Hernia (Abdominal Hernia)

Medical Author : Benjamin Wedro, MD, FACEP, FAAEM

Medical Editor : William C. Shiel Jr., MD, FACP, FACR

What is an abdominal hernia?

A hernia is the protrusion of an organ or piece of tissue from its normally contained space. In the abdomen, a hernia usually involves a piece of bowel, or omentum, which is a fatty apron that hangs down from the midportion of the colon (large intestine), protruding through a weak area in the abdominal wall. The abdominal wall is made up of layers of different muscles and tissues. Weak spots may develop in these layers to allow contents the abdominal cavity to protrude. The most common hernias are in the groin (inguinal hernias) and in the diaphragm (hiatal hernias). Hernias may be present at birth (congenital), or they may develop at any time thereafter (acquired).

What are the different types of abdominal hernias?

Hernias of the abdominal and pelvic floor

Inguinal hernias are the most common of the abdominal hernias. The inguinal canal is the opening that allows the spermatic cord and testicle to descend from within the abdomen where they develop in a fetus into the scrotum. After the testicle descends, the opening is supposed to close tightly but sometimes the muscles that attach to the pelvis leave a weak area. In women, therefore, inguinal hernias are less likely to occur because there is no need for a permanent opening in the inguinal canal.

A femoral hernia may occur through the opening in the floor of the abdomen where the femoral artery and vein pass through to the leg. Because of their wider bone structure, femoral hernias tend to occur more frequently in women.

Obturator hernias are the least common hernia of the pelvic floor. These are mostly found in women who have had multiple pregnancies or who have lost significant weight. The hernia occurs through the obturator canal, another connection of the abdominal cavity to the leg, and contains the obturator artery, vein, and nerve.

Hernias of the anterior abdominal wall

The abdominal wall is made up of muscles that mirror each other from right and left. These include the rectus abdominus as well as the internal obliques, the external obliques, and the transversalis. Diastasis recti is not a true hernia but rather a weakening of the membrane where the two rectus abdominus muscles from the right and left come together.

When epigastric hernias occur in infants, they occur because of a weakness in the midline of the abdominal wall where the two rectus muscles join together between the breastbone and belly button. Sometimes this weakness does not become evident until later in adult life as it becomes a bulge in the upper abdomen.

The belly button, or umbilicus, is where the umbilical cord attached the fetus to mother allowing blood circulation to the fetus. Umbilical hernias cause abnormal bulging in the belly button and are very common in newborns and often do not need treatment unless complications occur. Some umbilical hernias enlarge and may require repair.

Spigelian hernias occur on the outside edges of the rectus abdominus muscle and are rare. Incisional hernias occur as a complication of abdominal surgery, where the abdominal muscles are cut to allow the surgeon to enter the abdominal cavity to operate. Although the muscle is usually repaired, it becomes a relative area of weakness, potentially allowing abdominal organs to herniate through the incision.

Hernias of the diaphragm

Hiatal hernias occur when part of the stomach slides through the opening in the diaphragm where the esophagus passes from the chest into the abdomen. A sliding hiatal hernia is the most common type and occurs when the lower esophagus and portions of the stomach slide through the diaphragm into the chest. Paraesophageal hernias occur when only the stomach herniates into the chest alongside the esophagus. This can lead to serious complications of obstruction or the stomach twisting upon itself (volvulus).

Traumatic diaphragmatic hernias may occur due to major injury where blunt trauma weakens or tears the diaphragm muscle allowing immediate or delayed herniation of abdominal organs into the chest cavity. This may also occur after penetrating trauma from a stab or gunshot wound.

Congenital diaphragmatic hernias are rare and are caused by failure of the diaphragm to completely form and close during fetal development. This can lead to failure of the lungs to fully develop and decreased lung function if abdominal organs migrate into the chest. The most common type is a Bochdalek hernia at the side edge of the diaphragm. Morgagni hernias are rare and are a failure of the front of the diaphragm.

Picture of different types of hernias.
Picture of different types of hernias.

What causes an abdominal hernia?

A hernia may be congenital and present at birth or it may develop over time in areas of weakness within the abdominal wall. Increasing the pressure within the abdominal cavity can cause stress at the weak points and allow parts of the abdominal cavity to protrude or herniate.

Increased pressure within the abdomen may occur in a variety of situations including chronic cough, increased fluid within the abdominal cavity (ascites), peritoneal dialysis used to treat kidney failure, and tumors or masses in the abdomen. The pressure may increase due to lifting excess weight, straining to have a bowel movement or urinate, or from trauma to the abdomen. Pregnancy or excess abdominal weight and girth are also factors that can lead to a hernia.

What are the signs and symptoms of an abdominal hernia?

Most people can feel a bulge where an inguinal hernia develops in the groin. There may be a burning or sharp pain sensation in the area because of inflammation of the inguinal nerve or a full feeling in the groin with activity. If a hernia occurs because of an event like lifting a heavy weight, a sharp or tearing pain may be felt. However, many people do not have any complaint other than a feeling of fullness in the area of the inguinal canal.

Complications occur when a piece of intestine or omentum becomes trapped (incarcerated) in the hernia sac. A piece of bowel may enter the hernia and become stuck. If the bowel swells, it can cause a surgical emergency as it loses its blood supply and becomes strangulated. In this situation, there can be significant pain and nausea and vomiting, signaling the possible development of a bowel obstruction. Fever may be associated with strangulated, dead bowel.

