Henoch Schonlein Purpura

Question 1

Define Henoch Schonlein purpura

Answer 1

IgA-mediated immune vasculitis involving the small vessels of the joints, kidneys, GI tract, skin, lungs, and the CNS
Most common vasculitis of childhood

Purpura or petechiae with lower limb predominance and at least one of the following:
* Abdominal pain
* Histopathology
* Arthritis or arthralgia
* Renal involvement

Question 2

What is the aetiology of Henoch Schonlein purpura

Answer 2

Unknown cause - believed to derive from abnormal glycosylation status of the IgA protein

Infective trigger, often URTI:
GAS
Hep A/B
CMV
Adenovirus
Mycoplasma
Scarlet fever

Or triggered by vaccination or medication use

Question 3

What are the risk factors for henoch-schonlein purpura

Answer 3

Male
2-10yo
Hx of prior URTI
Hx of allergy and atopy

Question 4

What are the symptoms of henoch schonlein purpura

Answer 4

Purpuric rash (small red/purple dots on the lower limbs and buttocks)

Arthralgia (typically knees and ankles, pain without swelling)
Arthritis (knees and ankles, swelling and pain, restricted ROM)

Abdominal pain (up to 14 days prior, colicky)
Vomiting

Haematuria, ‘cola coloured’ urine, frothy urine
Scrotal swelling (orchitis)

Question 5

What are the differentials for henoch schonlein purpura

Answer 5

Haematological malignancy
Thombocytopenia
Septicaemia

Question 6

What are the signs of henoch schonlein purpura on examination

Answer 6

Obs: HTN (renal impairment)

Purpuric rash
Typically legs and buttocks (spares the trunk)
Palpable purpura/petechiae/ecchymoses
Florid and erythematous
Non-blanching
2-10mm in diameter
Occur in crops, symmetrical over the extensor surfaces

Arthritis: lower limb, swelling and pain and reduced ROM
Oedema

Question 7

What investigations should be done for henoch schonlein purpura

Answer 7

Blood pressure (renal involvement)
Urine dip: haematuria ++, proteinuria

If urine is normal → discharge with advice
Urine abnormal → further investigations

Urine albumin:creatinine ratio: >3mmol/mg, red clasts

FBC: normal (exclude ITP)
U&Es: renal involvement)
Coagulation screen (exclude ITP, sepsis)
LFTs: low albumin
ESR: raised
Serum IgA: elevated
Anti-streptolysin-O-titre: recent strep infection
Autoimmune profile (for significant renal impairment)

Renal US (for significant renal impairment)
Abdo US (exclude intussusception, perforation, orchitis)

Question 8

What is the management for henoch schonlein purpura without significant renal impairment

Answer 8

1. Educate on diagnosis
2. Management of symptoms
   Skin rash: Bed rest, elevate the affected area
   Joint pain: ibuprofen or paracetamol (CI if there is nephritis)
   Abdominal pain: paracetamol, rest, supportive care
3. Safety net
4. Discharge

+ follow up 7 days post discharge (repeat urine dip from morning + BP)
+ follow up 1 month → 3. months → 6 months

Question 9

What is the management for henoch schonlein purpura with mild nephritis (normal GFR, mild proteinuria)

Answer 9

1. Refer to nephrology
2. Oral corticosteroid e.g. prednisolone for 1-2 weeks

Consider Immunosuppressants e.g. azathioprine or ACEi/ARB

Question 10

What features suggest significant renal involvement in henoch schonlein purpura

Answer 10

Hypertension – Blood pressure >95th centile on 3 separate readings
Urine albumin creatinine ratio >200mg/mmol
Urine albumin creatinine ratio 100-200mg/mmol and increasing trend
Macroscopic haematuria
Serum albumin

Question 11

What is the management for henoch schonlein purpura with significant renal involvement

Answer 11

1. Admit
2. Contact nephrology
3. Monitor: height and weight, fluid balance, morning urine albumin:creat ratio, 4 hourly BP measurement, low salt diet, mobility encouragement

Question 12

What are the complications of henoch schonlein purpura

Answer 12

Pulmonary haemorrhage
Intussusception
Pancreatitis
GI haemorrhage
Renal failure
End-stage renal disease
CNS complications e.g. headache, seizure
Ocular complications e.g. keratitis, uveitis
Testicular/scrotal involvement

Question 13

What is the prognosis for henoch schonlein purpura

Answer 13

Excellent outcome. Complete recovery occurs in 94% of children
1/3 of patients may have a recurrence within the first 9 months, but subsequent episodes are milder
Increasing age at onset is a risk factor for poor prognosis in children
Joint disease is unlikely to cause a long-term problem
The long term risk of permanent renal impairment in patients with minor urine abnormalities is 1-2%. This rises to ~20% in children with nephrotic or nephritic features.