A hydrocele is an abnormal collection of fluid within the remnants of the processus vaginalis:¹

• Simple hydrocele:
  • Accumulation of fluid within the tunica vaginalis.
  • Affects 1-2% of male neonates. A congenital, simple hydrocele usually disappears within the first 1-2 years of life.
  • Causes in older boys and men include trauma, epididymo-orchitis, testicular torsion, hernia, varicocele, and testicular tumour.
• Communicating hydrocele:
  • Persistence of the processus vaginalis allows peritoneal fluid to communicate freely with the scrotal portion of the processus.
  • They are congenital but may first present in older boys and men as a result of increased intra-abdominal pressure, continuous peritoneal dialysis or fluid overload.
• Hydrocele of the cord:
  • The processus vaginalis closes segmentally, trapping fluid within the spermatic cord.
• Abdomino-scrotal hydrocele:
  • Rare; a large hydrocele lies across the internal ring, with both inguinoscrotal and intra-abdominal lobes.

Hydroceles need to be fully investigated if there is any suspicion of an underlying cause. In children, most hydroceles are the communicating type, in which patency of the processus vaginalis allows peritoneal fluid to flow into the scrotum. Non-communicating hydroceles are caused by excessive fluid production within the tunica vaginalis.²

Epidemiology

• Clinically apparent scrotal hydroceles are evident in 6% of term males beyond the newborn period.
• Most paediatric hydroceles are congenital, but rarer causes include malignancy and infection.
• Hydroceles presenting in adults may be secondary to orchitis, epididymitis, tuberculosis, torsion, testicular tumours, trauma, following renal transplantation and post-radiation therapy.³

Presentation

• Scrotal enlargement with a non-tender, cystic swelling.
• Pain is not a feature unless the hydrocele is infected or if there is pain from an underlying cause.
• The testis is usually palpable but may be difficult to palpate if the hydrocele is large.
• A hydrocele lies anterior to and below the testis and will transilluminate. Transillumination is not diagnostic and does not rule out a more urgent scrotal problem.³

Differential diagnosis

Differentiating between a hydrocele and an acute scrotal problem such as testicular torsion or strangulated hernia is very important.³ See separate article Lumps in the Groin and Scrotum.

Investigations

Investigations are not required for simple hydroceles but are essential if there is any doubt in the diagnosis or any suggestion of an underlying cause. Failure to clearly delineate the testis, tenderness on palpation or internal shadows on transillumination are all indications for further investigation:

• Ultrasound can help to determine if any underlying pathology is present. Spermatoceles can be clearly distinguished.
• Duplex sonography may provide information about testicular blood flow when a hydrocele may be associated with chronic torsion of the testis.²
• Diagnostic aspirations should be avoided as they may lead to the spread of malignant cells.
• Serum alpha-fetoprotein and human chorionic gonadotrophin levels help to exclude malignant teratomas or other germ cell tumours.

Management

• Many hydroceles in infancy resolve before the age of 2 years and so observation and non-intervention are usually appropriate for hydroceles in infants. Early surgery in this age group is indicated if there is suspicion of an associated inguinal hernia or underlying testicular pathology.⁴
• Once underlying pathology has been excluded, adults with non-communicating hydroceles can be managed conservatively, with reassurance and a scrotal support.
• Therapeutic aspiration may be required for large hydroceles.
• An exploratory operation is required if the diagnosis is uncertain or underlying pathology cannot be excluded. Other indications for operation are if the hydrocele is large and uncomfortable, becomes infected or repeatedly reaccumulates after aspiration.
• Surgical removal of a hydrocele can be performed by either:²
  • Inguinal approach with ligation of the processus vaginalis high within the internal inguinal ring. This is the procedure of choice for paediatric communicating hydroceles. An inguinal approach is essential if a testicular tumour has been identified preoperatively, or is a possibility. It has been recommended that children younger than 12 years should undergo inguinal exploration for hydrocele repair.⁵
  • Scrotal approach with excision or eversion and suturing of the tunica vaginalis. This is recommended for chronic non-communicating hydroceles. It is possible in children older than 12 years to repair hydroceles through a scrotal incision unless the clinical history is suggestive of a communication.⁵

Complications

• Infection is uncommon.
• Complications of operation:
  • Wound infection.
  • Infertility may occur with bilateral injury to the vas deferens.
  • Testicular atrophy may occur due to injury to the testicular blood supply.
  • Haematoma.
  • Temporary or permanent ilio-inguinal or genitofemoral nerve injury due to entrapment or division during inguinal approaches.
  • Secondary cryptorchidism due to excessive scar formation.
  • Recurrence of the hydrocele after inguinal approaches is usually reactive and resolves within several months.

Prognosis

• The prognosis is dependent on the presence of any underlying cause.
• Most congenital hydroceles resolve by the end of the first year of life.³

Document references

1. Scrotal swellings, Clinical Knowledge Summaries (February 2010)
2. Lee S et al, Hydrocele (Urology perspective), Medscape, Apr 2009
3. Rudkin SE et al; Hydrocele (Emergency Medicine perspective), Medscape, Apr 2010
4. Guidelines on Paediatric Urology, European Society of Urology (2008)
5. Wilson JM, Aaronson DS, Schrader R, et al; Hydrocele in the pediatric patient: inguinal or scrotal approach? J Urol. 2008 Oct;180(4 Suppl):1724-7; discussion 1727-8. Epub 2008 Aug 21. [abstract]

Acknowledgements