Hernias occur when the contents of a space inside the body pop out and form a bulge on the outside of that space. An inguinal hernia develops in the groin when a piece of peritoneum, the tissue which lines the abdominal cavity, emerges through the muscular wall of the abdomen to form a bulge beneath the skin. While a direct inguinal hernia bulges out directly through a weak spot in the abdominal muscles, an indirect inguinal hernia passes along a channel known as the inguinal canal. Indirect inguinal hernias are more common and they can develop in men and women of all ages.
Both men and women have inguinal canals, which develop before birth and which may fail to close properly, increasing the risk of hernias developing. In the male fetus, the inguinal canals are the channels along which the testes, or testicles, descend, and in the female they carry ligaments which support the uterus, or womb. Women are at lower risk of developing an indirect inguinal hernia because it is less common for the inguinal canal to fail to close in females.
Anything which increases abdominal pressure can make an indirect inguinal hernia more likely to develop. Strenuous activities, such as lifting heavy weights, or persistent coughing may increase the risk. Being overweight, pregnant or constipated can also make hernia development more likely. An indirect inguinal hernia may cause no symptoms or sometimes a bulge may appear in the groin, which might be painful and could increase in size on coughing. It may be possible to push the hernia back into place, in which case it is described as reducible.
There is a risk that an indirect inguinal hernia may become strangulated. This means that the blood supply to the hernia contents becomes cut off. As the hernia contents typically consist of a piece of peritoneum, sometimes together with a portion of intestine, the consequences could be serious. If an indirect hernia is not reducible and becomes suddenly very painful, medical help should be sought immediately, as the strangulated gut could die off in a matter of hours.
Treatment of an indirect inguinal hernia usually requires surgery, although a small, painless hernia may be monitored if it is not increasing in size. Surgery generally consists of returning the hernia contents to the abdominal cavity before repairing and reinforcing the weak point through which the hernia emerged. Sometimes a piece of mesh is used to strengthen the area of weakness. The outlook following surgery is usually positive.