Hydrocele

Etiology

There are four basic mechanisms by which hydrocele can develop. These are mentioned below:1. Connection with the peritoneal cavity through a patent processes vaginalis (congenital).2. Excessive production of fluid (secondary hydrocele).3. Defective absorption of fluid. 4. Interference with the lymphatic drainage of scrotal structures as in filarial hydroceles.  In children, patency of processus vaginalis, allowing peritoneal fluid to flow into the scrotum, is the main cause of hydrocele. However, in adults, filariasis caused by Wuchereria bancrofti is the main culprit globally, affecting 120 million people in more than 73 countries.[3] This is not true in the United States, where iatrogenic causes (either trauma or post-herniorrhaphy complications) predominate.[4]

Epidemiology

At birth, around 80-90% of term male infants possess a patent processus vaginalis. This figure declines steadily to settle at approximately 25-40% at two years of age.

Autopsy data indicates that processus vaginalis tends to remain patent at a frequency of 20% until later in adult life. However, only 6% of these become clinically evident beyond the newborn period. Risk factors of hydrocele include breech presentation, low birth weight, and gestational progestin use.

History and Physical

The majority of patients with hydrocele present with the complaint of painless scrotal swelling rendering the testes impalpable with positive transillumination and fluctuation. The examiner should look at this swelling in both the supine and upright positions. During the examination, the provider should ask the following set of three questions:

1. Is it possible to reach above the swelling and palpate the cord? If no, this could represent a hydrocele (congenital or infantile) or a hernia. A hernia can be differentiated from hydrocele in terms of having expansile cough impulse and reducibility but lacking transillumination and fluctuation.

2. Does the swelling arise from testis or epididymis or encase both of these structures. Hydroceles tend to surround both testes and epididymis, rendering them impalpable.

3. Does the swelling transilluminate?[5]

The primary hydrocele is predominant in middle and later life. A common predisposing factor for hydrocele is residing in a warm climate. As it is painless, it acquires a prodigious size before the patient seeks medical attention. In contrast, the secondary hydrocele is generally smaller, with the exception of filarial hydrocele.

Congenital hydrocele tends to be intermittent as it usually reduces when lying flat due to drainage of hydrocele fluid into the peritoneum. However, applying pressure on the congenital hydrocele does not reduce it.

An encysted hydrocele feels like a smooth oval-shaped swelling near the spermatic cord. It may feel like an inguinal hernia and therefore, should be differentiated. In female patients, the hydrocele of the canal of Nuck is a rare condition in which a cyst develops anterior to the round ligament of the uterus.[6]

Evaluation

Hydroceles can be diagnosed on clinical grounds, as discussed in the history and physical section. However, in the presence of any concomitant medical condition or to exclude other medical or surgical conditions, further studies, including laboratory or imaging, should be considered.

Laboratory Studies

These are indicated to exclude other surgical or medical conditions that may be in the differential diagnosis.

• Inguinal Hernia: Laboratory tests are usually not indicated, but in the case of an incarcerated inguinal hernia, which can mimic hydrocele, leukocytosis can aid in the differentiation. Negative transillumination and palpable bowel at the deep ring on the digital examination is more consistent with an inguinal hernia.
• Testicular Tumor: Serum alpha-fetoprotein and human chorionic gonadotropin (hCG) levels are indicated if there is suspicion of malignant teratomas or other germ cell tumors.
• Epididymitis/Orchitis: These conditions can lead to secondary or reactive hydroceles. In such cases, urinalysis and urine culture may be useful.

Imaging Studies

These are helpful in diagnosing and evaluating hydrocele. They can also assess for underlying processes such as epididymitis, testicular torsion, or testicular tumor.

Ultrasonography: Scrotal pain or failure to delineate the testicular anatomy on palpation is an indication for ultrasonography as it provides excellent detail of testicular parenchyma. During the ultrasonography examination, hydrocele appears as an anechoic or echolucent area surrounding the testis. Ultrasonography could also help with the sizing and characterization of the hydrocele. Spermatoceles, testicular tumors, and testicular atrophy can be easily distinguished via ultrasonography. The patient should be examined in both supine and upright positions as hydrocele has a tendency to reduce into the abdomen based on the position of the patient.[7]        

Duplex Ultrasonography: It provides information regarding testicular blood flow, which will be reduced or absent in hydroceles resulting from testicular torsions. However, in the case of hydroceles secondary to epididymitis, the epididymal flow would be increased. In addition, duplex studies help identify the Valsalva augmented regurgitant flow in varicoceles.

Plain Abdominal Radiography: In an incarcerated inguinal hernia, one may see gas overlying the groin.

Treatment / Management

Surgery is the treatment of choice for hydrocele, and it is warranted when hydrocele becomes complicated or symptomatic. For congenital hydroceles, herniotomy is performed, provided they do not resolve spontaneously. On the other hand, acquired hydroceles subside when the primary underlying condition resolves.

There are two common surgical approaches available for hydrocelectomy:

1. Plication: This technique is suitable for thin-walled hydroceles. As there is minimal dissection, the risk of hematocele or infection is significantly reduced. Lord plication involves the tunica being bunched into a ruff by applying a series of multiple interrupted chromic catgut sutures for the sac to form fibrous tissue.

2. Excision and Eversion: This technique is suitable for large thick-walled hydroceles and chyloceles.[8] It involves subtotal excision of the tunica vaginalis and everting the sac behind the testes followed by placing the testes in a newly created pocket between the fascial layers of the scrotum (Jaboulay procedure). Particular consideration is taken not to damage epididymis, testicular vessels, or ductus deferens.

Aspiration 

This is another method to treat hydrocele, particularly in patients who cannot tolerate surgery. However, hydrocele fluid almost always reaccumulates within a week or so.[9] In addition, the risk of hematocele and infection after aspiration is high. Aspiration followed by an injection of a sclerosant (tetracycline or doxycycline) has been proven to be effective but painful.[10](A1)

Complications of Surgery

• Reactionary hemorrhage
• Pyocele
• Infection
• Sinus formation
• Recurrent hydrocele

Differential Diagnosis

Differential diagnoses of hydrocele include:

• Inguinal hernia
• Epididymal cyst
• Spermatocele
• Testicular tumor
• Scrotal edema
• Varicocele

Prognosis

The prognosis of the congenital hydrocele is excellent, while that of the adult-onset hydrocele depends on the underlying cause.

Congenital hydroceles tend to resolve spontaneously by the end of the first year of life. If persistent, they can be corrected surgically with a high success rate and a good long-term prognosis. In experienced hands, hydrocele repair carries a very low risk of testicular damage or recurrence.

The prognosis of the adult-onset hydrocele is mainly dependent on the underlying cause. For instance, filarial hydrocele's prognosis depends on its size and the severity of lymphatic obstruction.

Complications

Complications are attributable to the pathology itself and the treatment administered. Some of them are as follows:

• Infection
• Pyocele
• Haematocele
• Atrophy of testes
• Infertility (resulting from the spermatogenesis halt due to increased pressure on the blood supply on the testis from edema)[11]
• Rupture[12][13]
• Hernia of hydrocele (rare)