IgG4-related arteritis and periarteritis is a form of IgG4-related cardiovascular disease, in which multi-vessel involvement is very common.
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Epidemiology
IgG4-related arteritis and periarteritis predominantly affect men above 60 years of age 1.
Associations
Conditions associated with IgG4-related arteritis include 1:
- inflammatory aneurysm
- pericarditis
- other organ involvement: pancreas, salivary glands, lymph nodes etc.
Clinical presentation
Clinical manifestations can be nonspecific and diverse including fever, abdominal pain, backache and/or weight loss. Biochemically IgG4-related cardiovascular disease is characterized by an elevated serum IgG4 concentration of ≥1.35 mg/L 1-4.
Complications
IgG4-related arteritis of the non-coronary arteries to the following conditions 1-4:
- aneurysmal changes
- thrombus formation and stenosis or occlusion
- pulmonary hypertension
Pathology
IgG4-related arteritis and periarteritis feature a fibrosclerotic inflammation of the adventitia characterized by a lymphoblastic infiltration. Involvement of the tunica media is less extensive 1-3.
Location
Many patients have involvement of multiple vascular territories. Arteries besides the aorta and coronary arteries that can be affected by IgG4-related disease include 1-3:
- common iliac arteries and external iliac arteries (most common)
- brachiocephalic trunk and subclavian arteries
- carotid arteries
- renal arteries
- celiac trunk and superior mesenteric artery
- pulmonary arteries
In addition, small and medium-sized arteries can be affected including:
- splenic artery
- other first branches of the aorta as lumbar arteries
Macroscopic appearance
Macroscopically IgG4-related arteritis features an inflammatory thickening of the adventitia with a red to brownish color 1.
Microscopic appearance
The microscopic appearance of IgG4-related cardiovascular disease includes the following histological features 1:
- lymphoplasmacytic infiltration of IgG4-positive plasma cells
- a storiform fibrotic pattern of radially arranged collagen fibers rough tissue
- obliterative phlebitis
Immunophenotype
Immunohistochemistry stains should express IgG4 and CD138.
Radiographic features
General radiographic features of IgG4-related disease includes the following 1,2:
- inflammatory vasculitis
- aneurysmal change
- pseudotumor formation
CT
CTA with multiplanar reconstructions is recommended for the evaluation of IgG4-related cardiovascular disease. Delayed contrast enhancement might aid in the differentiation of inflammatory wall-thickening from mural thrombus formation 1-3.
CT imaging features include 1-3:
- diffuse or partial arterial mural thickening (>2 mm)
- homogenous wall enhancement especially in a delayed phase
- absence of calcifications
- associated luminal stenosis
- partial aneurysmal dilatation
MRI
MRI can help in the visualization of mural thickening and edema as well as in the evaluation of concomitant aortic disease. For the assessment, black-blood imaging might be beneficial.
Signal characteristics
- T1 black-blood: hypointense
- T2FS/STIR-black-blood: hyperintense
- T1 C+ (Gd): perivascular delayed enhancement
Nuclear medicine
PET-CT
PET-CT shows abnormally increased FDG uptake in the vessel wall and can provide important information in respect to disease activity 1-3.
Radiology report
The radiological report should include a description of the following features:
- location and extent of the affected vessels
- aneurysmal dilatations
- thrombus formation
- concomitant stenosis
- pseudotumor formation
- aortic involvement
- involvement of other organs
Treatment and prognosis
IgG4-related disease responds to corticosteroid therapy. Another agent which has been used in the treatment is Rituximab 1,4.
History and etymology
A general concept of IgG4 related autoimmune disease was first described in 2003 by Terumi Kamisawa and colleagues 1,6.
Differential diagnosis
The differential diagnosis of IgG4 related coronary disease include the following 3,4:
- giant cell arteritis
- Takayasu arteritis
- Kawasaki disease
- rheumatoid arthritis
- systemic lupus erythematosus
- ANCA associated vasculitis