WHAT IS a HERNIA?
A hernia occurs when there is a weakness in the layers of the abdominal wall.
The pressure from inside the abdomen then pushes the lining of the abdominal wall, the peritoneum, out through this area of weakness, leading to a bulge under the skin. The hernia sac may start as a small lump, which disappears when the patient is lying down, and may be only apparent when standing or straining (coughing). Hernias are not always painful, they can be found incidentally. Over time hernias typically increase in size and can become quite large due to pressure from the abdomen pushing intra-abdominal fat and intestines (bowel) out, which can get stuck in the hernia sac (incarcerated) and potentially strangulate. For this reasons most hernias require surgical repair to alleviate symptoms and to prevent possible complications.
Causes of hernia
In many cases a hernia presents as a painless lump that needs no immediate medical attention.
It is usually more obvious when standing, straining, or lifting heavy objects. A hernia may, however, be the cause of discomfort and pain depending upon its size and contents.
- Abdominal straining (heavy lifting, constipation, urinary retention)
- Persistent cough
- Poor nutrition
- Ascites (accumulation of abdominal fluid)
- Undescended testes
- Peritoneal dialysis
- Physical exertion
Signs & Symptoms of hernia
In most cases, there is no obvious reason for a hernia to occur.
The wall of the abdomen has natural areas of potential weakness. Hernias can develop at these or other areas due to heavy strain on the abdominal wall. Anyone can get a hernia at any age, although hernias occur more commonly in men and increase with age. Most hernias in children are congenital whilst in adults they are acquired. Factors that are associated with an increased risk of developing a hernia include:
Immediate surgical attention should be sought if a hernia is associated with;
- Obstipation (absence of flatus or bowel motions)
In this instance the hernia may need emergent surgery. The hernia in this situation is typically firm and tender and cannot be pushed back into the abdomen (irreducible).
Diagnosis of hernia
The diagnosis of hernia is usually made by clinical examination – the doctor will usually be able to see and/or feel a lump.
The cardinal feature is the presence of a palpable cough impulse.
The doctor may arrange an imaging test, such as an ultrasound or a CT (computerized tomography) scan to help define the anatomy.
How will my hernia be treated?
The treatment depends on the type of hernia.
There are many types of hernias and they can appear in different parts of the body. The most common types are;
- Inguinal hernia
- Femoral hernia
- Umbilical hernia
- Ventral hernia
- Incisional hernia
- Giant abdominal hernia
- Recurrent hernia
- Parastomal hernia
Types of hernia
There are many types of hernias and most are classified by their anatomical location.
Approximately 75% of all abdominal wall hernias are seen in the groin of which inguinal hernia is most common.
An inguinal hernia is a groin hernia that results from protrusion of abdominal contents through the inguinal canal. There are two types of inguinal hernia;
- Direct inguinal hernia occur medial to the inferior epigastric vessels when abdominal contents protrude through a weakness in the posterior wall of the inguinal canal, which is formed by the transversalis fascia. This type of hernia usually occurs following heavy lifting.
- Indirect inguinal hernia occur when abdominal contents protrude through the deep inguinal ring, lateral to the inferior epigastric vessels. This is usually caused by failed closure of embryonic processus vaginalis.
Inguinal hernias usually present as a lump in the groin. They can become more prominent when coughing, straining or standing. The lump usually disappears when lying down. Inguinal hernia are usually asymptomatic, and only rarely painful. Although most are unilateral, up to 20% of patients go on to develop one on the contralateral side.
Femoral hernias are a rare type of groin hernia. In contrast to inguinal hernia almost all femoral hernia occur in females due to the female pelvis being wider. In a femoral hernia the abdominal contents protrude medial to the nerves and vessels that supply the leg, through the femoral canal. Due to the femoral canal being narrow, femoral hernia are at increased risk of incarceration and strangulation of abdominal contents.
Umbilical & Paraumbilical hernia
An umbilical hernia is a type of ventral hernia, which is located in the central aspect of the umbilicus. They are also commonly referred to as “bellybutton” or “navel” hernias. They may be present from birth and in 85% of cases will close spontaneously. If the hernia persists beyond five years of age, they are less likely to improve and may require surgery. It is uncommon for umbilical hernias in children to strangulate. It is therefore reasonable to avoid surgery and adopt a wait-and-see policy.
