1.3.2.2 Acquired hernias

In acquired hernias a hernial orifice with hernial sac is formed at certain weak points of the body, example in the abdominal wall when there is a lack of abdominal wall strength or in the vicinity of surgical scars because of incomplete scar formation. One important cause is a defect in collagen metabolism. Since collagen is responsible for the connective and supporting tissues of the body, any disruption in its production leads to connective tissue instability and reduced scar strength. The risk of development of a defect in collagen metabolism, and hence of connective tissue weakness, increases with age. Hernias can also occur due to a sharp rise in the internal abdominal pressure, as in the case of chronic cough due to lung disease, chronic constipation leading to increased pressing during bowel movements or if regularly carrying heavy loads. Other risk factors are pregnancy and overweight. In a few rare cases no reasons can be definitively identified for onset of a hernia.