A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Hernias come in a number of types. Most commonly they involve the abdomen, specifically the groin. Groin hernias are most commonly of the inguinal type but may also be femoral. Other hernias include hiatus, incisional, and umbilical hernias. Symptoms are present in about 66% of people with groin hernias. This may include pain or discomfort, especially with coughing, exercise or going to the bathroom. Often, it gets worse throughout the day and improves when lying down. A bulging area may appear that becomes larger when bearing down. Groin hernias occur more often on the right than left side. The main concern is strangulation, where the blood supply to part of the bowel is blocked. This usually produces severe pain and tenderness in the area. Hiatus, or hiatal, hernias often result in heartburn but may also cause chest pain or pain with eating.Risk factors for the development of a hernia include: smoking, chronic obstructive pulmonary disease, obesity, pregnancy, peritoneal dialysis, collagen vascular disease and previous open appendectomy, among others. Predisposition to hernias is genetic and occur more often in certain families. Deleterious mutations causing predisposition to hernias seem to have dominant inheritance (especially for men). It is unclear if groin hernias are associated with heavy lifting. Hernias can often be diagnosed based on signs and symptoms. Occasionally, medical imaging is used to confirm the diagnosis or rule out other possible causes. The diagnosis of hiatus hernias is often by endoscopy.Groin hernias that do not cause symptoms in males do not need to be repaired. Repair, however, is generally recommended in women due to the higher rate of femoral hernias, which have more complications. If strangulation occurs, immediate surgery is required. Repair may be done by open surgery or laparoscopic surgery. Open surgery has the benefit of possibly being done under local anesthesia rather than general anesthesia. Laparoscopic surgery generally has less pain following the procedure. A hiatus hernia may be treated with lifestyle changes such as raising the head of the bed, weight loss and adjusting eating habits. The medications H2 blockers or proton pump inhibitors may help. If the symptoms do not improve with medications, a surgery known as laparoscopic Nissen fundoplication may be an option.About 27% of males and 3% of females develop a groin hernia at some point in their lives. Inguinal, femoral and abdominal hernias were present in 18.5 million people and resulted in 59,800 deaths in 2015. Groin hernias occur most often before the age of 1 and after the age of 50. It is not known how commonly hiatus hernias occur, with estimates in North America varying from 10% to 80%. The first known description of a hernia dates back to at least 1550 BC, in the Ebers Papyrus from Egypt.