A Richter's hernia causes only a part of the bowel wall to become trapped stuck in the hernia. It won't necessarily cause an obstruction since the passageway of the intestine still allows bowel contents to pass, but that portion of the bowel wall that is trapped can strangulate and die.

Femoral and obturator hernias present in much the same way as inguinal hernias, though because of their anatomic location, the fullness or lumps may be much more difficult to appreciate.

Umbilical hernias are easy to appreciate and in adults often pop out with any increase in abdominal pressure. The complications again include incarceration and strangulation.

A hiatal hernia does not cause many symptoms by itself, but when a sliding hernia occurs, the abnormal location of the gastroesophageal (GE) junction above the diaphragm affects its function and stomach contents can reflux into the esophagus. Gastroesophageal reflux (GERD) may cause burning chest pain, epigastric pain and burning in the upper abdomen nausea, vomiting, and a sour taste from stomach acid that washes into the back of the throat.

Sports hernias cause increased pain in the groin or inguinal area brought on by physical activity, usually involving twisting or blunt force trauma to the abdomen. 

How are abdominal hernias diagnosed?

For inguinal hernias, most patients notice a feeling of fullness or a lump in the groin area with pain and burning. Physical examination can usually confirm the diagnosis. Femoral or obturator hernias are more difficult to appreciate and symptoms of recurrent inguinal or pelvic pain without obvious physical findings may require a CT scan to reveal the diagnosis. Umbilical hernias are much easier to locate with the bulging of the belly button.

Hernias that are incarcerated or strangulated present a greater challenge since the potential complication of dead bowel increases the urgency. The health care professional seeks clues of obstruction including the presence of pain, nausea, vomiting, or fever. X-rays or CT scan may be required to assess the bowel but if the clinical diagnosis is made, emergency referral to a surgeon is usually required.

Hiatal hernias associated with GERD are often diagnosed by history and physical exam. The diagnosis may be confirmed by chest X-ray that can reveal part of the stomach within the chest. If there is concern about complications including esophageal inflammation (esophagitis), ulcers, or bleeding, an endoscopy by a gastroenterologist may be required.

What is the treatment for an abdominal hernia?

Inguinal hernia repair is one of the most common surgical procedures performed in the U.S. with almost a million operations occurring each year. Most abdominal wall hernias are repaired electively when the health of the patient can be maximized to decrease the risk of both the surgery and the anesthetic.

The inguinal hernia surgery may be performed by laparoscope or by an open procedure called a herniorrhaphy, where the surgeon directly repairs the hernia through an incision in the abdominal wall. The type of operation depends upon the clinical situation and the urgency of surgery and the decision is made by the surgeon tailored to that specific patient.

Other abdominal wall hernias can similarly be repaired to strengthen the defect in the abdominal wall and decrease the complication risk of bowel incarceration and strangulation.

Sliding hiatal hernias may be treated surgically to place the stomach back into the abdominal cavity and to strengthen the gastroesophageal junction. However, surgery is not routinely done because most symptoms are due to GERD. Medications, diet, lifestyle changes, and weight loss may help control symptoms and minimize the need for surgery.

Paraesophageal hernia repair is done to prevent the complication of strangulation or volvulus.

What non-surgical treatments are available for an abdominal hernia?

If an inguinal or umbilical hernia is small and does not cause symptoms, a watchful waiting approach may be reasonable. Routine follow-up may be all that is needed, especially if the hernia does not grow in size. However, if the hernia does grow or if there is concern about potential incarceration, then surgery may be recommended. Patients who are at high risk for surgery and anesthesia may be offered this approach.

Trusses, corsets, or binders can hold hernias in place by placing pressure on the skin and abdominal wall. These are temporary approaches and potentially can cause skin damage, breakdown, and infection because of rubbing and chaffing. They are often used in older or debilitated patients who have an increased risk to undergo surgery and when the hernia defect is very large.

Unless the defect is large, umbilical hernias in children tend to resolve on their own by 1 year of age. Surgery may be considered if the hernia is still present at age 3 or 4, or if the defect in the umbilicus is large.

Hiatal hernias by themselves do not cause symptoms. Instead it is the acid reflux that causes gastroesophageal reflux disease (GERD). Treatment is aimed at decreasing acid production in the stomach and preventing acid from entering the esophagus. For more, please refer to the Gastroesophageal Reflux Disease (GERD) article.

What is the prognosis for an abdominal hernia?

Most patients who undergo elective hernia repair do well. Incisional hernias may recur up to 10% of the time. The prognosis for patients who undergo emergent hernia repair because of incarcerated or strangulated bowel depends upon the extent of surgery, how much intestine is damaged, and their underlying health and physical condition prior to the surgery. For this reason, elective hernia repair is much preferred.

Can an abdominal hernia be prevented?

While congenital hernias cannot be prevented, the risk of developing a hernia that occurs as life goes on can be minimized. The goal is to decrease intra-abdominal pressure that can stress the weak areas in the abdominal wall.

  • Maintain a healthy weight.
  • Eat a healthy diet and exercise routinely to minimize the risk of constipation and straining to have a bowel movement.
  • Use proper lifting techniques especially when trying to lift heavy objects. This is important to remember at work, home, and in sports.
  • Stop smoking to decrease recurrent coughing.
  • If a hernia develops, seek medical care to have it evaluated and potentially treated before it gets too large or becomes incarcerated.

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