Practice Essentials
A hydrocele is a collection of fluid within the processus vaginalis (PV) that produces swelling in the inguinal region or scrotum. An inguinal hernia occurs when abdominal organs protrude into the inguinal canal or scrotum. Inguinal hernia and hydrocele share a similar etiology and pathophysiology and may coexist.
In the healthy male neonate, the testicle is surrounded by a closed cavity—the tunica vaginalis (TV) of the scrotum. In postnatal life, this is a potential space that should not communicate with the peritoneal cavity of the abdomen.
A bulge in the groin or scrotal enlargement is the classic presentation of hernia or communicating hydrocele. Pain is generally not a prominent feature but may occur if a hydrocele expands quickly; tension in the wall may cause milder pain. Severe pain raises concern about a strangulated hernia. Very rarely, a hydrocele may become infected and cause pain.
No medical therapy is effective for a hernia or a communicating hydrocele. Aspiration and injection of sclerosing agents have been recommended for noncommunicating hydroceles in adults, but this therapy is relatively contraindicated in children.
Surgical repair is generally accepted as the appropriate treatment for an inguinal hernia in children and adults. (See Treatment.) Unlike hernias in infants, many hydroceles in newborns resolve because of spontaneous closure of the patent PV (PPV) early after birth; accordingly, observation is often appropriate for hydroceles in infants. The following are indications for hydrocele repair:
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Failure to resolve by age 2 years
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Continued discomfort
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Enlargement or waxing and waning in volume
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Unsightly appearance
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Secondary infection (very rare)
Pathophysiology
During fetal development, the testicle is located below the kidney, within the peritoneal cavity. As the testicle descends through the inguinal canal and into the scrotum, it is accompanied by a saclike extension of peritoneum, otherwise known as the PV. After the testicle descends, the PV obliterates in the healthy infant and becomes a fibrous cord with no lumen. The distal tip of the PV remains as a membrane around the testicle (ie, the TV).
Normally, the inguinal region and scrotum should not connect with the abdomen. Neither abdominal organs nor peritoneal fluid should be able to pass into the scrotum or inguinal canal. If the PV does not close but remains patent, it is referred to as a PPV. If the PPV is small in caliber and only large enough to allow fluid to pass, the condition is referred to as a communicating hydrocele. If the PPV is larger, allowing ovary, intestine, omentum, or other abdominal contents to protrude, the condition is referred to as a hernia.
Multiple theories exist regarding the failure of PV closure. Smooth muscle has been identified in PPV tissue but not in normal peritoneum. The amount of smooth muscle present may correlate with the degree of patency. For example, higher amounts of smooth muscle have been found in hernia sacs than in the PPV of hydroceles. Investigation continues to determine the role of smooth muscle in the pathogenesis of this condition.
Etiology
Most hernias and hydroceles in children are due to idiopathic failure of the PV to close. Any condition that increases intra-abdominal pressure can delay or inhibit this closure.
The following conditions are associated with a higher incidence of hernia or hydrocele:
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Epispadias and exstrophy of the bladder
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Liver disease with ascites
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Abdominal wall defects
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Continuous ambulatory peritoneal dialysis
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Low birth weight
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Family history of hernia or hydrocele
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Hydrops
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Meconium peritonitis
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Connective tissue disease
Reactive hydroceles result from inflammation and fluid accumulation in the TV around the testicle, even though the PV is closed. A reactive hydrocele can result from the following factors:
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Trauma
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Torsion
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Infection (eg, epididymo-orchitis)
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Abdominal or retroperitoneal operations that impair lymphatic drainage
Epidemiology
United States statistics
The incidence of hernias is 10-20 per 1000 live births and is much higher after premature birth. Whereas hernias are more commonly located on the right side, as many as 10% are bilateral.
Age- and sex-related demographics
The incidence of PPV decreases with age. In newborns, 80-94% have a PPV. Hernias are 20 times more common in premature infants who weigh less than 1500 g than in babies born at term. As many as 30% of adults are discovered to have a PPV at autopsy. Why all PPVs do not develop into a hernia or hydrocele is not understood.
Hernias are six times more common in boys than in girls. Bowel incarceration is more common in females than in males. In females, an ovary or fallopian tube incarcerates more frequently than the bowel does. Therefore, the overall incidence of bowel strangulation is lower in females than in males.
Prognosis
The greatest risk associated with a hernia involves an intra-abdominal organ becoming trapped within the hernia sac. This condition is referred to as incarceration of the organ. If bowel becomes incarcerated, it may become edematous. The increased pressure may impair venous drainage, leading to more edema, which may impair arterial inflow of the bowel. This can ultimately cause bowel ischemia and possible rupture.
In a male, pressure placed on the spermatic cord by an incarcerated hernia may affect blood flow to the testis. When bowel perfusion is affected, a strangulated hernia exists. This condition can lead to perforation of the entrapped bowel, peritonitis, sepsis, and even death. Incarcerated or strangulated hernia is therefore a surgical emergency. If a strangulated bowel is reduced surgically at an early stage, viability may be preserved and bowel resection avoided. In children with a painful nonreducible hernia, incarceration should be suspected, necessitating emergency evaluation.
The omentum may become entrapped in a hernia, causing chronic abdominal pain with a persistent inguinal mass.
In females, the ovary or fallopian tube can enter hernia sacs and become incarcerated or strangulated. An incarcerated ovary is an urgent problem that may result in inguinal pain and infarction of the ovary. An incarcerated ovary does not carry the same risk of sepsis as is seen with bowel incarceration and perforation.
With open surgery, ipsilateral recurrence rates are lower than 1%. The ipsilateral recurrence rate after laparoscopic inguinal hernia repair is 3.4%. Recurrences are usually associated with comorbid conditions. The incidence of a metachronous contralateral hernia is inversely related to age and can be as high as 12%.
