreatitis
Proteinuria Hypertension Renal failure
Periarticular oedema (ankles/knees)
Orchitis Testicular torsion
Diagnosis is mainly clinical. The following criteria can be used:
Table 2 Diagnostic criteria for Henoch–Schönlein purpura2
Palpable purpura (mandatory) in the presence of at least one of the following four features:
1. Diffuse abdominal pain
2. Arthritis (acute) or arthralgia
3. Renal involvement (any haematuria and/or proteinuria)
4. Any biopsy showing predominant IgA deposition
It is essential to rule out any other cause of a non-blanching rash, meningococcal sepsis, systemic lupus erythematosus (SLE), Wegeners, microscopic polyarteritis, polyarteritis nodosa and acute haemorrhagic oedema of infancy.
ALL patients – need clinical assessment, weight, blood pressure measurement and urine dipstick.
Selected patients (needing admission, unwell, uncertain diagnosis) – need the following investigations, to assess extent of organ involvement and exclude other causes (Table 3).
FBC, Clotting, U&E, LFT, bone profile, auto antibodies, C3, C4, ANA, dsDNA, ANCA, immunoglobulins Unwell child - Blood cultures, swabs, urine for microscopy and culture, Viral serology & throat swabs Nephritic child - ASOT and antiDNAse B titres
ratio (EMU sample) if proteinuric on dipstick
Renal/Abdominal US where indicated (suggestive features present)
EMU= early morning urine
Admit if the patient is unwell, has significant of joint pain, severe abdominal pain, GI haemorrhage, neurological symptoms, hypertension, evidence of acute glomerulonephritis, nephrotic syndrome or abnormal renal function.
E. Clinical course
HSP is usually self-limiting (most remit within 6 weeks) with mortality of <1%. A proportion of children (up to 25-40%) may relapse. Significant morbidity is associated with disease of the gastrointestinal (GI) tract in the short term and nephritis in the long term.
There is no specific therapy.
Table 4 Outlines of management for involvement of different systems
Renal involvement may precede skin manifestations (1-4% of patients) but is usually evident during the acute phase of the disease (within the first 4 weeks of illness in 85% patients4 and within 3 months in 97–100% of cases, but rarely can present as late as a year). In most cases, the severity of nephritis is not related to the extent of other HSP manifestations but often correlates with findings on biopsy (percentage of glomeruli with crescents may be the most important prognostic indicator).
Rarely, hypertension can be a sole manifestation of renal involvement (with normal urinanalysis)4 and is usually of mild to moderate degree. However, a search for an additional/different cause might be warranted5 if the hypertension is of severe degree, is associated with evidences of target organ damage and/or if it persists after all other manifestations of HSP have resolved.
Long-term renal impairment has been reported in up to 19.5% of those with a history of nephritic or nephrotic syndrome.6 HSP nephritis (HSPN) accounted for up to 15% of children with end-stage renal failure according to previous reports7 but recent data8 put it at 1.8–3%, probably due to the better management of HSP nephritis in recent years.
1. Renal manifestations and its relation to outcome
2. Monitoring for renal involvement - See flow chart (modified based on Ref 1)
3. Referral to paediatric nephrologist - See flow chart1
4. Early referral to Paediatric Nephrologist is indicated for children with –
Children with HSP needing early referral to paediatric nephrology
Acute glomerulonephritis Nephrotic syndrome Persistent hypertension
Persistent (>2+ on dipstick) or increasing proteinuria Macroscopic haematuria lasting >5days/ >1 episode Impaired renal function
The aim is for early detection of those with severe renal involvement, for treatment with immunosuppression, prior to the development of renal scarring.
5. Renal Biopsy-
Kidney biopsy is usually considered if the child has –
1. Nephrotic syndrome
2. Nephrotic range proteinuria (early morning urinary protein: creatinine ratio >250 mg/mmol for >4- 6 weeks)
3. Acute nephritic syndrome
4. Acute renal failure (pre-renal cause excluded)
5. Early morning urinary protein: creatinine ratio >100 mg/mmol for >10-12 weeks
6. Treatment of HSP nephritis
There is no specific therapy but there is a risk of long-term consequences for those with untreated significant renal disease. Treatment of HSPN remains controversial, due to lack of clear evidence of the benefits of treatment. Therapy is often based on data from a number of uncontrolled case series showing some benefit of immunosuppressive therapy. The various therapeutic options can be used alone or in combination, usually based on clinical parameters and biopsy findings.
a. Prevention of HSP nephritis
At the current time insufficient data are available to support early prednisone therapy to prevent renal involvement and hence not recommended.9
b. Treatment of established nephritis9 (following renal biopsy)
The therapeutic options for moderately severe disease (acute nephritic or nephrotic syndrome or persistent non-nephrotic proteinuria with normal renal function and < 50% crescents or sclerosing lesions on biopsy) include steroids, fish oil, cyclophosphamide, angiotensin converting enzyme inhibitors and tonsillectomy. Optimum therapy for rapidly progressive or crescentic HSP nephritis is also less clear and various agents including steroids, cyclophosphamide, ciclosporin, azathioprine, mycophenolate mofetil, angiotensin converting enzyme inhibitors and plasmapheresis are used, either alone or in combinations.
7. Outcome/follow up
Children with renal manifestations in the acute phase require prolonged follow-up, as renal involvement is the most important prognostic factor in determining the long term morbidity and mortality.
In patients, who present with a nephritic, nephrotic, or nephritic/nephrotic syndrome, 19.5–44% have hypertension or impaired renal function on long-term follow-up, whereas 82% who present with haematuria (with or without mild proteinuria) are normal.6, 10 For those with established HSP nephritis persistent proteinuria has been noted be a good indicator of disease progression.11 Overall 1–5% of children with HSP progress to end-stage renal failure.
Those with normal urinalysis6 and no evidence of renal disease are unlikely to be at risk of long term renal damage and can be safely discharged after 6–12 months.
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6. Narchi H. Risk of long term renal impairment and duration of follow-up recommended for Henoch-Schönlein purpura with normal or minimal urinary findings: a systematic review. Arch Dis Child 2005;90:916-20
7. Meadow SR. The prognosis of Henoch-Schönlein nephritis. Clinical Nephrology 1978;9:87-90
8. Lewis MA, Shaw J, Reid C et al. Report of the Paediatric Renal Registry. In
9. Zaffanello M and Fanos V. Treatment-based literature of Henoch-Schönlein purpura nephritis in childhood. Pediatr Nephrol 2009;24:1901-1911
11. Coppo R, Andrulli S, Amore A et al. Predictors of outcome in Henoch-Schönlein nephritis in children and adults. Am J Kidney Dis 2006;47:993-1003
Detection and monitoring of patients with HSP /HSP nephritis