HSP

Question 1

What

Answer 1

IgA mediated small vessel vasculitis of childhood
Some overlap with IgA nephropathy (Berger’s disease)
Seen in children following an infection
Aetiology

Question 2

Epidemiology/risk factors/triggers

Answer 2

90% occur in childhood, most common vasculitis in childhood
Peak age: 4-6 years. Rare in younger children and infants
M:F 1.5/2:1
Infections: Group A strep, mycoplasma, EBV
Vaccinations
Environmental exposures: eg drug/food allergens, pesticides, cold exposure, insect bites

Question 3

Features

Answer 3

Preceding URTI
Mildly ill, low-grade fever
Symmetrical, erythematous, macular rash becoming palpable, purpuric rash within 24 hours (with localised oedema) - buttocks and extensor surfaces of arms and legs
Polyarthritis
Renal involvement (approx 40%): Features of IgA nephropathy may occur eg haematuria, renal failure, nephritis. Withing 3 months of disease onset Small minority progress to ESKD.
Abdominal pain (and bloody diarrhoea)
GI bleeding
Orchitis

Question 4

Investigations

Answer 4

Urinalysis: haematuria, proteinuria
FBC: Raised SCC, eosinophilia, raised or normal platelets
ESR: raised
U+E: raised creatinine in renal involvement
Serum IgA: raised
Autoantibody screen: connective tissue diseases
If GI symptoms: Abdo US - obstruction; barium enema - intussuception
Orchitis: Testicular US - possible torsion (can mimic symptoms)
Renal biopsy: if persistent nephrotic syndrome

Question 5

Management

Answer 5

Self limiting disease
Supportive - no therapy has been shown to shorten duration or prevent complications
May need admission for monitoring of abdo and renal complications
NSAIDs for joint pain - caution in renal impairment
Renal involvement: supportive (plasma exchange maybe in adults with rapidly progressing nephritis)
Corticosteroids: ameliorate arthralgia and GI symptoms. Does not help prevent long term kidney damage.
People are looking at immunosuppressants but no trials

Question 6

Complications

Answer 6

Renal involvement = 50%; serious = 10%; ESKD = <1%. Renal prognosis worse in older children and adults. Monitor BP, urinalysis and renal function lots in first 6 months and a 12 months
Rare: MI, pulmonary haemorrhage, pleural effusion, intussusception (2-3%), GI bleeding, bowel infarction, seizures and mononeuropathies.
Recurrence of symptoms

Question 7

Prognosis

Answer 7

Usually excellent, especially in children with no renal involvement
Initial episode can last for several months
1/3 will relapse
Younger children (<3): shorter, milder, fewer recurrences
Long term prognosis directly dependent on severity of renal involvement