**2. Inflammation of aorta: "Aortits"**

Large vessel vasculitits such as Takayasu's arteritis and giant cell arteritis, rheumatic and HLA-B27–associated spondyloarthropathies, Behçet's syndrome, and infections such as syphilis, tuberculosis may be the cause of inflammation of aorta, and we must differ‐ entiate these from infected aneurysms when blood culture is negative or infected focus remains unclear. Another disease which we must differentiate is IgG4-related diseases (chronic periaortits).

syndrome. Allergic features such as atopy, asthma, and modest peripheral eosinophilia, along with tumorous swelling in many organs and elevated serum IgG4 levels above the up‐

Infected Aneurysm and Inflammatory Aorta: Diagnosis and Management

http://dx.doi.org/10.5772/54415

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Takayasu's arteritis, also called pulseless disease, involves the ascending aorta and aortic arch, and carotid and subclavian arteries, causing dilations and obstruction at the stage of healing and recurrences. CT angiography revealed the diseased lesion, thickened arterial wall in acute phase and aneurysmal or stenotic lesion in chronic phase [18]. The ultrasonog‐ raphy and MR angiography are also useful. In acute phase, the high signal of T2-weighted and/or STIR MR images and the increased uptake of 18Fluorodeoxy-glucose indicate the presence of active inflammation [19]. The mainstay of therapy for Takayasu's arteritis is glu‐ cocorticoids. Giant cell arteritis (GCA) is a chronic vasculitis of large and medium sized ves‐ sels. The following classification criteria were as follows: 1) Age older than 50 years at onset, 2) Localized headache de novo, 3) Tenderness or decreased pulse of the temporal artery, 4) Erythrocyte sedimentation rate (ESR) greater than 50 mm/h, 5) Biopsy-proven necrotizing

IgG4 -related disease is a newly recognized syndrome of unknown etiology characterized by fibroinflammatory condition, in which tumefactive lesions, a dense lymphoplasmacytic in‐ filtrate rich in IgG4-positive plasma cells. Various symptoms are observed according to the lesions involved, although patients feel well at the time of diagnosis without fever. Seventy percent of patients have elevated serum IgG4 concentrations [17]. CT imaging features of ar‐ terial lesions are characterized by homogeneous wall thickening and enhancement in the late phases after contrast infusion accompanying the increase of connective tissue indicating sclerosing inflammation [21]. This indicates chronic periaortitis, which resembles the infect‐ ed aneurysm with periaortic abscess (Figure 3). Therefore, the diseases should be differenti‐ ated from infected aneurysm by not only the imaging features but also clinical symptoms or

Due to the increase of aged patients with atherosclerosis, more attention should be paid to the endothelial damage of great vessels and an infected aneurysm should be properly diag‐

negative blood cultures. Glucocorticoids typically the first line of therapy.

per limit of normal(>135 mg/dL) are the characteristics of IgG-4 related diseases [17].

**3. Takayasu's arteritis, giant cell arteritis**

arteritis with multinucleated giant cells [20].

**5. Conclusions**

nosed and carefully managed.

**4. IgG4-related diseases: Chronic periaortits**

**Figure 2.** A case of medical treatment of an infected aneurysm. A 75-year-old man with familial hypercholesterolemia, cerebral infarction, and coronary bypass grafting presented with high fever and chest pain. Panel A and B showed a severely calcified ascending aorta. The repeated CE-CT on the 5th day revealed aneurysmal change with protrusion (Panel C), indicating an infected aneurysm. Due to a prohibitive risk of surgery, medical treatment was the choice of him and his family, but the infected aneurysm gradually enlarged despite the control of bacteremia with antibiotics (13th day: Panel D, 24th day: Panel E, and 58th day; Panel F), and he died 2 months after onset.

A detailed history and a careful physical examination are important for the diagnosis and assessment of the extent of vascular lesions. The mean age at onset of Takayasu's arteritis and giant cell arteritis was between 17 and 26 years of age and with 69 years, respectively, primarily in women (about 80 %) [16]. Systemic symptoms are common such as fatigue, weight loss, and low-grade fever are common in these disorders, along with local symp‐ toms, for example, arthralgia, skin lesion (erythema nodosum), and abdominal pains. HLA-B27–associated spondyloarthropathies accompanies with ankylosing spondylitis, reactive arthritis, or inflammatory bowel disease with negative rheumatic factors. Skin and mucosa, ocular system, GI manifestations include abdominal pain, nausea, and diarrhea with or without blood, and/or musculoskeletal and neurological system are involved in Behçet's syndrome. Allergic features such as atopy, asthma, and modest peripheral eosinophilia, along with tumorous swelling in many organs and elevated serum IgG4 levels above the up‐ per limit of normal(>135 mg/dL) are the characteristics of IgG-4 related diseases [17].
