Teaching Case

A 8o-year-old male patient with a known left-sided inguinoscrotal hernia presented with increasing pain and swelling of the left inguinal region for 3 days. At clinical exam the hernia was not reducible, and the abdomen was soft and not tender. Incarcerated hernia was suspected, and a CT scan was performed.

Contrast-enhanced CT scan of the abdomen and pelvis showed a left-sided inguinoscrotal hernia (Figure 1a, 1b). The hernia sac contained a loop of the sigmoid colon without signs of bowel obstruction. There was pericolic stranding, segmental thickening of bowel wall, and increased enhancement of the colonic wall with an inner and an outer high-attenuation layer (Figure 1a). Multiple diverticula were present in the herniated bowel segment and the described changes were in keeping with acute diverticulitis (Figure 2a, 2b, 2c). There were no abscesses or signs of perforation.

Sigmoid colon diverticulitis and inguinal hernias are common entities in emergency medicine. However, diverticulitis within a hernia is rarely seen [1]. On the right side it is not uncommon to find the appendix in an inguinal or femoral hernia (Amyand and De Garengeot hernia, respectively). Occasionally appendicitis may occur within these hernias [1,2]. Diverticulitis is characterised by inflammation of the outpouchings of the bowel wall. It may occur in small and large bowel, though more commonly presents in the left colon; transverse colon diverticulitis simulating inguinal hernia strangulation has been also reported [3]. Imaging findings of diverticulitis include oedematous thickening of the bowel wall with inflammatory changes within the adjacent mesenteric fat. In complicated cases where the inflammatory process has led to bowel perforation free intraperitoneal air will be present along with abscess formation [4]. Furthermore, longstanding diverticulitis is known to cause fistulae to the bladder or the vagina. Occasionally, the sigmoid colon is trapped in an inguinal hernia or makes up the wall of a sliding hernia on the left side. Rarely does one suspect a primary colonic process leading to inguinal symptoms [5-7]. More recent studies have associated specific host immune responses, gut microbiota imbalance and therefore low-grade inflammation, genetic susceptibility, environment, colonic motility and visceral sensitivity in the pathogenesis of this disease [6]. The present case is an example of a common disease in an unusual location. Diverticulitis was not suspected at clinical examination, and the diagnosis was established after the CT scan. As incarcerated hernia was suspected ultrasound (US) could have been used as the primary imaging method. With US it would have been possible to diagnose both the hernia as well as the inflammatory changes. The option of using US is especially important in younger patients due to the inherent radiation issues of CT. The imaging findings encountered at CT were classical for acute uncomplicated diverticulitis without signs of perforation or abscess formation. The patient was managed with antibiotics and made a full recovery. Most of the cases can be treated conservatively by antibiotics and adequate diet. Complicated cases with perforation and abscesses need surgical resection and/or drainage. Furthermore, chronic/recurrent diverticulitis can cause stenosis and eventually bowel obstruction. Fistula to the urinary bladder or vagina may also occur [7]. Such cases also need surgical treatment. However, in treatment planning performance status and comorbidities are important factors that must be taken into account. In conclusion, diverticulitis may occur within a hernia sac and should be taken into consideration when there is isolated pain at a hernia site. Written informed patient consent for publication has been obtained.