differentiating a hernia and hydrocoele

Last reviewed 10/2020

Differentiating between an inguinal hernia and a hydrocele

• both a hydrocoele and an indirect inguinal hernia are the result of a patent processus vaginalis. In the case of a hydrocoele, the patent processus is small and only fluid from the peritoneal cavity will be able to pass down the potential space. A communicating hydrocoele is a fluid-filled sac that appears as a transilluminant swelling around the testis (true hydrocoele) as there is continuity between the processus vaginalis and tunica vaginalis. The main differential of a transilluminable swelling is bowel within the processus vaginalis. If the swelling occurs adjacent to the spermatic cord then this is termed an encysted hydrocoele. There may be a history of the hydrocoele appearing to enlarge during the day and then disappearing at night. This relates to the effects of gravity on filling the hydrocoele. The communication between the fluid-filled sac and the inguinal ring is so small in a hydrocoele that is is difficult to detect clinically
  
  
• in a congenital inguinal hernia, the proximal opening of the processus is wide. Historically, there may a story of abdominal pain, constipation, nausea or vomiting; these are indicative of incarceration or strangulation of the hernia. Clinically, it may present as a lump in groin when the intraabdominal pressure rises e.g. when the child cries, or as a persistent swelling extending from the groin to the vulva or scrotum. With a hernia, the communication can be palpable so that one could ascertain whether the lump originates from the deep inguinal ring. This manoeuvre can be painful to the patient. Hernias do not transilluminate unless they contain thin-walled bowel. An examiner cannot feel a superior border to a hernia on palpation. Bowel sounds on ausculation over the mass are virtually pathognomic of a hernia