Aortic aneurysm

What it means

Aortic dilatation refers to a dimension that is greater than the 95th percentile for the normal person age, sex and body size. In contrast, an aneurysm is defined as a localized dilation of the aorta that is more than 150 percent of predicted (ratio of observed to expected diameter 1.5 or more). Aneurysm should be distinguished from ectasia, which represents a diffuse dilation of the aorta less than 50 percent of normal aorta diameter.

Aneurysm is considered a severe (pathological) form of dilatation of a segment of a blood vessel. In clinical practice, dilatation and aneurysm are occasionally used interchangeably. In this subhierarchy, we therefore use aneurysm as the primary label and list dilatation as a broad synonym.

In everyday care

Most people with this sign do not have a rare disease — it appears in common conditions far more often. These general reference pages cover the same topic:

Rare diseases that can present with this30

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Aortic dilatation · Enlarged aorta