Most hernias occur when part of the intestine or peritoneum pushes through a gap in the abdominal wall. The peritoneum is the membrane that lines the abdominal cavity and (completely or partly) encloses most of the organs in the abdomen. The protruding pouch, called the hernia sac or hernial sac, may contain part of the peritoneum, intestine or stomach, as well as belly fat. A bulge can usually be seen from the outside. Whether or not a hernia causes problems will depend on where it is and how big it is.
These are the most common types of hernias:
- Inguinal hernias: occur at a weak spot in the groin near the inguinal canal, above the inguinal ligament. This is the most common kind of hernia. They usually affect men.
- Femoral hernias : occur in the upper part of the thigh near the groin, in a place called the femoral canal below the inguinal ligament. They mainly affect women.
- Incisional hernias: occur through previously made surgical incisions (cuts). The abdominal wall is weaker there, so hernias are more likely.
- Umbilical hernias: arise at a weak point in the abdominal wall near the belly button (navel). They are most common in babies and overweight adults.
- Epigastric hernias: where tissue pokes through a gap in the abdominal wall between the breastbone and the belly button.
- Diaphragmatic hernias: occur if one of the openings in the diaphragm widens. It is normal to have openings in your diaphragm. Blood vessels, nerves and organs like your food pipe pass through them. But if the tissue surrounding an opening loosens, the peritoneum or parts of the stomach might bulge into the chest area from the abdomen. This kind of hernia can’t be seen from the outside. Unlike the types of hernia mentioned above, it is what is known as an “internal hernia.” The most common kind of diaphragmatic hernia is called a hiatus hernia. This is where part of the stomach protrudes through the opening (hiatus) that the food pipe passes through.
Most hernias don’t go away on their own. If treatment is needed, the only treatment option is surgery. One exception is umbilical hernias in babies. These usually go away on their own within the first two years of the baby’s life.
The most common types of hernia
Most hernias can be felt or even seen as bulges. They don’t all cause problems, though. But they might cause pain, burning, a feeling of pressure or a pulling sensation, especially during physical strain. Some people only have symptoms when they tense their abdominal (tummy) muscles a lot.
If the section of the intestine in the hernia becomes constricted, making it difficult for the contents of the intestine to pass, people may have problems with their digestion. In men who have an inguinal hernia, tissue may poke into a scrotum, making it swell a lot (scrotal hernia).
Severe or sudden new pain in the area of the hernia, or nausea and vomiting in addition to pain, could be signs that the hernia sac has become blocked or cut off. This can lead to serious complications such as peritonitis (inflammation of the peritoneum).
Large, clearly visible hernias are very unpleasant and can be quite distressing.
The symptoms caused by diaphragmatic hernias are different to the symptoms caused by hernias that poke out through gaps in the abdominal wall (abdominal wall hernias). These internal hernias can lead to heartburn, trouble swallowing and breathing difficulties.
Causes and risk factors
Two factors that increase the risk of hernias are weak abdominal muscles and weak connective tissue. Some people are born with weak connective tissue, whereas in others it becomes weaker in older age. Illnesses or surgery can also weaken tissue and muscles.
Being very overweight increases the pressure in your abdomen. But this doesn’t increase the risk of all the different types of hernias: While it increases the risk of incisional and umbilical hernias, it doesn’t affect the risk of inguinal hernias. Tumors or a build-up of fluid in the abdomen can increase the pressure on the abdominal wall too.
Pregnant women are more prone to abdominal wall hernias as well. Smoking and illnesses like diabetes can make it more difficult for wounds to heal properly after surgery, which makes incisional hernias more likely.
Lifting heavy objects, coughing and straining can make existing hernias grow in size. Whether these things can also cause hernias in the first place probably depends on the type of hernia. It isn’t clear whether this is the case with inguinal hernias, for example.
Inguinal hernias are the most common type of hernia: About 25 out of 100 men and 2 out of 100 women have at least one inguinal hernia at some point in their lives. The second most common types of hernia are umbilical and incisional hernias. Depending on the kind of surgery done, up to 15 out of 100 people develop incisional hernias following surgery that involves cutting their abdominal wall. Epigastric hernias, femoral hernias and diaphragmatic hernias are less common.
If left untreated, hernias can get bigger over time, become more visible and cause more problems, but these are rarely serious.
But sometimes the hernia sac becomes constricted and may, for instance, trap part of the intestine. This can cause the intestine to become blocked (obstruction), which leads to severe pain, nausea and vomiting. If the blood vessels are pinched too, the tissue in the hernia sac might die and result in peritonitis (inflammation of the peritoneum). In rare cases, the skin covering the hernia may thin out and die. If that happens, the area may become inflamed or the hernia might break through the skin.
Trapped hernias are always an emergency and must be operated on within a few hours. The risk of a hernia getting trapped is different for different types of hernias. For instance, it is more likely with femoral hernias than it is with inguinal hernias because the opening of the hernia is narrower.
Hernias are often clearly recognizable as such. The doctor first takes a look while the patient is standing, after asking them to tense their stomach muscles and cough. Then the patient is asked to lie down. This makes it easier for the doctor to feel how big the hernia sac is and see whether it can be pushed back into the abdomen. A stethoscope can be used to listen for bowel sounds in the hernia sac.
Whether and how hernias can be prevented depends on the type of hernia. To prevent incisional hernias, it’s a good idea to avoid strain due to things like carrying heavy objects following surgery at first. Losing weight can lower the risk of incisional hernias. But weight loss won’t help prevent inguinal hernias – and it isn’t clear whether carrying heavy objects plays a role in their development.
Stopping smoking can help surgical wounds heal better, which probably lowers the risk of incisional hernias. It is also important to make sure that medical conditions like diabetes and anemia are treated properly.
Surgery is the only treatment option for hernias. It involves pushing the hernia sac back into the abdomen or removing it, and closing the gap in the abdominal wall with stitches. A fine synthetic mesh is usually placed on the affected area too, to strengthen the abdominal wall and prevent the hernia from coming back.
In open surgery, the operation is carried out through a larger cut where the hernia is. In minimally invasive surgery (also called laparoscopic or keyhole surgery), several smaller cuts are made. The abdomen or abdominal wall are operated on by inserting surgical instruments and a fine tube with a camera attached to it (laparoscope) through the cuts. The camera enables the surgeon to see the inside of the abdomen on a monitor. The surgery options will depend on things like the type and size of the hernia.
Hernias don’t always have to be operated on. If they aren’t causing any problems and the risk of complications is low, surgery isn’t necessary. This is also true in people who are very old, weak or seriously ill and have a hernia that doesn’t pose an acute risk.
Hernia supports or hernia belts – tight, belt-like bandages – were often used in the past to try to stop hernias from bulging out of the abdomen. This is discouraged nowadays, though, because they don’t make the hernia go away and can have side effects such as pressure ulcers (bedsores).
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