Pediatric emergency medicine trisk 2958 2958
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commonly, children may have cardiac disease (pericarditis, cardiomegaly, EKG
changes, myocardial infarction) or pulmonary involvement (diffuse infiltrates,
pulmonary hemorrhage, or hemothorax).
Clinical Assessment
The patient should be examined carefully for signs of end-organ involvement,
including blood pressure elevation, abdominal tenderness, arthritis, CNS disease (e.g.,
hemiparesis), cardiac disease (e.g., pericarditis, myocardial infarction), and pulmonary
involvement. Urinalysis is a useful marker for renal involvement.
Laboratory findings in polyarteritis are nonspecific but suggest both acute and
chronic inflammation. Most children have white blood cell counts higher than
15,000/mm3, hemoglobin <10 g/dL, broadly elevated acute-phase reactants, and
hypergammaglobulinemia. Complement levels are usually normal or increased, and
ANA and RF levels are elevated only slightly, if at all. Some children have evidence of
ANCAs, although other autoantibodies are usually absent.
Diagnosis of PAN generally requires tissue confirmation. Acute necrotizing
inflammation of small- and medium-sized arteries is demonstrable in renal, cutaneous,
muscular, or GI tissues. At times, biopsy may not be practical, and angiographic
visualization of aneurysms may provide an acceptable alternative. Other findings
include visceral perfusion defects, especially in the kidneys, development of collateral
arteries, and a “beaded” appearance of involved vessels as a result of alternating areas
of stenosis and dilatation. Performance and interpretation of these studies requires the
expertise of a radiologist experienced in pediatric angiography.
Management
The prognosis in PAN is better in patients with less disease-related organ damage, so
therapy should be initiated as early as possible. The initial management of PAN
includes corticosteroids (generally divided doses of prednisone, 2 mg/kg/day, to a
maximum of 60 mg daily). Rash and constitutional symptoms improve first, followed
by control of end-organ involvement. Pulse doses of methylprednisolone (30 mg/kg in
50 mL of 5% dextrose in water by IV infusion over 1 to 2 hours, maximum dose 1000
mg) may offer an alternative for the treatment of acute exacerbations, provided that
blood pressure and cardiac rhythm are closely monitored.
Cutaneous PAN may require lower doses of steroids to suppress disease activity, or
alternative steroid-sparing agents such as methotrexate, dapsone, or colchicine may
adequately control the rash. In contrast, children with systemic PAN may not tolerate a
reduction in their steroid dosage or may not respond adequately to steroids. In such
cases, the addition of immunosuppressive agents (e.g., oral or IV cyclophosphamide) or
biologic response modifiers (e.g., infliximab or rituximab) may improve the outcome
or allow tapering of steroids.
