Aneurysm of aorta in diseases classified elsewhere

This code represents an aneurysm of the aorta that arises as a manifestation or complication of another underlying disease process, rather than being a primary aortic pathology. It indicates an aortic dilation exceeding normal limits, where the primary etiology is a systemic condition classified elsewhere in ICD-10-CM.

Use this code when documentation clearly links an aortic aneurysm to a specific underlying disease, such as Marfan syndrome, Ehlers-Danlos syndrome, or Takayasu's arteritis. The medical record must explicitly state the causal relationship between the systemic disease and the aortic aneurysm.

• Always sequence the underlying systemic disease first, followed by this code, to accurately reflect the etiology.
• Do not use this code for aneurysms where the underlying cause is not specified or is considered primary to the aorta (e.g., atherosclerotic aneurysm).
• Pay close attention to "Excludes1" notes; specifically, never code this with syphilitic aneurysm (A52.01).