Henoch – Schönlein Purpura

Henoch Schönlein Purpura (HSP) is the commonest childhood systemic small vessel vasculitis, most commonly young children (3-10 years). HSP is usually a self-limiting condition; and often occurs following an upper respiratory tract infection. Prognosis is only affected if renal involvement is present.

 

Differential Diagnoses:

– Sepsis (meningococcal)

– Thrombocytopenia

– Leukaemia

– other vasculitides (e.g. Wegener’s, SLE).

HSP presentation

 

Skin (100% involvement) – palpable purpuric rash.

– Often starts as macular-papular erythematous rash before evolving to petechiae and purple, non‐blanching, non‐pruritic urticarial, palpable purpuric lesions.

– Distributed symmetrically, mainly to extensor surfaces of legs and buttocks. Can also be present on arms, face and ears but usually spares the trunk

– Rarely subcutaneous oedemaof the scalp, ears, periorbital area, dorsi of the hands and feet and genitalia (young children) and haemorrhagic bullae.

 

GI tract

– Abdominal pain (may precede rash)

– Vomiting and diarrhoea, bloody stools, periumbilical pain

– Intussusception (about 5% patients)

– Rarely – Bowel perforation, major GI haemorrhage, pancreatitis and gallbladder hydrops.

 

Musculoskeletal

– Arthralgia and peri-articular swelling of joints, typically ankles and knees (synovial effusions typically absent) less commonly wrists, fingers and elbows.

– Decreased range of movement on examination, may be unable to weight bear

– No permanent deformity caused.

 

Renal

– Reported incidences – roughly 20-60% of cases

– Microscopic haematuria (most common), macroscopic haematuria, proteinuria, nephrotic syndrome, nephritis, acute renal failure, hypertension

– Of those who will develop renal involvement:

A) 75-80% of renal involvement occurs within 4 weeks

B) 97% of renal involvement occurs within 12 weeks

– Nephrotic presentation/Acute Renal Failure/Crescentic Glomerulonephritis on biopsy portend poorer prognosis for renal recovery than microscopic hematuria/mild proteinuria.

 

Other clinical manifestations of HSP include:

– Genital – scrotal swelling, painful ecchymotic induration of the scrotum, testicular pain, may mimic testicular torsion, testicular necrosis.

– CNS – headache, encephalopathy, intracranial haemorrhage, seizures, coma, Guillain‐Barre, cortical blindness (all rare)

– Pulmonary – haemorrhage (rare)

– Carditis

– Parotitis

Investigating suspected HSP:

There is no diagnostic test for HSP.

Investigations help to rule out other diagnoses.

 

In all patients:

– Weight and height

– Blood pressure

– Early morning Urinalysis weekly for 12 weeks(if proteinuria present, send for early morning urine protein creatinine ratio weekly)
Early morning (first voided) urinary protein/creatinine ratio(Normal range <20mg/mmol. significant proteinuria is >40, nephritic range is >200) or early morning urinaryalbumin/creatinine ratio(normal range <8mg/mmol, significant proteinuria > 200mg/mmol nephrotic range proteinuria >500mg/mmol)

– Baseline bloods– FBC, clottingand U&E

 

Also consider in some cases:

– Blood film, CRP, blood cultures if unsure of diagnosis or to rule out sepsis

– If evidence of renal involvement (suggested by hypertension, 2+ or greater proteinuria, or evidence of renal impairment on U&Es), check pANCA/cANCA, autoantibody screen, C3/C4 and discuss with a paediatric nephrologist.

There is no indication for renal USS unless specifically advised by nephrology team.

– Surgical referral if any suspicion of intussusception, bowel perforation, or testicular torsion, with investigations as guided by surgical team which may include erect CXR, AXR and USS abdomen.

 

Management:

– Supportive treatment – hydration, nutrition, electrolyte balance, monitor BP

– Analgesia – exercise caution in prescribing non-steroidal anti-inflammatories (contra-indicated in renal involvement, suggested by hypertension, 2+ or greater proteinuria, or evidence of renal impairment on U&Es)

– Information leaflet should be given to parents – with advice on seeking medical attention and training in urinalysis with open access to the ward. Parents should be advised that macroscopic haematuria or 3+ protein for 3 days should warrant urgent ward attendance. Prolonged 2+ protein can be seen in clinic

– If severe GI involvement consider the use of oral steroids (prednisolone 1mg/kg daily up to a maximum of 60mg daily) as a short course

– Discharge if well – pain controlled and no evidence of complications

– Follow up – see below for thel management pathway for outpatient follow up

Further References:

1) Henoch Schonlein purpura. Tizard EJ, Hamilton-Ayres MJ. Arch Dis Child Educ Pract Ed 2008;93:1–8.

2) 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. H Narchi. Arch Dis Child 2005 90: 916-920