In adults, hernias that occur around the umbilicus are termed “paraumbilical” hernias. The umbilicus is a natural weak point in the abdominal wall. They typically present as a “bulge” or “outie” in the bellybutton. Apart from in pregnancy, they don’t disappear, and surgery is usually recommended. The diagnosis is usually made clinically. Ultrasound or CT may be helpful but are usually not necessary.
A ventral hernia results from a defect in the midline of the abdominal wall. They are also referred to as “epigastric” hernia. Most present with a small lump, that is usually asymptomatic, anywhere in the midline between the xiphoid process (lower end of sternum) and the umbilicus. They rarely cause complications. In some instances, imaging by Ultrasound or CT is required to confirm the diagnosis and help plan treatment.
Incisional hernia is a type of hernia that develops due to incomplete healing of an abdominal wound. They therefore present as a lump at or near the surgical scar. Factors associated with an increased risk of incisional hernia include, multiple abdominal operations, obesity, poor nutrition or activities in the post-operative period associated with increased abdominal pressure (coughing, lifting, constipation, urinary retention). Surgery repair is commonly advised but not always required. Imaging by Ultrasound or CT may be required to confirm the diagnosis and extent of herniation, to help ascertain whether surgery is required.
Giant abdominal hernia
A giant abdominal wall hernia can develop from any long-standing hernia or as a result of delayed closure of the abdominal wall. They usually have a history of multiple failed repair attempts. The large defect allows for multiple loops of intestines and on occasion, other abdominal organs, to protrude into the hernia sac. Giant abdominal hernia are difficult to repair and often require a combination of mesh repair and/or component separation to bridge the large defect in the abdominal wall.
A parastomal hernia is a type of incisional hernia where there is protrusion of intra-abdominal contents though the abdominal wall defect created during stoma formation. Examples include ileostomy (terminal small bowel brought to the skin), colostomy (colon brought to the skin) gastrostomy (stomach or feeding tube brought to the skin) or urostomy (urinary diversion brought to the skin). Parastomal hernias are often difficult to diagnose and develop gradually over time. They often make it difficult to attach an appliance over the stoma and over time can increase dramatically in size. Treatment often requires more than one specialist and may involve either the re-siting of the stoma or repair of the hernia around the stoma with the use of mesh.
A spigelian hernia or lateral ventral hernia is a hernia that extends through the linea semilunaris, the line between the lateral edge of the rectus muscle and the oblique muscles of the abdominal wall. They almost always develop in the lower abdominal wall, more commonly on the right. They usually present with a lump and due to their small size, are at high risk of strangulation. Imaging by Ultrasound or CT is usually necessary to establish the diagnosis.
A recurrent hernia is the recurrence of a hernia following surgical repair. It usually presents as a lump at or near the site of previous repair. It needs to be differentiated from other causes, such as seroma (fluid collection) or hematoma, and imaging is sometimes helpful. A recurrent hernia usually requires further surgical repair. Unfortunately the success rate of the subsequent repair is less and it is associated with increased rate of complications.
A sportsman hernia is a chronic exercise-related groin pain associated with incipient direct bulge of the inguinal wall whenever the abdominal muscles contract forcefully. The pain develops during exercise, is usually unilateral and is located just above the inguinal ligament at the lateral aspect of rectus abdominus. The majority of the patients are young adult males. There is often no objective physical examination findings. A cough impulse is either weak or absent. Imaging by Ultrasound, CT or MRI may be helpful in showing a direct bulge of the posterior inguinal wall when forcefully contracting the abdominal muscles.
Most hernias are reducible which means that the contents can be reduced back into the abdominal cavity.
Some hernias are irreducible, also called “incarcerated” and cannot be reduced back into the abdomen. This can lead to the following complications:
- Strangulation – Pressure at the hernia neck on the contents may compromise the blood supply to the part of intestine or organ that has herniated leading to aschemia and gangrene. A strangulated hernia is life-threatening and requires immediate surgery to reduce and repair the hernia.
- Obstruction – When part of the intestine herniates, the bowel contents may no longer be able to pass through the herniated area leading to bowel obstruction. This usually presents with crampy abdominal pain, absence of defecation and vomiting. This is an emergency that requires immediate surgical repair.
Anyone with a hernia who develops any of the following symptoms should seek urgent medical attention:
- sudden and severe pain
- nausea and vomiting
- obstipation (absence of defecation and flatus)
- hernia is tender and will not reduce