What is a characteristic of an inflammatory aortic aneurysm?

Inflammatory Aortic Aneurysm Characteristics

Inflammatory aortic aneurysms may present with abdominal pain in the absence of rupture, which is a key distinguishing feature from non-inflammatory aneurysms. 1

Clinical Presentation and Pathology

Inflammatory abdominal aortic aneurysms (IAAA) represent 5-10% of all abdominal aortic aneurysms and have several distinct characteristics:

• Pain presentation: Unlike typical atherosclerotic aneurysms, patients with inflammatory AAAs are usually symptomatic with back or abdominal pain even without rupture 1
• Pathological features: IAAAs are characterized by:
  • Marked thickening of the aneurysm wall 1
  • Dense periaortic fibrosis involving adjacent organs 2
  • Extensive retroperitoneal fibrosis 3
  • A characteristic "mantle sign" on CT imaging (seen in 73-100% of cases) 4

Laboratory and Imaging Findings

• Inflammatory markers: Most patients have elevated erythrocyte sedimentation rate (ESR) or other serum inflammatory markers 1
• Imaging characteristics:
  • Less likely to show intimal calcifications compared to atherosclerotic aneurysms
  • Mural thrombosis is less common than in atherosclerotic aneurysms
  • Periaortic soft tissue stranding and inflammatory response are common findings 5

Rupture Risk and Management

Contrary to option (b) in the question, inflammatory AAAs appear less likely to rupture than atherosclerotic AAAs, though surgical intervention is still recommended once the diameter exceeds 5.5 cm 1.

Medical Management

• First-line treatment: Corticosteroids or immunomodulatory therapies 5
• High-dose glucocorticoids with a prolonged taper over 1-2 years is recommended 5
• Smoking cessation is essential as male sex and smoking are even stronger risk factors for inflammatory AAAs than for atherosclerotic AAAs 1
• Experts recommend treating to clinical remission before elective repair whenever possible 5

Surgical Management

• Surgical repair is technically challenging due to dense adhesions 3
• Endovascular aneurysm repair (EVAR) has shown promise with:
  • Lower perioperative mortality compared to open repair
  • Reduction in aneurysmal sac size and periaortic fibrosis 6, 4
  • However, EVAR is associated with more post-operative progression of inflammation (17% vs. 0.4%) 4

Important Distinctions

• Option (a) is incorrect: There is no evidence in the literature provided that inflammatory AAA repair is associated with a higher incidence of graft infection
• Option (c) is partially correct but imprecise: IAAAs lead to marked thickening of the aneurysm wall and periaortic fibrosis, but not necessarily "circumferential" thickening of the aorta itself 1
• Option (d) is correct: Abdominal pain in the absence of rupture is a key clinical feature of inflammatory AAAs 1

Clinical Pearls

• The classic triad of chronic abdominal/back pain, weight loss, and elevated inflammatory markers is highly suggestive of IAAA but rarely all present 4
• Close follow-up after repair is necessary to monitor the inflammatory process, with suggested 3-6 monthly monitoring of renal function and ESR for 24 months post-repair 3
• The left-flank extraperitoneal surgical approach may be advantageous for repair of inflammatory AAAs to avoid complications from dense adhesions 2