The esophagus narrows in two primary ways: from issues affecting its inner lining, or from external pressure.
1. Narrowing from Within (Intrinsic Causes):
Processes occurring inside the esophagus can lead to a narrowing of the passageway. This often involves the inner lining, or mucosa, and its ability to stretch when swallowing food.
- Swelling and Inflammation: Conditions causing inflammation, like esophagitis (often due to acid reflux, allergies, or infection), can cause the esophageal lining to swell, reducing the diameter of the esophagus.
- Scar Tissue and Strictures: Repeated injury to the esophagus can lead to the formation of scar tissue. This scar tissue can stiffen and contract, creating a stricture or narrowing. This is a common consequence of chronic acid reflux (GERD).
- Esophageal Webs and Rings: These are thin membranes that can partially obstruct the esophagus. They can be congenital (present at birth) or develop later in life.
- Esophageal Cancer: Tumors growing within the esophagus can physically narrow the space available for food passage.
2. Narrowing from Outside (Extrinsic Causes):
Pressure from neighboring organs or growths can compress the esophagus, causing it to narrow. This is often a gradual process.
- Enlarged Lymph Nodes: Lymph nodes in the chest that become enlarged (due to infection or cancer) can press on the esophagus.
- Tumors in Adjacent Organs: Growths in the lungs, mediastinum (the space between the lungs), or other nearby structures can impinge upon the esophagus.
- Vascular Abnormalities: Abnormal blood vessels, such as an aberrant subclavian artery, can compress the esophagus.
- Thyroid Enlargement (Goiter): A significantly enlarged thyroid gland can sometimes press on the esophagus, especially at the upper portion.
- Hiatal Hernia: While not a direct narrowing, a large hiatal hernia can distort the lower esophagus and make swallowing difficult, sometimes mimicking a narrowing.
These processes usually happen slowly over time.
