Hydrocele occurs when there is a collection of fluid inside the scrotum. This causes one of the testicles to look larger than the other. Most often, hydroceles are found in newborn boys.
This finding is especially seen in those who are born prematurely. Normally, the testicle in a healthy neonate is found within a closed serous covering called the tunica vaginalis of the scrotum.
It is basically a serous pouch that is derived from the peritoneum’s processus vaginalis.
The origin of the tunica vaginalis creates a potential space, which, under normal circumstances, should not communicate with the abdomen’s peritoneal cavity.
The testicles are anatomically found just below the kidneys in the peritoneal cavity during fetal development.
It is from this location that the testicles descend through the inguinal canal and into their final resting place, the scrotum.
During their descent, they are accompanied by the processus vaginalis, which later mostly becomes obliterated in a healthy baby boy and forms a fibrous cord without a lumen. However, the most distal tip of the processus vaginalis remains and forms the serous tunica vaginalis covering the testicles.
Physiologically there should not be any communication between the scrotum and inguinal region with the peritoneal cavity of the abdomen.
This means that abdominal fluids and/or organs should not be able to pass through the inguinal canal into the scrotum. In pathological circumstances, a processus vaginalis that fails to obliterate creates a passage for abdominal fluid to reach the scrotum.
Failure of the processus vaginalis to close fully may be due to several factors, especially those of medical conditions that increase the intra-abdominal pressure.
In many instances, however, the failure is idiopathic.
Types of Hydroceles
Hydroceles may be categorized into two types – communicating and simple.
Communicating hydroceles are a direct consequence of the processus vaginalis failing to close. This leads to the continuous drainage of abdominal fluid into the scrotum.
These hydroceles are similar to hernias (i.e. protruding segments of bowel). However, unlike the small opening of the processus vaginalis seen in hydroceles, hernias tend to occur with much larger openings.
Simple hydroceles are named as such because the processus vaginalis closes, but the extra fluid in the testicles is not absorbed before birth.
Symptoms, Diagnosis and Treatment
The signs and symptoms of hydroceles vary according to the type of hydrocele. Newborn boys with communicating hydrocele will experience a change in the size of the testicle during the course of the day.
This occurs due to fluid entering the scrotum or draining back into the abdominal cavity. In contrast, simple hydroceles exhibit constant scrotal size throughout the day with gradual shrinkage over time. Hydroceles do not cause a baby boy any pain.
Diagnosing hydroceles can be made upon physical examination of the infant. A light may be shone through the swollen testicles - this will appear to be filled with a clear fluid if hydrocele is present. The presence of other tissue in the testicle means that baby may have a hernia.
Most hydroceles in newborn boys tend to go away on their own before the first birthday. Hence, treatment is not usually required. Persisting hydroceles after the first 12 – 24 months of life may require a minor surgical operation that involves draining the fluid and sealing off the passage way. Hydroceles are harmless - they do not cause long term effects or affect fertility later on in life.
Reviewed by Afsaneh Khetrapal, BSc (Hons)