The Evolution in Understanding the Physiological Causes of Dyspnoea in Large Hiatal Herniation: A Narrative Review

The symptomatology of large hiatus hernia (LHH) has been historically poorly understood, with cardiorespiratory symptoms caused by LHH being underappreciated by clinicians. This study reports on the mechanisms of dyspnoea in LHH through a historical review of symptoms and evolved physiological literature, discussing likely causation.

The physiological abnormalities contributing to the development of dyspnoea in LHH were identified through a search of PubMed, Medline, Embase and Cochrane using keywords hiatus (hiatal) hernia, dyspnoea and pulmonary symptoms. A literature review was conducted to identify symptom patterns associated with LHH over time. The established physiological mechanisms have been described.

Multiple mechanisms of dyspnoea were identified over passage of time, including pulmonary gas trapping, cardiac inflow obstruction, pulmonary microaspiration, reduction in pulmonary volumes, parenchymal lung disease and iron deficiency anaemia. Early symptomatic literature was found to infrequently report dyspnoea preoperatively in LHH; however, in recent decades, the frequency of dyspnoea has 'apparently' increased, suggesting improved clinical recognition of the association of LHH and cardio-respiratory symptoms.

Dyspnoea appears to be causally associated with LHH and is likely physiologically multifactorial in individual patients when other causes are excluded as the primary cause.