Paediatric vasculitis

Introduction

• Consider in all children with non-specific febrile illness and exanthem that does not resolve
• Hsp and kawasaki are most common
• Clinical presentations
  • Constitutional symptoms – fever, weight loss, malaise, irritability and arthalgia
  • Skin lesions

Vasculitis

• Small vessel vasculitis
  • HSP
  • Wegener’s granulomatosis (very rare in childhood)
  • Churg-strauss (very rare in childhood)
• Medium vessel
  • Kawasaki
  • Polyarteritis nodosa
• Large vessel
  • Takayasu

Henoch-schonlein purpura

• Most common vasculitis of childhood
• Mostly age 2-8. Mean age 4-7 and predominant male
• Infants have milder disease and <2yo are less likely to have nephritis or abdominal pain
• 50% of cases have preceding viral urti. Also associated with immunisation and medications
• Leukocytoclastic vasculitis affecting small vessels (arterioles and venules)
• IgA complex deposition in tissues
• Classical presentation
  • Palpable purpura: Initially blanching. Can be bullous or urticarial. Need normal platelet count by definition (as per cameron)
  • Arthritis/arthalgia (50-75%): Resolves with no joint deformity.
  • Abdominal pain (50%)
  • Renal involvement (25-50%)

• Can progress of days to weeks
• All patients have purpura but may not be initial complaint (75% of the time it is)
• Pulmonary and neurological sequelae are rare but can be life-threatening
• Intussusception (ileo-ileal) is the most common serious abdominal complication. Occurs as swelling and haemorrhage act as lead point.

Differential

• Viral infections
• Meningococcal
• Kawasaki: Unremitting fever with maculopapular rash prominent on lower extremities. 
  • Rash does not appear in crops and is not associated with arthritis
  • Eye findings not seen in hsp
• Bacteraemia e.g. s. pneumoniae, H. influenzae
• Infective endocarditis
• Infectious mononucleosus
• ITP
• Leukaemia
• cough or vomit induced petechiae

Investigations

• Dipstick Urinalysis
  • All that is required for classical HSP (as per RCH)
  • (Cameron recommends U&E and FBC in all children)
  • Check for macroscopic haematuria or more than trace proteinuria
• If HTN, or positive dipstick
  • Urine MCS + Protein:Creatinine ratio
  • UEC and Serum Albumin
• If diagnosis unclear
  • FBC, U&E, albumin, BC, urine culture, Abdominal imaging, throat swab, ASOT, ANA, anti-ds DNA, ANCA, C3/C4 if renal involvement and unclear diagnosis
• Skin biopsy
  • Neutrophil infiltration in and around dermal vessels
• Renal biopsy
  • Focal or diffuse mesangial proliferation +- glomerular crescent formation
  • Immunofluorescence shows diffuse mesangial deposition of IgA and C3

Management

• If unwell, treat as for meningococcal
• If well and not clear HSP picture, blood tests should be performed
  • If all of the below met and observed for 4 hours, can be discharged with follow-up
    • Well
    • WCC 5-15
    • CRP <8
    • No deterioration or progression of rash over 4 hours

• Mild pain
  • Paracetamol +- ibuprofen
  • Bed rest and elevation of affected areas of subcutaneous oedema
• Moderate-Severe pain
  • Steroids reduce duration of abdominal and joint pain
  • Do not reduce long-term renal complication rate
  • Prednisolone 1-2mg/kg/day while symptoms persist and wean if necessary

• Indications for admission
  • Serious abdominal complications
  • Severe debilitating pain
  • Unable to ambulate
  • Severe renal involvement
  • Neurological or pulmonary involvement

Discharge advice

• In the absence of renal disease, resolves over 4 weeks with rash being last symptom to remit
• Joint pain usually resolves within 72 hours
• Uncomplicated abdominal pain usually resolves in 24-48 hours
• 1/3 of patients have at least one recurrence, usually within first 4 months
• Each subsequent episode tends to be less severe
• 90% of those that develop renal complications do so within 2 months and 97% within 6 months
• 5% develop some renal disease
• 0.1 (RCH)-1% (Cameron) develop serious renal disease/ESRD

