CHAPTER 101 ■ RHEUMATOLOGIC EMERGENCIES THERESA M BECKER, MELISSA HAZEN GOALS OF EMERGENCY CARE Pediatric rheumatologic conditions are rare and are typically chronic conditions with an indolent onset rather than acute conditions likely to bring a child to the emergency department (ED) Nonetheless, there are several reasons why children with rheumatologic conditions may present to the ED First, the majority of rheumatologic conditions involve a myriad of signs and symptoms affecting many organ systems, which may bring an exasperated family to the ED searching for an elusive diagnosis Second, arthritis, lupus, and vasculitis (especially Kawasaki disease [KD]) may have acute and life-threatening complications that require rapid initiation of appropriate therapy Finally, the treatment of rheumatologic disorders is becoming more sophisticated and more specialized, involving combinations of anti-inflammatory, immunosuppressive, and biologic agents, with a wide spectrum of undesired effects Often a key challenge is differentiating the effects of underlying disease from the effects of therapy Thus, the goals of emergency care are the prompt recognition of these conditions, and the expeditious use of medical therapy to treat the complications of the diseases and the side effects of drug therapy KEY POINTS Kawasaki disease requires treatment in the first 10 days of the illness in order to achieve an optimal clinical outcome Many rheumatologic conditions are treated with medications that suppress the immune system Stress doses of corticosteroids may be required for fever and other acute illnesses Childhood vasculitis may affect any organ system and may present indolently or acutely with life-threatening end-organ involvement Juvenile idiopathic arthritis subtypes are varied in their presentation and associated with different articular and extra-articular complications Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) or reactive HLH should be considered in an ill child with persistent fever, organomegaly, and neurologic symptoms with systemic inflammation, cytopenias, and/or liver dysfunction