Definition Macrophage activation syndrome (MAS) is a severe, potentially fatal complication of rheumatic diseases caused by excessive activation and expansion of macrophages and T cells, leading to an overwhelming inflammatory reaction. The main manifestations of MAS include fever, hepatosplenomegaly, lymphadenopathy,…
Pediatric sarcoidosis encompasses a spectrum of childhood granulomatous inflammatory conditions, with the hallmark being the presence of noncaseating epithelioid giant cell granulomas in a variety of tissues and organ systems. The finding in 2001 of a mutation in the nucleotide-binding…
Autoinflammatory Bone Diseases Overview Autoinflammatory disorders (covered extensively in Chapter 39 ) result from aberrant and/or spontaneous activation of components of the innate immune system. , At least initially, they occur in the absence of high titer autoantibodies or autoreactive…
Repeated febrile episodes lasting for a few days to a few weeks are common in young children. Infection is the most common etiological factor. However, after infectious causes and malignancy have been excluded, rheumatic illnesses enter the differential diagnosis. Unexplained…
Introduction and Historical Review In 1937 the Turkish dermatologist Hulusi Behçet described the syndrome that bears his name, comprising the clinical triad of aphthous stomatitis, genital ulceration, and uveitis. Subsequently Adamantiades defined the thrombophlebitis and Matteson identified even earlier reports…
Takayasu Arteritis In 1908 the Japanese ophthalmologist Takayasu and his colleagues described the association of retinal vessel abnormalities with absent wrist pulses. Takayasu arteritis (TA) is a rare, chronic, relapsing granulomatous large-vessel vasculitis affecting the aorta, its major branches, and…
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of vasculitides characterized by small- to medium-sized blood vessel inflammation, clinically overlapping features, and the presence of ANCA. This group comprises granulomatosis with polyangiitis (GPA), formerly Wegener granulomatosis; microscopic polyangiitis (MPA);…
Historical Background Kawasaki disease (KD) is one of the most common vasculitides of childhood. This vasculitis bears the name Kawasaki disease because of the highly detailed description of this illness in 50 children by Tomisaku Kawasaki in 1967. Scattered case…
Introduction Polyarteritis nodosa (PAN) was first described by Kussmaul and Maier in 1866. The original and subsequent descriptions identified the pathological features of necrotizing arteritis with nodules along the walls of medium and small muscular arteries, leading to thrombosis or…
Necrotizing vasculitis that affects small blood vessels (especially the postcapillary venules, capillaries, and arterioles) is often caused by immune complex deposition and may show leukocytoclastic vasculitis on histology ( Fig. 33.1 and Box 33.1 ). , The term leukocytoclasis refers…