Aetiology

The aetiology of a sliding hiatal hernia is multifactorial. Most cases are thought to be acquired rather than congenital.

Three possible mechanisms have been proposed to explain the cause for the displacement of the gastro-oesopahgeal junction upward into the thorax:

• increased intrabdominal pressure
  • seen in large ovarian cysts, pregnancy, obesity, and the wearing of tight corsets
  • causes a progressive increase in intra-abdominal pressure, which promotes herniation
• oesophageal shortening - which will pull more of the stomach into the chest
  • due to oesophageal spasm and fibrosis from reflux
  • accentuation by excessive swallowing
• widening of the diaphragmatic hiatus
  • muscular degeneration - around the lower end of the oesophagus and the fundus of the stomach
  • decreased elasticity of the crus (1)

Scoliosis, kyphosis, and pectus excavatum are considered as predisposing factors (2).

In infancy, hiatus hernias are nearly always of the sliding type.

Reference:

• (1) Weber C et al.Hiatal hernias: a review of the pathophysiologic theories and implication for research. Surg Endosc. 2011;25(10):3149-53
• (2) Roman S, Kahrilas PJ. The diagnosis and management of hiatus hernia. BMJ. 2014;349:g6154