Inguinal Hernia and Hydrocele
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Direct answer
Inguinal hernia and hydrocele in children both arise from a patent processus vaginalis. A hernia contains bowel or ovary, does not resolve and needs high ligation of the sac. A hydrocele contains only fluid and often resolves within one to two years. Prompt repair of a hernia is advised, because incarceration can occur at any age and is most dangerous in infants.
What you must remember
- Common cause: a patent processus vaginalis, the peritoneal sac that should obliterate by term or soon after birth.
- Hernia contents: bowel in most boys and frequently the ovary in girls, which makes ovarian incarceration a classic exam point.
- Incarceration risk: higher in infants, particularly premature infants, and it presents as an irreducible, tender groin swelling.
- Hydrocele: fluid-filled and transilluminant, often resolving in the first year or two, with persistence beyond this prompting repair.
- Side and sex: inguinal hernia is more common in boys and on the right side, and the opposite side is often patent.
- Repair: high ligation of the sac at the internal inguinal ring, usually as a day-case procedure.
- Care during surgery: the vas deferens and testicular vessels run in the cord and must be protected.
Telling a hernia from a hydrocele at the bedside
Most exam questions turn on a few bedside differences, and the table covers them. The two conditions share a cause, but they differ in contents, behaviour and urgency.
| Feature | Inguinal hernia | Hydrocele |
|---|---|---|
| Contents | Bowel in most boys, ovary often in girls | Fluid only, with no bowel or ovary |
| Transillumination | Usually negative, though a thin-walled infant hernia may transilluminate | Positive, with a translucent swelling |
| Cough impulse | Usually present | Usually absent |
| Swelling pattern | Varies with crying or straining, may be irreducible | Constant scrotal swelling |
| Commonest age | Infancy, with premature infants at higher risk | Newborn and infancy |
| Natural history | Does not resolve and can incarcerate | Often resolves by one to two years |
| Usual action | Early elective repair | Observe, then repair if it persists or is large |
A hernia can present as an apparent scrotal swelling, so the groin and cough impulse are checked before a hydrocele is diagnosed in any boy. The hernia is repaired early, because it does not resolve and can incarcerate at any time, while the simple hydrocele in an infant is usually observed first and reviewed around one year of age.
Where the exam tries to catch you
Inguinal swellings in children are easy to misname, and the wrong label changes the management.
- Trap: labelling every scrotal swelling in a boy as a hydrocele. Correct: a scrotal hernia can mimic hydrocele, so the groin and cough impulse must be examined before the diagnosis is made.
- Trap: assuming the ovary is never the content in a girl with inguinal swelling. Correct: the ovary is a frequent content of inguinal hernia in girls and can incarcerate, so girls with a groin lump need review.
- Trap: delaying repair of a persistent hydrocele for years. Correct: a hydrocele persisting beyond the first one to two years, or one that is large, is repaired because it may be a communicating hernia.
Frequently asked questions
What is a patent processus vaginalis?
A patent processus vaginalis is a persistent peritoneal outpouching through the inguinal canal that normally closes by term or soon after birth. It is the anatomical basis of both inguinal hernia and communicating hydrocele.
Why are infants prone to incarcerated inguinal hernias?
Infants are prone to incarceration because the inguinal canal is narrow and the hernial sac is small. Premature infants are at particular risk, and an incarcerated hernia can threaten the viability of bowel or ovary.
Which hydroceles should be repaired in children?
Hydroceles that persist beyond about one to two years, or that are large, are repaired because they may be communicating and linked to a hernia. Non-communicating hydroceles frequently resolve in the first year or two and are observed first.
What is the surgical treatment for inguinal hernia in children?
Inguinal hernia in children is treated by high ligation of the hernial sac at the internal inguinal ring, usually as a day-case procedure. Repair is advised soon after diagnosis, because incarceration can occur at any time.
Why is the opposite groin examined during hernia repair?
The opposite groin is examined because a patent processus vaginalis on the other side is common and can later present as a hernia. Surgeons therefore often explore the contralateral side and ligate it when it is patent.