Incarceration of a hernia occurs when the abdominal contents become trapped within the patent process vaginalis and do not retract above the inguinal ring (Fig. 47-1). Although most often it is small bowel that becomes incarcerated, any abdominal contents are at risk. In females, this can include the ovary and fallopian tube. A hernia becomes strangulated when the blood supply becomes compromised. Initially, the flow to the lymphatics and veins is affected leading to engorgement of the trapped viscera and eventually reducing or stopping the arterial flow. This can ultimately lead to ischemia, gangrene, and perforation of the affected viscera. Blood flow to the testis can also be reduced leading to ischemic damage. Incarceration is most frequent in the first 6 months of life and is comparatively rare after 5 years of age.14
With an incarcerated hernia, the child may develop fussiness, poor feeding, abdominal pain, or vomiting. A tender, nonfluctuant, palpable mass will be present in the inguinal area and may extend into the scrotum or labia. As strangulation ensues, bilious emesis from obstruction, blood in the stool, and fever along with signs of peritonitis and sepsis may occur. Strangulation can arise within 2 hours from the onset of incarceration.