Surgery chapters
Inguinal hernia, hydrocele and acute scrotum in children
Why children get indirect inguinal hernias and hydroceles, when each is repaired, and how to diagnose and manage the acute scrotum, with testicular torsion treated as an emergency until proven otherwise.
- Paediatric inguinal hernias and hydroceles are almost always due to a patent processus vaginalis; hernias are indirect, commoner in premature boys and on the right, and are repaired by herniotomy (no mesh).
- Infant hernias are repaired soon because of the risk of incarceration; most hydroceles resolve and are only operated on if they persist (beyond about 3 years).
- Any acute scrotum is testicular torsion until proven otherwise: explore urgently, ideally within 6 hours, and fix both testes.
On this page
Overview
Groin and scrotal swellings are among the commonest reasons for paediatric surgical referral. Almost all inguinal hernias and hydroceles in children come from one developmental fault: the processus vaginalis fails to close after the testis descends.
The acute scrotum is an emergency because testicular torsion kills the testis within hours. The rule is simple: if torsion cannot be excluded, explore.
Embryology: the processus vaginalis
- The testis forms on the posterior abdominal wall and descends, guided by the gubernaculum. Descent into the scrotum depends on testosterone.
- A finger of peritoneum, the processus vaginalis, goes ahead of the testis through the inguinal canal.
- Normally it closes after birth, leaving only the tunica vaginalis around the testis.
- If it stays widely open, bowel or omentum can enter it: inguinal hernia.
- If it stays open as a narrow channel, only peritoneal fluid passes: communicating (congenital) hydrocele.
- In girls, the equivalent is the canal of Nuck (along the round ligament).
Inguinal hernia in children
Key facts
| Feature | Detail |
|---|---|
| Type | Almost always indirect; direct and femoral hernias are rare in children |
| Who | Much commoner in boys (about 1 in 50) and in premature babies |
| Side | Right more than left (about 2:1); about 15% bilateral |
| Girls | The sac may contain the ovary; bilateral hernias in a phenotypic girl may be androgen insensitivity syndrome (a testis in the sac) |
Presentation
- An intermittent groin or scrotal lump that appears on crying or straining and disappears at rest.
- If not seen, diagnosis rests on a good history and a thickened cord (the "silk sign" of a sac rubbing on itself).
- The lump comes out through the external ring, above and lateral to the pubic tubercle.
In infants a hernia can transilluminate like a hydrocele (thin bowel wall with fluid and gas). Transillumination does not reliably separate them in babies. The key question is whether you can get above the swelling: you can above a hydrocele, not above a hernia.
Incarceration
- An irreducible, firm, tender groin or scrotal lump in an irritable, vomiting infant.
- Highest risk is in the first year of life.
- Can compromise the bowel, testis (cord compression) or ovary.
Management:
- Analgesia (and sedation if needed), then gentle sustained pressure (taxis). Most reduce.
- Wait about 24 hours for oedema to settle, then do the herniotomy in the same admission.
- If it will not reduce, or there are signs of strangulation or peritonitis: emergency surgery.
A paediatric hernia never cures itself. It is repaired promptly once diagnosed, especially in infants, because of the risk of incarceration.
Operation: herniotomy
- Groin crease incision; open the external oblique.
- Find the sac in the cord, separate it from the vas and vessels, then transfix (ligate) and divide it at the deep ring.
- No repair of the posterior wall and no mesh; the abdominal wall is normal, only the sac is the problem.
- Outside the newborn period this is a day-case operation. Laparoscopic repair is possible.
- Premature babies need care because of postoperative apnoea after anaesthesia.
Child = herniotomy (sac only). Adult = herniorrhaphy / hernioplasty (sac plus wall repair, usually mesh).
Hydrocele in children
- Fluid around the testis from a patent but narrow processus vaginalis.
- Painless, non-tender, often bilateral, may be lax or tense; size may change through the day (fills when upright, drains when lying).
- Transilluminates; you can get above it; the testis may be hard to feel inside it.
| Type | Description |
|---|---|
| Communicating (congenital) | Connects with the peritoneal cavity; size varies |
| Encysted hydrocele of the cord | Smooth oval lump along the cord, above the testis; moves down when the testis is pulled |
| Hydrocele of the canal of Nuck | The female version, along the round ligament |
| Abdomino-scrotal | Extends up through the canal into the abdomen |
Management:
- Most resolve as the processus keeps closing.
- If still present after about 3 years of age: operate, by ligating and dividing the patent processus at the deep ring (a herniotomy). Adult-type operations (Lord's, Jaboulay's) are not used.
- A very tense or painful hydrocele in a baby may need earlier repair.
- Bilateral hydroceles: think of ascites (e.g. nephrotic syndrome, ventriculoperitoneal shunt).
A new hydrocele in an older boy may be secondary (torsion, epididymo-orchitis, trauma or a testicular tumour). Do an ultrasound; never aspirate if a tumour is possible.
The acute scrotum
Causes by age
| Age | Most likely cause |
|---|---|
| Newborn | Perinatal (extravaginal) torsion; incarcerated hernia |
| Infant / toddler | Epididymo-orchitis (often with a urinary tract anomaly), incarcerated hernia, idiopathic scrotal oedema |
| Prepubertal (about 7–12) | Torsion of a testicular appendage (hydatid of Morgagni) |
| Adolescent | Testicular torsion (peak) |
Other causes: trauma, haematoma, Henoch–Schönlein purpura, mumps orchitis (older boys), tumour.
