An inguinal hernia in an infant or child is due to a persistent communication with the abdominal cavity. Inguinal (groin) hernias are the most common type of hernia in children. They occur in up to 5% of children. Factors associated with an increased risk of hernia include prematurity (less than 36 weeks gestation), and male gender (4-8 fold increase). Some underlying medical conditions (cystic fibrosis, hydrocephalus, peritoneal dialysis patients) also have an increased risk of an inguinal hernia.
What causes an inguinal hernia?
An inguinal hernia is an opening between the abdominal cavity and the inguinal canal which should have closed prior to birth, but has persisted. The communication may only allow fluid to pass through, resulting in a fluid collection in the scrotum (hydrocele). A larger opening may allow the bowel and, occasionally the ovary in females, to protrude down into the inguinal canal.
Causes of inguinal hernias: Children are born with an indirect inguinal hernia. Although adults can have hernias in the same location, they are usually acquired (muscle weakness or tear), and are known as direct inguinal hernias.
What are the signs and symptoms of inguinal hernia?
Most hernias are identified as a result of the parent or child noticing bulging or swelling in the groin or scrotum in boys. Anything that increases the pressure in the abdomen (when a child cries, coughs or stands) can cause the bulging to become visible. The coughing or straining does not cause the hernia, but may lead to the bulging, resulting in the identification of the hernia. The swelling may disappear when lying down.
Pain is an infrequent symptom of an inguinal hernia in children. In infants, the child may be irritable and fussy, and the question often arises as to whether the hernia is causing the symptoms, and if the fussiness will resolve if the hernia is repaired. The usual answer is that the hernia should be repaired, regardless. Sometimes the symptoms will resolve, but in other cases another cause such as colic, hunger, or a multitude of other possibilities are responsible for the irritability, increased abdominal pressure, and observation of the hernia (chicken versus egg – which comes first?), and repair of the hernia will not relieve the symptoms.
In older children, pain in the inguinal region, in the absence of observed bulging or swelling, can sometimes be due to a hernia. However, musculoskeletal strains and other etiologies are often responsible as well.
Imaging studies (plain films, ultrasound, CT scans) are not generally useful in the evaluation of a possible inguinal hernia. The diagnosis is usually made by history and physical examination. Sometimes, the history is unclear, and the physical exam at the clinic or office visit may be normal. The physician and parents may decide to observe the child or proceed to operative repair, based on the individual circumstances. With widespread availability of cell phones, parents sometimes take pictures of the bulging to help with the diagnosis. These can be uploaded directly to the patient portal for the surgeons and nurse practitioners to review.
Inguinal hernia complications
The reasons to repair an inguinal hernia include:
They will not resolve without operation
They can cause symptoms (fullness, pain)
There is a risk of incarceration (bowel or ovary trapped in the hernia opening and unable to be reduced) or even strangulation (trapped bowel or ovary which becomes edematous and swollen, and the blood supply is cut-off or compromised, with death of the trapped intestine or ovary).
The chance of incarceration or strangulation is highest in the youngest infants, but it is not a frequent occurrence. Signs include abdominal distention, vomiting, irritability and fussiness/pain, and a painful / tender swelling in the groin which cannot be reduced.