Chapter 13: The Vascular System

NONINFECTIOUS VASCULITIS

The term vasculitis refers to inflammation of blood vessels. There are various classification schemes for noninfectious vasculitis, based on the sizes of the blood vessels typically involved and the pathology of the lesions (Table 13-1). Takayasu disease is the most important large vessel vasculitis in children. Kawasaki disease, polyarteritis nodosa, and primary central nervous system (CNS) vasculitis of childhood are vasculitides that primarily involve mediumsize vessels. Examples of small vessel vasculitis include Henoch-Schönlein purpura, Wegener granulomatosis, Churg-Strauss syndrome, and microscopic polyangiitis. There is considerable variation in the organ systems most prominently affected by the various vasculitides. Constitutional symptoms, fever, and skin lesions are common with these disorders.¹

Takayasu Arteritis (Occlusive Thromboarthropathy)

Takayasu arteritis (Takayasu disease) is a rare idiopathic chronic inflammatory arteritis that causes thrombosis, stenosis, dilation, and aneurysm formation in the pulmonary arteries, aorta, and major aortic branch vessels. Although the pathogenesis is incompletely understood, Takayasu arteritis apparently is an autoimmune process. There is granulomatous inflammation of the involved vessel, a result of the deposition of autoimmune complexes in areas of vessel wall permeability. The inflammation damages the adventitia and media, and leads to subsequent reactive proliferation of the intima and adventitia. Ultimately, there is progression to concentric mural thickening and calcification; all layers of the arterial wall are involved. The aortic arch and its branches are the most common locations of symptomatic disease in patients with Takayasu arteritis. Other potential sites of involvement include the descending thoracic aorta, abdominal aorta, renal arteries, and splanchnic arteries.²

The clinical manifestations of Takayasu arteritis are predominantly caused by vascular stenoses. Symptomatic aneurysms can also occur. The clinical onset of Takayasu arteritis in children is usually during the second decade of life; 90% of patients are younger than 30 years at the time of presentation. The onset may be insidious or, less commonly, fulminant. Potential early symptoms in children include dyspnea and hemoptysis. Hypertension is common, usually as a result of renovascular stenosis. Carotid artery involvement can result in syncope or other neurological symptoms. Aortic regurgitation can occur in patients with a dilated aortic root. Patients with Takayasu arteritis are at risk for osteoporosis, either as a complication of the disease or as a side effect of therapy. Takayasu arteritis most often occurs in young ...