Testicular torsion
Pathology:
- In adolescents the twist is intravaginal (inside the tunica vaginalis), because the tunica is attached high on the cord and the testis dangles loosely like the clapper of a bell: the bell-clapper deformity. This is usually bilateral.
- Perinatal torsion is extravaginal: the whole testis and tunica twist before they are fixed to the scrotum.
- Twisting blocks venous outflow first, then arterial inflow, causing infarction.
Clinical features:
- Sudden severe pain in the testis, though some boys feel it mainly in the groin or lower abdomen (T10 referred pain), with nausea and vomiting.
- May have had previous short episodes (intermittent torsion).
- Testis is high-riding, swollen, very tender, sometimes lying horizontally; the twisted cord may be felt.
- Cremasteric reflex absent.
- Lifting the testis does not relieve pain (in epididymitis it may: Prehn sign), though this sign is unreliable.
- Skin redness and swelling may be absent early; usually no fever.
A boy with lower abdominal pain and vomiting may have torsion. Always examine the testes in any boy with abdominal pain.
Management:
- Do not wait for imaging if the clinical picture fits. Colour Doppler ultrasound can help in doubtful cases but can mislead; if in doubt, explore.
- Testicular survival is good if untwisted within about 6 hours (Bailey & Love quotes nearly all saved within 6 hours versus about a fifth at 24 hours). The usual target is exploration within 6–8 hours of onset.
- Scrotal exploration: untwist, assess viability (warm swabs, observe colour and bleeding).
- Viable: fix with non-absorbable sutures (three-point fixation).
- Non-viable: orchidectomy (consent for this beforehand); prosthesis can be offered later.
- Always fix the opposite testis as well, because the deformity is usually bilateral.
Torsion is a clinical diagnosis and a surgical emergency. A normal Doppler scan does not exclude it.
Perinatal torsion is extravaginal; adolescent torsion is intravaginal (bell-clapper).
Torsion of a testicular appendage (hydatid of Morgagni)
- The appendix testis is an embryological remnant attached to the top of the testis (a similar one sits on the epididymis).
- Typically just before puberty, perhaps because the appendage enlarges under gonadotrophins.
- Pain builds up over a day or two; tenderness is localised to the upper pole early on.
- A small dark "blue dot" may be seen through the scrotal skin.
- If the diagnosis is certain: analgesia and rest; it settles. If torsion cannot be excluded, explore and excise the appendage, which gives quick relief.
Epididymo-orchitis
- Bacterial or viral; in infants and toddlers, often linked to a urinary tract anomaly, so investigate the urinary tract (ultrasound, urine culture).
- Gradual onset, fever, urinary symptoms, pyuria. In young boys it is often confirmed only at exploration.
- Treat with antibiotics.
Idiopathic scrotal oedema
- Young boys (about 4–12 years).
- Little pain, red swollen scrotum, often bilateral, spreading to the groin, perineum and penis; testes are normal and not tender.
- Probably allergic (sometimes eosinophilia); settles in a day or two.
"Sudden, high, horizontal, no reflex" = torsion. "Slow, upper pole, blue dot" = hydatid. "Red, swollen, not painful, spreading" = idiopathic scrotal oedema.
Expect: embryology of the patent processus vaginalis, indirect hernia in premature boys and right-sided predominance, herniotomy without mesh, management of incarcerated infant hernia (taxis then delayed repair), timing of hydrocele surgery, transillumination pitfalls, causes of acute scrotum by age, intravaginal versus extravaginal torsion, bell-clapper deformity, 6-hour window, bilateral fixation, blue dot sign of hydatid torsion, and orchidopexy timing for undescended testis.
Quick revision
- Patent processus vaginalis causes both hernia (wide) and hydrocele (narrow).
- Hernia: indirect, boys, premature, right side, 15% bilateral; repair promptly by herniotomy.
- Incarcerated: taxis, wait about 24 hours, then operate; irreducible: emergency.
- Hydrocele: transilluminates, usually resolves; operate if present after about 3 years.
- Torsion: adolescents, intravaginal, bell-clapper; absent cremasteric reflex; explore within 6 hours; fix both sides.
- Neonatal torsion is extravaginal.
- Hydatid torsion: prepubertal, upper pole, blue dot.
- Undescended testis: orchidopexy at 6–12 months; impalpable needs laparoscopy.
Written by The House Job from standard references (Bailey & Love; Basis of Paediatrics).
FAQ
Why are inguinal hernias in children almost always indirect?
They arise from a patent processus vaginalis, which runs through the deep ring and along the canal, so the sac follows the indirect route.
Is mesh used to repair a child's inguinal hernia?
No. The abdominal wall is normal, so only the sac is ligated and divided (herniotomy).
Should a Doppler scan be done before exploring a suspected torsion?
Not if it would delay surgery. Torsion is a clinical diagnosis, and a doubtful case should be explored urgently.
Why is the other testis fixed during surgery for torsion?
The bell-clapper anatomy that allowed the twist is usually present on both sides, so the opposite testis is at risk too.