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Autoinflammatory syndromes, formerly known as periodic fever
syndromes, are defined as recurrent attacks of often unprovoked
systemic inflammation that are related to a lack of adequate regulation
of the innate immune system.1-3 Unlike autoimmune
diseases, these conditions are not generally marked by autoantibodies
or autoreactive T cells. Many of these syndromes have a genetic
etiology3,4 (eTable 209.1) involving
the excessive production and activity of interleukin (IL)-1β.5 The
conditions are no longer known as periodic fever syndromes, 6-8 because
most are not truly periodic nor is fever a necessary feature.
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As understanding of the pathogenesis of autoinflammatory syndromes
increases, so does the spectrum of conditions that may be included
within this category. Thus, systemic juvenile idiopathic arthritis,
genetic inflammatory granulomatous diseases (early onset sarcoidosis
and Blau syndrome) and Behçet disease (eTable
209.2) are now considered to be autoinflammatory disorders,
although this chapter will be limited to conditions that do not
fall into other diagnostic categories.
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These syndromes should be suspected in patients, mainly young
children, with recurrent fever unexplained by infections and/or
with episodic symptoms in various systems, especially the skin,
gastrointestinal tract, joints, and eyes. A complete history and
physical examination are crucial, and often careful determination
of the organ systems involved, age of onset, length of attacks,
intervals between attacks, and triggering events will allow the
correct diagnosis to be suspected ...