Hydrocele

A hydrocele is an abnormal collection of serous fluid within a part of the processus vaginalis - most commonly the tunica vaginalis surrounding the testis, and occasionally along the spermatic cord.

Epidemiology

Affects approximately 1% of adult men
More than 80% of newborn boys have a patent processus vaginalis at birth
Most close spontaneously within 18 months of age
Primary (idiopathic) hydroceles are most common; secondary hydroceles typically occur in men >40 years

Embryology & Pathophysiology

The processus vaginalis is a diverticulum of the peritoneal cavity that descends with the testes into the scrotum via the inguinal canal around the 28th week of gestation, with gradual closure through infancy and childhood.

Fluid accumulates due to excessive production and/or defective absorption by the tunica vaginalis, often from disruption of lymphatic drainage.

Classification

Types of hydrocele: (a) vaginal/primary, (b) infantile, (c) congenital/communicating, (d) hydrocele of the cord

Bailey & Love's, Fig. 86.8: Types of hydrocele

Type	Description
(a) Vaginal (primary/non-communicating)	Processus vaginalis is closed; fluid accumulates within tunica vaginalis due to imbalance in production/absorption. Most common type globally.
(b) Infantile hydrocele	Distal processus closes correctly but mid-portion remains patent; proximal end is open, communicating with tunica vaginalis.
(c) Congenital (communicating)	Patent processus vaginalis allows free flow of peritoneal fluid into the scrotum; associated with indirect inguinal hernias.
(d) Hydrocele of the cord	Both proximal and distal ends of processus close but mid-portion remains patent, forming a cyst along the spermatic cord.

Abdominoscrotal hydrocele is a rare variant (1.25% of all hydroceles), bilateral in ~30% of cases, where a non-communicating scrotal mass extends upward into the abdomen.

Etiology

Primary (idiopathic): No underlying cause found. Most common in adults.

Secondary: Occurs at any age, may present acutely. Causes include:

Epididymo-orchitis / infection (including filariasis - major cause globally)
Testicular torsion
Trauma
Testicular neoplasm
Radiotherapy

Important: If a tumour is suspected, do NOT aspirate the hydrocele - risk of malignant needle-track implantation.

Post-varicocelectomy hydrocele: Complication in 3-33% (average ~7%) of non-microscopic varicocelectomy, caused by lymphatic obstruction. Microsurgical technique almost eliminates this risk.

Filarial hydrocele: Accounts for up to 80% of hydroceles in tropical countries (endemic Wuchereria bancrofti). Follows repeated filarial epididymo-orchitis. May contain chylous fluid (chylocele) from ruptured lymphatic varices.

Clinical Features

Examination should be performed in both upright and supine positions. Ask three key questions:

Can you get above the swelling? - A hydrocele allows palpation of a normal spermatic cord above it (unlike an inguino-scrotal hernia)
Are the testis and epididymis palpable? - A hydrocele encloses both structures, making them impalpable
Does it transilluminate? - Hydroceles are typically brilliantly translucent

Presentation:

Usually painless scrotal swelling - may reach large size before presentation
Smooth, fluctuant, tense swelling
An acute hydrocele in a young man warrants suspicion for testicular tumour
Congenital hydrocele may be intermittent (fluid drains back to peritoneum when lying flat)
Hydrocele of the cord - smooth oval swelling above the testis near the cord; moves downward when testis is pulled (differentiates from inguinal hernia)
Hydrocele of the canal of Nuck - female equivalent; cyst along the round ligament, at least partially within the inguinal canal

Investigations

Scrotal ultrasound - investigation of choice; valuable when testis/epididymis is impalpable, and to exclude underlying testicular pathology (especially malignancy)
Fluid analysis if aspirated (protein concentration helps distinguish causes)

Treatment

Conservative

Small, asymptomatic hydroceles require no treatment
Congenital hydroceles in infants - watchful waiting; most resolve spontaneously by 18 months

Surgical (main treatment for symptomatic acquired hydroceles)

Three established surgical techniques:

Procedure	Principle	Indication
Lord's operation (plication)	Sac is gathered and sutured with multiple radial stitches without excision	Thin-walled sac; minimal dissection, reduced haematoma risk
Jaboulay's procedure (eversion)	Sac is everted and sutured behind the epididymis (bottleneck suture)	Moderate-thickness sac; most widely used
Excision	Sac is excised and edges oversewn	Thick-walled or recurrent hydrocele; highest haematoma risk

Congenital hydroceles are treated by herniotomy (ligation of patent processus vaginalis) through an inguinal incision
In infants, surgery is deferred unless the hydrocele persists beyond 2 years or enlarges

Aspiration

Simple but fluid always reaccumulates within days to weeks
Reserved for men unfit for surgery (can be done under local anaesthetic)
Risk of haematocele formation
Sclerotherapy (e.g., tetracycline injection) may be added - effective but painful

Filarial/Chylocele

Acute: rest and aspiration
Chronic: excision of the sac

Differential Diagnosis of Scrotal Swelling

Feature	Hydrocele	Epididymal cyst	Varicocele	Inguinoscrotal hernia	Testicular tumour
Can get above	Yes	Yes	Yes	No	Yes
Transillumination	Bright	Bright	No	No	No
Relation to testis	Surrounds testis	Separate from testis	Above/behind testis	Separate	Part of testis

Key Points

Hydroceles surround the testis and transilluminate brightly
Ultrasound is essential when testis/epididymis is impalpable
Testicular malignancy is an uncommon but important secondary cause - exclude by ultrasound
Surgery is the mainstay of treatment for symptomatic cases
Never aspirate if malignancy is suspected
In tropical regions, filariasis (W. bancrofti) is the dominant cause

Sources: Bailey and Love's Short Practice of Surgery, 28th Ed., Ch. 86; Campbell-Walsh-Wein Urology, Ch. 37, 44; Mulholland & Greenfield's Surgery, 7th Ed.

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