A hernia may become more apparent or bigger when the patient is standing or straining, and may disappear when lying down. It may be associated with discomfort, a pulling sensation, or even pain. If left untreated, a hernia may become larger and irreducible which can be further complicated by obstruction or strangulation of the bowel that is being trapped inside the hernia sac. This happens when the lumen of the bowel passing through the hernia opening (neck) becomes blocked or when the blood supply to the bowel inside the hernia is cut off by the tight narrowing at the hernia neck.
If a complicated hernia is left untreated, the patient will develop vomiting from bowel obstruction or severe pain in the hernia or abdomen from bowel strangulation. When such complications occur, the patient can become very ill and the condition may be potentially fatal.