Hydroceles and inguinal hernias are common in children. Hydroceles are typically asymptomatic and cause no damage to the testicle, whereas inguinal hernias can rarely result in bowel strangulation –a serious complication.
It is not always easy to distinguish an inguinal hernia from a hydrocele.
There are two types of hydroceles: communicating and non-communicating. Non-communicating hydroceles are collections of fluid in the scrotum sometimes extending into the groin that do not change in size appreciably from moment to moment, day to day, or even over weeks. Because the scrotum responds to temperature by shrinking when cold and loosening when hot, sometimes the scrotal change is misinterpreted as a change in the size of the hydrocele, but this is not a true change in the size of the hydrocele. On the other hand, communicating hydroceles are collections of fluid in the scrotum that do change in size — most commonly being small in the morning and large in the evening.
Communicating hydroceles and inguinal hernias are anatomically the same thing: there is an open window in between the abdomen and the scrotum (patent processus vaginalis) that allows fluid — in the case of a hydrocele — or intestines or bowel fat — in the case of an inguinal hernia — to travel from the abdomen into the groin/scrotum. The only anatomic difference in between a communicating hydrocele and a hernia is the size of the window: small for a communicating hydrocele and larger for a hernia, as shown here:
Clinically, with communicating hydroceles parents report a gradual change in the size of the scrotum throughout the day, with the scrotum being small in the morning and larger at the end of the day. The change is gradual so it is never “witnessed” directly.
On the other hand with hernias, parents “witness” the change in the size of the scrotum/groin when the child coughs, laughs or strains. The hernia then recedes back into the scrotum as the child relaxes or the parents can sometimes push the hernia back into the abdomen.
The diagnosis is usually made from the parent’s history and rarely only from the physical exam. Many times the hernias are not seen during the doctor’s appointment so history is key. It helps when the parents have taken some pictures of the swelling.
In children, I never try to feel a “hernia defect” with my finger during the physical exam as it is commonly done in adults: hernias in adults are due to muscle/fascia defects whereas in children they are due to a patent processus vaginalis.
Non-communicating hydroceles can be observed indefinitely as long as they are asymptomatic since there is no association with damage to the testis or any long term consequences. Non-communicating hydroceles are especially common in newborns, where they tend to disappear on their own in the first few months of life.
In older children, non-communicating hydroceles sometimes pop up out of nowhere. These also tend to be asymptomatic for the most part but can be disturbing for the parents to see.
Christensen et al found a 75% chance of resolution for non-communicating hydroceles of new onset in boys older than 1 year of age. They recommended an observation period of 6-12 months prior to repair. This is in contrast with the recommendation to operate on hydroceles that appear after the first 1-2 years of life made by the Canadian Association of Pediatric Surgeons.
Inguinal Hernias and communicating hydroceles
Hernias and communicating hydroceles have been traditionally repaired soon after diagnosis. Although the risks of incarceration (bowel/abdominal fat getting trapped in the scrotum) and strangulation (dead bowel in the scrotum) for a hernia have been clearly delineated in the literature (10% for incarceration and 1% for strangulation), little is known about the risks associated with observation of a communicating hydrocele beyond 2 years of age.
A 2003 survey of the American Academy of Pediatrics section of surgery found that “in cases of communicating hydrocele in the absence of any definite physical examination findings of hernia, 46% of respondents treat electively with hernia repair, compared with two thirds in the 1993 survey. Among 2003 respondents, 30% treat at 12 months of age, 7% at 6 months, 3% at 2 years, and 2% at 18 months”. Little has been reported about the natural history of hydroceles that are communicating by history or examination to support or discourage such early repair.
Koski et al observed 174 infant boys presenting with an apparent communicating hydrocele (before 18 months of age) without surgery, noting 63% complete resolution at a mean age of 11.7 months. Six (5%) developed a hernia during observation, none of which had an episode of incarceration. They concluded that little risk is taken by initially observing communicating hydroceles in infants with the potential of spontaneous resolution in the majority.
As noted above, the rate of spontaneous resolution of communicating and non-communicating hydroceles is similar at around 2/3. Although Christensen reported on the natural history of non-communicating hydroceles of new-onset in boys older than 1 year of age, there are no reports with regards to communicating hydroceles of new-onset if boys older than 1 year of age.
Hernias have been typically repaired soon after they are diagnosed, even in premature or sick newborns, due to the higher risk of incarceration/strangulation reported in the literature for premature babies. However, there has been a recent trend to postpone surgery until health has been optimized and the child can tolerate anesthesia better.
The history is key for diagnosing hydroceles and hernias.
Non-communicating hydroceles can be observed for a few months at any age since they are not associated with serious complications or damage to the testis, and they go away on their own 2/3 of the time.
Communicating hydroceles are also benign and have been shown to be safe to observe during the first couple of years of life but little has been reported on their natural history after the age of 2 years.
Inguinal hernias are typically repaired soon after the diagnosis is made when the health of the child is optimal.