Pediatric Hernias Clinical Presentation

• The infant or child with an inguinal hernia generally presents with an obvious bulge at the internal or external ring or within the scrotum. The parents typically provide the history of a visible swelling or bulge, commonly intermittent, in the inguinoscrotal region in boys and inguinolabial region in girls. The image below depicts a 4-month-old baby boy with a large right-sided inguinal hernia. Typical appearance of an infant with a large right indirect inguinal hernia. The right scrotal sac is enlarged and contains palpable loops of bowel and fluid.
• The swelling may or may not be associated with any pain or discomfort. More commonly, no pain is associated with a simple inguinal hernia in an infant. The parents may perceive the bulge as being painful when, in truth, it causes no discomfort to the patient.
• The bulge commonly occurs after crying or straining and often resolves during the night while the baby is sleeping.
• Indirect hernias are more common on the right side because of delayed descent of the right testicle. Hernias are present on the right side in 60% of patients, on the left in 30%, and bilaterally in 10% of patients.
• If the patient or the family provides a history of a painful bulge in the inguinal region, one must suspect the presence of an incarcerated inguinal hernia. Patients with an incarcerated hernia generally present with a tender firm mass in the inguinal canal or scrotum. The child may be fussy, unwilling to feed, and inconsolably crying. The skin overlying the bulge may be edematous, erythematous, and discolored.

Examine the patient in both supine and standing positions. Physical examination of a child with an inguinal hernia typically reveals a palpable smooth mass originating from the external ring lateral to the pubic tubercle. The mass may only be noticeable after coughing or performing a Valsalva maneuver, and it should be reduced easily. Occasionally, the examining physician may feel the loops of intestine within the hernia sac. In girls, feeling the ovary in the hernia sac is not unusual; it is not infrequently confused with a lymph node in the groin region. In boys, palpation of both testicles is important to rule out an undescended or retractile testicle.

• Inguinal hernia incarceration: The bowel can become swollen, edematous, engorged, and trapped outside of the abdominal cavity, a process known as incarceration. Incarceration is the most common cause of bowel obstruction in infants and children and the second most common cause of intestinal obstruction in North America (second only to intra-abdominal adhesions from previous surgeries). If entrapment becomes so severe that the vascular supply is compromised, inguinal hernia strangulation results. In cases of incarceration, ischemic necrosis develops, and intestinal perforation may result, representing a true medical emergency. When an incarceration is encountered, an attempt should be made to reduce it manually if the patient has no signs of systemic toxicity (eg, leukocytosis, severe tachycardia, abdominal distention, bilious vomiting, discoloration of the entrapped viscera). If the patient appears toxic, emergent surgical exploration after appropriate resuscitation is necessary.
• Hernia and hydrocele: In boys, differentiating between a hernia and a hydrocele is not always easy. Transillumination has been advocated as a means of distinguishing between the presence of a sac filled with fluid in the scrotum (hydrocele) and the presence of bowel in the scrotal sac. However, in cases of inguinal hernia incarceration, transillumination may not be beneficial because any viscera that is distended and fluid-filled in the scrotum of a young infant may also transilluminate. A rectal examination may be helpful if intestine can be felt descending through the internal ring.
• Silk sign: When the hernia sac is palpated over the cord structures, the sensation may be similar to that of rubbing 2 layers of silk together. This finding is known as the silk sign and is highly suggestive of an inguinal hernia. The silk sign is particularly important in young children and infants, in whom palpation of the external inguinal ring and inguinal canal is difficult because the patients' small size.
• Spontaneously reducing hernia: Inguinal hernias that spontaneously reduce (ie, they are only noticed by the parents or caregivers and elude the examining physician) are not unusual. In such cases, maneuvers to increase the patient's intra-abdominal pressure may be attempted. Lifting the infant's or the child's arms above the head may provoke crying or a struggle to get free and thus increased intra-abdominal pressure. Older children can be asked to cough or blow up a balloon.
• Femoral hernia: A femoral hernia can be very difficult to differentiate from an indirect inguinal hernia. Its location is below the inguinal canal, through the femoral canal. The differentiation is often made only at the time of operative repair, once the anatomy and relationship to the inguinal ligament is clearly visualized. The signs and symptoms for femoral hernias are essentially the same as those described for indirect inguinal hernias.

The cause of inguinal hernia in children can be termed an abnormality of embryologic development of the fetus. However, some children may present with an acquired form of inguinal hernia, also called a direct inguinal hernia. In this type of hernia, weakness of the inguinal floor is present, which allows for protrusion of viscera from the abdominal cavity. The hernia sac is composed of the peritoneal fold that contains the hernia.

Anatomically speaking, indirect and direct inguinal hernias differ in that the direct hernia bulges through the inguinal floor medial to the inferior epigastric vessels and the indirect hernia arises lateral to the inferior epigastric vessels. Either hernia may cause fullness or a palpable bulge in the inguinal region, and distinguishing between the two types on the basis of physical examination findings may be difficult. The clinician may assume, until proven otherwise, that the pediatric patient with an inguinal hernia has indirect inguinal hernia.

• The following are associated with an increased risk of inguinal hernia:

  • Prematurity and low birth weight (Incidence approaches 50%.)
  • Urologic conditions
    • Cryptorchidism
    • Hypospadias
    • Epispadias
    • Exstrophy of the bladder
    • Ambiguous genitalia
  • Patent processus vaginalis, which may be present because of increased abdominal pressure due to ventriculoperitoneal shunts, peritoneal dialysis, or ascites
  • Abdominal wall defects
    • Gastroschisis
    • Omphalocele
  • Family history
    • Meconium peritonitis
    • Cystic fibrosis
    • Connective tissue disease
    • Mucopolysaccharidosis
    • Congenital dislocation of the hip
    • Ehlers-Danlos syndrome
    • Marfan syndrome
    • Cloacal exstrophy
    • Fetal hydrops
    • Liver disease with ascites
    • Ventriculoperitoneal shunting for hydrocephalus
• Figures regarding inguinal hernia incarceration indicate the following risk patterns:

  • Incarceration occurs in 17% of right-sided hernias and 7% of left-sided hernias.
  • More than 50% of cases of incarceration occur within the first 6 months of life; the risk gradually decreases after age 1 year.
  • Premature infants have twice the risk of incarceration than the general pediatric population.
  • More than two thirds of all incarcerations occur in children younger than 1 year.
  • Girls are more likely to develop incarceration of an inguinal hernia; the incidence in girls is 17.2%, whereas the incidence in boys is 12%.