Vasculitis

Published on 23/06/2015 by admin

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Last modified 23/06/2015

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11.5 Vasculitis

1 The most common childhood vasculidites are Henoch–Schönlein purpura (HSP) and Kawasaki disease.

2 In HSP persistent renal disease occurs in a minority of children. Repeat urinalysis is recommended at intervals until resolution of symptoms, as nephritis may be delayed.

3 Kawasaki disease should be considered in all children with unexplained high fever for more than 5 days. All features may not be present simultaneously and a history of mucositis, cervical lymphadenopathy, conjunctivitis, rash and peripheral cutaneous manifestations should be specifically sought.

4 Vasculitis may occur secondary to a primary underlying disease, infections, drug reaction or malignancy and should be excluded.

5 Vasculitis should be considered in children with a non-specific febrile illness and exanthem without explanation that do not resolve as would be expected with a self-limited infectious illness.

Introduction

Childhood vasculitides are a group of disorders characterised by inflammation of blood vessels. Vasculitis is the common end point of several different disease processes and no one mechanism can explain the pathogenesis in this heterogeneous group of conditions. Distinguishing a primary vasculitis from a secondary underlying disease or from conditions that mimic vasculitis can be difficult. Most forms of vasculitis are rare in childhood. Henoch–Schönlein purpura (HSP) and Kawasaki disease (KD) are the two commonest childhood vasculitides.

Clinical presentation

The presentation varies widely according to the size of the affected blood vessel and the extent and nature of organ involvement. Constitutional symptoms are common to all vasculitides and include fever, weight loss, malaise, irritability and arthralgias. Skin manifestations are frequent and often give a clue to the size of the vessel involved; lesions are commonly purpuric but may be urticarial, ulcerative, vesicular or resemble erythema multiforme. In severe vasculitis, vessel destruction leads to tissue infarction, and can result in ischaemia and gangrene.

Classification

The primary vasculitic disorders can be divided according to the size of the vessel involved.

Small vessel vasculitis

HSP, Wegener’s granulomatosis and Churg–Strauss syndrome predominantly involve small vessels; the latter two conditions are extremely rare in childhood.

Henoch–Schönlein purpura

HSP is the commonest vasculitis in childhood. It is immune mediated, associated with IgA complex deposition in tissues, and though several infective agents, drugs and immunisation have been implicated, the cause is unknown.

Clinical presentation

HSP is characterised by palpable purpura which is mandatory for diagnosis with one or more of the following: diffuse abdominal pain, arthritis or arthralgia, renal involvement, or a tissue biopsy showing predominantly IgA deposition.

Skin lesions begin as maculopapules that initially blanch and develop to palpable purpura, which may include macules, papules, vesicles, bullae, nodules and urticaria. Lesions are symmetrical and maximal on lower limbs and buttocks and may be painful. Local angio-oedema of face, hands, feet, back, scrotum and perineum is common in younger children.

Arthritis occurs in up to 80%, with one or more joints involved, and resolves leaving no residual joint deformity. Large joints of the lower extremity are usually affected but upper extremity joints may also be involved.

Gastrointestinal symptoms are common and include colicky abdominal pain, vomiting and bloody diarrhoea. Over half of patients have occult blood in stools. Intussusception (usually ileoileal) is the most common serious gastrointestinal complication and results from oedema and haemorrhage in the bowel wall acting as a lead point. Ultrasound is recommended when suspected, as contrast enema will not detect ileoileal pathology.

Some children present with isolated abdominal symptoms or arthritis and the diagnosis may only become apparent when the rash develops days to weeks later. Nephritis occurs in about half and may be delayed for up to 4 or more weeks. Other serious though uncommon conditions can occur including orchitis cerebral involvement, including seizures.

Investigations

There is no diagnostic test for HSP; the diagnosis is clinical but may be difficult in the absence of rash. Blood pressure measurement, urinalysis and renal function assessment at presentation are required in all patients. Renal biopsy is reserved for patients with nephritis complicated by nephrotic syndrome, hypertension or renal failure. Throat swab, C3/C4 and ASOT may be useful in distinguishing poststreptococcal arthralgia from HSP where the clinical picture is not full-blown.

Prognosis

It is generally a self-limited condition but can recur in one-third of patients. Resolution of symptoms occurs over a period of weeks. A small percentage of children develop persistent renal disease, with about 0.1% developing serious renal disease. Those with isolated haematuria and proteinuria without renal insufficiency completely recover.

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