What Causes Hiatal Hernia
Hiatal hernias develop primarily from widening of the esophageal hiatus in the diaphragm, combined with defects in the phrenoesophageal membrane, allowing abdominal contents to herniate into the thoracic cavity. 1
Primary Causative Mechanisms
Anatomical Defects
- The esophageal hiatus widens, which is the fundamental anatomic change that permits the gastric cardia and gastroesophageal junction to migrate above the diaphragm in Type I sliding hernias (90% of cases) 1
- Defects in the phrenoesophageal membrane are particularly important in paraesophageal hernias (Type II), where this membrane failure allows the gastric fundus to herniate while the gastroesophageal junction remains in normal position 1
- The diaphragm becomes weakened, creating the pathway through which stomach and other abdominal organs can protrude into the chest cavity 2
Risk Factors Contributing to Development
Age-related changes are a major contributor, as hiatal hernias are strongly associated with advancing age and the progressive weakening of diaphragmatic structures 3
Obesity significantly increases risk by creating chronic increased intra-abdominal pressure that stresses the hiatus over time 2, 3
Clinical Context
While the exact mechanism of hiatal hernia formation involves these anatomical failures, it's important to recognize that:
- The condition can occur in patients of any age and gender, though elderly patients are at highest risk 2, 3
- The herniation represents an acquired diaphragmatic defect rather than a congenital condition in most cases 1
- In severe Type IV hernias, the defect becomes large enough to accommodate not just stomach but also colon and spleen 1
Common pitfall: Don't assume all hiatal hernias are symptomatic—many are incidental findings, with asymptomatic hernias becoming symptomatic at only 1% per year 4