Hernia

A hernia occurs when an organ or tissue, like part of the bowel, pushes through a weak spot in the wall of the cavity that normally holds it. The word comes from Latin, meaning "rupture," though it also describes a normal stage in embryo development around 7½ weeks, when the intestine retracts into the abdomen from the navel area. Hernias most often affect the abdomen, especially the groin. Groin hernias are usually inguinal, but can also be femoral. Other common types include hiatus, incisional, and umbilical hernias.

About two-thirds of people with groin hernias have symptoms, such as pain or discomfort in the lower belly, especially when coughing, exercising, urinating, or defecating. The pain often worsens during the day and improves when lying down. A bulge may appear at the site and grow larger when bending over. Groin hernias are more common on the right side than the left. The main danger is bowel strangulation, where blood flow to part of the bowel gets cut off, causing severe pain and tenderness. Hiatus hernias often cause heartburn, but can also lead to chest pain or pain while eating.

Risk factors include smoking, chronic obstructive pulmonary disease, obesity, pregnancy, peritoneal dialysis, collagen vascular disease, and a past open appendectomy. Genetics play a role—hernias tend to run in families, with dominant inheritance patterns, especially in men. It is unclear whether heavy lifting contributes to groin hernias. Diagnosis is usually based on signs and symptoms, though medical imaging may be used to confirm or rule out other causes. Hiatus hernias are often diagnosed with endoscopy.

For men with groin hernias that cause no symptoms, immediate surgery is not needed—a "watchful waiting" approach is common. However, most men eventually have surgery due to developing pain. For women, repair is generally recommended because they have a higher rate of femoral hernias, which carry more complications. If strangulation occurs, surgery is urgent. Repair options include open surgery (which can sometimes be done under local anesthesia), laparoscopic surgery (which usually causes less post-op pain), or robotic-assisted surgery. For hiatus hernias, lifestyle changes like raising the head of the bed, losing weight, and adjusting eating habits may help. Medications such as H2 blockers or proton pump inhibitors can also be used. If symptoms persist, a surgery called laparoscopic Nissen fundoplication may be considered.

Globally in 2019, there were about 32.53 million prevalent cases of inguinal, femoral, and abdominal hernias, with 13.02 million new cases that year—a 36% increase in prevalence and a 64% increase in incidence since 1990. About 27% of males and 3% of females develop a groin hernia at some point. In 2015, these hernias affected 18.5 million people and caused 59,800 deaths. Groin hernias are most common before age 1 and after age 50. How common hiatus hernias are is unclear, with estimates in North America ranging from 10% to 80%. The earliest known description of a hernia dates to at least 1550 BC, found in the Ebers Papyrus from Egypt.

Most hernias develop when the muscles and tendons of the belly weaken or become damaged, making it harder to keep internal organs in place. The abdomen and pelvis form a container of muscles, tendons, and bones. When pressure builds inside, the muscles push back. If the pressure becomes too high, the belly wall can tear, creating a hernia. Once formed, the hernia tends to enlarge because tension on the wall increases. Symptoms and signs vary by type. The most common hernias occur in the abdomen when a weak spot becomes a hole, or "defect," through which fatty tissue or abdominal organs covered by peritoneum can protrude. Other common hernias involve spinal discs, causing sciatica. A hiatus hernia happens when the stomach pushes into the chest through the diaphragm's esophageal opening. Hernias may cause pain, a noticeable lump, or less specific symptoms from pressure on a trapped organ. Fatty tissue usually enters first, but an organ may follow. The bulge may come and go, but the tissue defect remains. Some inguinal hernias have no symptoms; reducible ones show a bulge in the groin or elsewhere.