Follow-up

• BP and early morning urinalysis
  • Weekly for first month
  • Fortnightly weeks 5-12
  • Single reviews at 6 and 12 months
  • Return to start if any recurrence
• If all normal at 12 months, no follow-up required

Kawasaki disease

• Medium vessel with predilection for coronary vessels
• 2^nd most common vasculitis of childhood
• Most common in japanese and mainly children <5 (85%). Peak age 18-24 months
• <6mo and >5yo is less common but more likely to suffer coronary artery aneurysm
• 15-25% get coronary artery aneurysms if untreated which may lead to IHD and sudden death

• Classical presentation
  • Fever >5 days with 4/5 of below OR fever with coronary artery aneurysm and 3 other findings
    • Cervical adenopathy: Mostly unilateral and tender with one node >1.5cm
    • Bilateral non-suppurative conjunctival injection with perilimbal sparing
    • Polymorphous rash (maculopapular, multiforme, scarlatiniform)
    • Peripheral cutaneous or perianal erythema, swelling or induration
      • Desquamation 2-3 weeks after onset
    • Mucous membranes changes (lip fissures, pharyngitis, strawberry tongue)
• May be atypical if not meeting all criiteria (mosre likely to get coronary artery aneurysm)

Clinical features

• Fever normally >39 with minimal response to antipyretics
• Extreme irritability in toddler with persisting fever of unclear origin should always prompt consideration
• May have pericarditis, myocarditis, valvular involvement
• Aseptic meningitis
• Arthritis
• Sterile pyuria
• Uveitis
• Hepatitis
• Hydrops of gallbladder

Pitfalls

• <6 mo with persistent fever and irritability without clear cause
• Prolonged fever and unexplained aseptic meningitis
• Prolonged fever and cervical adenitis not responding to oral antibiotics

Differential diagnosis

• Group A strep – Pharyngitis, scarlet fever, acute rheumatic fever
• EBV, adenovirus
• Systemic juvenile idiopathic arthritis
• Sepsis or toxic shock syndrome
• SJS
• Drug reaction

Investigations

• FBC, CRP, ESR, Chem20, BC, urinalysis, ECG +- CSF
• Left shift, anaemia, thrombocytosis (week 2-3), mild hepatitis
• CSF – mononuclear pleocytosis but sterile
• Urine – Mild proteinuria/pyuria
• If atypical, nromal platelet, ESR and CRP at day 7 makes diagnosis unlikely
• Leukopaenia, lymphocyte predominance and thrombocytopaenia in absence of DIC also make diagnosis less likely
• Echo – should be done in all children.

Incomplete Kawasaki (AHA)

• CRP <8 and ESR <20
  • Serial clinical and lab re-evaluation if fever persists
  • Echo if desquamation occurs
• CRP >8 and ESR >20
  • 3 or more of: anaemia, Plt >450 after day 7 of fever, Albumin <30, raised ALT, WCC >15 or urine >10 WBC/HPF or positive ECHO = TREAT
  • If not meeting above criteria, serial clinical and lab re-evaluation if fever persists and echo if desquamation occurs

Management

• Combined aspirin + IVIG reduces rate of aneurysm from 25% to 5% if delivered in first 10 days (still give if ongoing inflammation after day 10)
• High-dose aspirin initially then antiplatelet dose after defervescence
  • Consider Reye syndrome (rapidly progressive encephalopathy with hepatitis)
• May repeat IVIG if not responding (persistent fever)
• Steroids are controversial
  • Consider for high risk patients as suggested by shock, <12mo, asian, ALT >100, Albumin <30 or evidence of cardiac involvement at presentation
• Long-term
  • Follow-up echo, stress testing in adolescence and angiography may be indicated
  • Long-term antiplatlet or anticoagulation may be necessary

Prognosis

• If no cardiac involvement, complete recovery expected
• Worse prognosis if aneurysm >8mm

Last Updated on November 22, 2021 by Andrew Crofton