A hydrocoele is a collection of fluid in the scrotum. The fluid accumulates within a thin membrane adjacent to the testicle called the processus or tunica vaginalis. There are two types: non-communicating and communicating hydrocoeles. 

  • Non-communicating hydrocoeles: fluid present in the scrotal compartment that does not communicate with the abdominal cavity. Fluid is trapped within a closed tunica vaginalis. Commonly seen in older children (>5yrs) or adults. 


  • Communicating hydrocoeles: fluid present in the scrotal compartment that transits or communicates with the abdominal cavity. This is due to failure of closre of the tunica vaginalis (called a patent processes vaginalis). Common in infants and young children.

In the pediatric population, this fluid most commonly comes from the abdomen and travels into the scrotum through an opening between the abdomen and scrotal compartment (the patent processus vaginalis).



A hydrocoele is caused when fluid is present around the testicle in the scrotum. When children develop while in the womb, the testicles are developed in the abdomen and pass into scrotum. As the testicles pass into the scrotum, the layer of tissue called the tunica vaginalis, closes behind the testicles to seal them in the scrotal comparment. If this layer doesn not close, fluid can transit between the scrotum and the abdomen and this is called a communicating hydrocoele. A pediatric hydrocoele is a type of infant hernia that contains fluid. 

This communication will close spontaneously in over 70% of children between birth and 2 years of age and the hydrocoele will resolve. If the hydrocoele is non-communicating hydrocoele in children, the majority will resorb over time (6-12 months).


Diagnosis and Evaluation

Hydrocoeles resolve in 70% of patients by the age of 2 years. As a result, patients have serial exams within their first two years of life.

Parents need to watch for fluctuation of the scrotal compartment. Fluctuation is when the scrotum gets bigger or smaller over the course of the day. When the child has been lying down or inactive often the scrotal fluid will migrate back into the abdomen. When they are active and standing, the fluid goes back to the scrotum and it gets larger. If fluctuation (scrotum getting bigger or smaller) after the age of 2 years it is unlikely that this communication will close on its on and should be repair surgically.

Because it is a type of hernia, there is a very small (<1%) chance that bowel can travel down this communication and get trapped. This is termed an incarcerated hernia and is a surgical emergency. Children with an incarcerated hernia often have a lump in the groin which is tense and painful. Often the child appears unwell with nausea and vomiting. These children should be assessed urgently in the emergency room.



Hydrocoeles that fluctuate and persist beyond 2 years are unlikely to close on their own. As they are an infant hernia, they require closure. This is completed with a hydrocoele repair.

Pediatric hydrocoele repair is a daycare surgical procedure that is completed under a general anaesthetic. An incision is made in the groin and the communication between the abdomen and the scrotum is identified and tied off so that the communication is closed. 

Risks of the procedure are small. Common risks include bleeding and infection. Risks specific to this procedure include recurrence of the hydrocoele (0.7-1%). Less common risks (<1%) include injury to the testicle or vas deferens. 


Wed Links

Mayo Clinic for pictures of hydrocoeles 

Epocrates Picture of Hydrocoele


Author: Dr J. Mickelson - last edit May 2013