Hernias are among the most frequent indications for elective surgery in children. In many institutions, patients are admitted onto the hospitalist service (with a surgical consultation). As such, the pediatric hospitalist must be aware of the relevant anatomy, presentation, and treatment options of this common condition.

Hernia refers to any opening, congenital or acquired, in the abdominal musculature or fascia that allows all or part of an abdominal viscus to protrude beyond its usual boundaries; the term is also sometimes used to refer to the protruding viscus itself. Most hernias include an extension of the peritoneum, the hernia sac, which encases the herniated viscus and must be excised as part of the surgical repair. An incarcerated hernia is one in which the herniated viscus cannot be reduced manually, usually because of edema. Strangulated hernia refers to an incarcerated hernia in which the vascular integrity of the herniated viscus is compromised. This usually involves venous and lymphatic congestion of the tissue but can progress to arterial insufficiency, ischemia, and eventually necrosis. Most incarcerated hernias constitute a surgical emergency. Sliding hernia refers to a hernia in which the serosa of an intra-abdominal organ forms part of the hernia sac, which can make for a more difficult repair.

The most common hernias in children are indirect inguinal and umbilical hernias. Essentially, all hernias in children are congenital defects and not the result of excessive straining or fascial disruption, which are often cited as causal factors in adults. Consequently, pain is rarely a symptom of an uncomplicated hernia in children. This also means that pediatric hernias rarely require fascial reconstruction or the use of prosthetic mesh, making the operation more straightforward and less painful than in adults.

Almost all hernias require operative repair, regardless of location or type. The only exception is an asymptomatic umbilical hernia in a child younger than 4 or 5 years, which will often resolve spontaneously.¹ No other type of true hernia is known to resolve spontaneously and all have a small but definite risk of incarceration and subsequent ischemia of the herniated viscus.² Reducible hernias do not require emergent repair and can usually be fixed electively, depending on the needs and preferences of the family.

Most elective hernias are repaired on an outpatient basis. Admission is indicated for young infants at risk for apnea (preterm babies less than 60 weeks corrected gestational age), some children with complex medical conditions, and those who require emergent operation for an incarcerated or otherwise complicated hernia.

The majority of inguinal hernias seen in children are indirect inguinal hernias. Indirect inguinal hernias result from persistence of the processus vaginalis, the remnant of an embryonic structure that plays a role in testicular descent and normally disappears before birth (Figure 156-1).

CLINICAL PRESENTATION

Most pediatric inguinal hernias present as an asymptomatic mass in the inguinal region, lateral to the rectus sheath and superior to the pubic tubercle. In some cases, it may appear as an asymmetry in the suprapubic fat pad; alternatively, because indirect inguinal hernias can extend into the scrotum, there may be a difference in the size of the scrotal contents. Hernias typically appear or become larger when the patient increases intra-abdominal pressure, such as during the Valsalva maneuver. The classic history is that of a painless groin bulge that appears during straining or crying; there are typically no other symptoms.

Although some children describe a vague discomfort when the inguinal hernia is “out,” the vast majority of uncomplicated hernias in children are painless. Moreover, pain alone is almost never an indication of the presence or imminent development of a hernia. The combination of an apparent hernia and severe pain should raise the suspicion that the herniated viscus has become incarcerated. Young infants with hernias pose a particular challenge because crying for any reason causes the hernia to become larger and more tense, raising the suspicion for incarceration. Parents should be instructed to console the child in the usual way (gentle rocking, changing the diaper, feeding). If the tense protrusion or hernia persists despite these measures after 20 to 30 minutes or if other symptoms such as vomiting or fever develop, the infant should be brought urgently to the emergency department. An experienced healthcare provider should attempt to reduce the hernia if it is in fact incarcerated.

An incarcerated inguinal hernia, which occurs in 10% to 12% of pediatric patients presenting with a hernia, is a true emergency.³ The presentation is rarely subtle. Children are typically in severe pain and very restless, unable to find a comfortable position. Frequently there is vomiting, as a reflex secondary to visceral compromise or due to bowel obstruction. Fever, dehydration, and lethargy are usually late signs that suggest bowel ischemia. The hernia itself is usually quite prominent, with or without overlying erythema; it is very tense and tender on examination. Bluish discoloration is not characteristic of a hernia but actually more often associated with hydrocele.

DIFFERENTIAL DIAGNOSIS

A history of an asymptomatic bulge in the groin that enlarges with straining and promptly resolves spontaneously or with gentle manual pressure is diagnostic of an inguinal hernia. It is sometimes difficult to distinguish an incarcerated hernia from other, usually more benign, processes (Table 156-1; Figure 156-2). These processes are varied and can include congenital, inflammatory/infectious, or rarely malignant etiologies.

DIAGNOSTIC EVALUATION

There is no imaging modality that can reliably confirm or rule out the presence of a hernia. The diagnosis is based solely on the history and physical examination. Ultrasonography is occasionally a useful adjunct to resolve clinical uncertainty, but when the diagnosis is uncertain or imaging studies are equivocal, pediatric surgical consultation should be sought.

On physical examination, an inguinal hernia is diagnosed by the presence of a bulge over the inguinal canal or in the scrotum that can be manually reduced into the abdomen. In a child, a subtle impulse appreciated when the patient coughs or strains is not sufficient evidence of a hernia. However, it is sometimes extremely difficult to make a hernia appear on request. Infants often strain upon palpation of the abdomen or cry when the diaper is removed. Older children are examined while standing and asked to bear down. They have often learned techniques to make the hernia come out which can be facilitated by having them jump up and down or asking them to inflate a non-latex examination glove like a balloon.

MANAGEMENT

Inguinal hernias never resolve spontaneously. They have a tendency to enlarge and sometimes become more symptomatic over time. There is a small but definite risk of incarceration that is impossible to quantify based on size or clinical criteria. Therefore all inguinal hernias should be surgically repaired.

Once the diagnosis is confirmed, operative intervention is recommended within 2 to 3 months. An incarcerated hernia that cannot be reduced requires immediate operation. In addition to the complications associated with emergency surgery and the potential for bowel ischemia, an episode of incarcerated hernia can increase the risk of testicular ischemia or atrophy. In girls with incarcerated hernia of the ovary, torsion or injury to the exposed ovary is also possible.

Because the risk of incarceration is so difficult to predict, guidelines regarding restriction of activities for patients awaiting surgery are difficult to formulate. Mild physical activities do not appear to increase the risk of incarceration for patients with asymptomatic and uncomplicated inguinal hernias. Extreme physical exertion that involves a great deal of straining or the potential for direct injury to the hernia contents should probably be restricted until after surgery. In practice, restrictions are generally based on common sense and the perceived risk of liability for the individual or group (school officials, athletic directors, employers) making the recommendation.