The causes of hydroceles are legion. In children, most hydroceles are of
the communicating type, in which patency of the processus vaginalis
allows peritoneal fluid to flow into the scrotum, particularly during
Valsalva. In the adult population, filariasis, a parasitic infection
caused by Wuchereria bancrofti, accounts for most causes of hydroceles
Following laparoscopic or transplant surgery in males, inadequate
irrigation fluid aspiration may cause hydroceles in patients with a
patent processus vaginalis or a small hernia. Careful aspiration of
fluid at the end of laparoscopic procedures helps prevent this
complication. In noncommunicating hydroceles, for both children and
adults, the balance between fluid production within the tunica and the
fluid absorption is altered.
The pathophysiology of hydroceles requires an imbalance of scrotal fluid
production and absorption. This imbalance can be divided further into
exogenous fluid sources or intrinsic fluid production.
Alternatively, hydroceles can be divided into those that represent a
persistent communication with the abdominal cavity and those that do
not. Fluid excesses are from exogenous sources (the abdomen) in
communicating hydroceles, whereas noncommunicating hydroceles develop
increased scrotal fluid from abnormal intrinsic scrotal fluid shifts.