Types of hydrocele

It is always worrying when something is wrong with our children, but it can be a particular concern when the condition affects their genitals. Swollen testicles can indicate the presence of a hydrocele. But what is this condition and how does it happen? Esteemed paediatric urologist Mr Andrew Robb explains.

What is a hydrocele?

A hydrocele is simply an abnormal amount of fluid surrounding the testicle.

Are there different types of hydrocele?

There are two types of hydroceles:

Congenital (present at birth)
Acquired (develops after birth)

It is not possible to tell from examination or scanning what type of hydrocele a patient has. However, there is evidence that boys under the age of 12 will, in general, have a congenital hydrocele, whilst boys over the age of 12 are more likely to have an acquired hydrocele.

Congenital hydroceles

The most common type of hydrocele in boys is the congenital variety.

Before birth, the testicles develop inside the baby’s tummy. The testicles then pass through the tummy wall (through the inguinal canal) and then down into the scrotum. To help the testicles travel down to the scrotum, some tissue from the lining of the inside of the tummy goes down as well, which acts like a slide. This is called the ‘processus vaginalis’. It is like the finger of a glove. Once the testicle is in the scrotum this tissue forms a protective layer around the testicle and the connection with the tummy normally closes. This connection is open in nearly all boys at birth and closes in most boys during the first year of life. We call this open connection a ‘patent processus vaginalis’ (PPV).

In the vast majority of boys, although this connection is open, it does not cause any symptoms and you would not know that it is there. If fluid starts to go down this connection and surrounds the testicle, this causes a hydrocele. The fluid comes from the natural fluid that is produced on the outside of the intestines to lubricate it (peritoneal fluid). If the intestines start to go down the connection then this is called an inguinal hernia.

Girls also have a processus vaginalis, which leaves the tummy through their inguinal canal. The processus vaginalis goes on to form a structure called the round ligament in girls. If the opening inside the processus vaginalis does not close, fluid can accumulate in it. This is called a hydrocele of the canal of Nuck.

Acquired hydroceles

An acquired hydrocele is seen more commonly in older boys and in adults. It occurs when the fluid in the hydrocele does not come from the tummy. There are a number of possible causes such as:

Trauma
Infection
Torsion of the testicle or one of the other structures in the scrotum.
Tumour

Sometimes no cause for the build-up of fluid is found.

What are the symptoms of a hydrocele?

The main symptom of a hydrocele is a swelling in the scrotum. The swelling may extend up into the groin.

Parents will often notice that the size of the swelling changes. Often, they note it is bigger in the evening. Hydroceles in children may also get bigger when the child has a viral-type illness. They may also notice that the swelling in the scrotum appears to have a blue colour.

Hydroceles do not tend to cause any other symptoms, such as pain.

If the hydrocele is acquired (i.e. caused by another condition), then the underlying problem may cause symptoms – for example, infection or a torsion may cause pain.