Appendicitis within the contents of an incarcerated paraumbilical hernia

Abstract

A 30-year-old woman known to have a paraumbilical hernia presented with central abdominal pain and vomiting. On examination, she was tender around the umbilical area, and a lump was felt on the umbilicus with associated skin changes. A CT scan was performed which showed an inflamed appendix within an incarcerated paraumblical hernia.

Background

Acute appendicitis is one of the most common general surgical emergencies. It is, however, not often seen as part of the contents of a paraumbilical or umbilical hernia sac. The appendix is commonly reported in femoral (De Garengeot’s hernia) and inguinal (Amyand’s hernia) hernias as part of both elective and emergencies settings. We present a case of a patient with an incarcerated paraumbilical hernia as well as an inflamed appendix within the hernial sac. The case emphasises the benefits of preoperative imaging to guide surgical planning for an unusual presentation of acute appendicitis.

Case presentation

A 30-year-old morbidly obese woman presented with a one-day history of severe central abdominal pain associated with episodes of vomiting and no additional symptoms. She is known to have paraumbilical hernia. Her medical history included type 2 diabetes mellitus, hypertension, hypercholesterolaemia and osteoarthritis. She had no family history of note. She was a non-smoker and did not drink any alcohol. Her regular medications included antihypertensives and an oral antihyperglycaemic with an allergy to penicillin.

On examination, she was apyrexial and haemodynamically normal. She had epigastric tenderness and a palpable non-reducible mass over the umbilicus with some erythema on the skin. Physical examination was otherwise unremarkable with no guarding or rebound.

Investigations

Haematological and biochemical investigations revealed an elevated white cell count at 16×10⁹/L (4−11×10⁹/L) and a C reactive protein of 206 mg/L (0–5 mg/L), with no other abnormalities and a negative pregnancy test. A CT scan performed showed an inflamed appendix lying within the sac of a paraumbilical hernia, with no associated intra-abdominal free fluid or gas (figure 1).

Figure 1.

Axial CT scan showing an inflamed appendix within the hernial sac.

Differential diagnosis

The differential diagnoses included:

• Incarcerated paraumbilical hernia with or without ischaemic bowel contents.

• Incarcerated paraumbilical hernia with perforated bowel.

The diagnosis was made of an inflamed appendix with an incarcerated paraumbilical hernia following a CT scan.

Treatment

The patient was adequately resuscitated prior to a laparotomy. Intraoperatively, a tight neck of a hernia sac containing pus was found. The appendix was inflamed and had perforated containing a single faecolith. There was no other abnormality found in the bowel or the rest of the abdominal viscera.

An appendicectomy was performed with a non-mesh repair of the hernial defect. The pus specimen sent to microbiology grew Escherichia coli and anaerobes. The patient was managed postoperatively with antibiotics for one week.

Outcome and follow-up

The histopathology from the appendix confirmed the diagnosis of appendicitis with no other features.

The patient made a good postoperative recovery without complications. She was well with no evidence of hernial recurrence at 6 months follow-up.

Discussion

Incarcerated hernias are a common general surgical emergency. Hernia contents are variable from small bowel to omentum and less frequently the appendix, either normal or inflamed. Appendicitis found in a hernia sac is a known phenomenon most commonly occurring in femoral and inguinal hernias, with an incidence of approximately 1%.¹ The total incidence of acute appendicitis in the contents of any hernia sac is estimated at 0.13% of all acute appendicitis presentations.² In addition, there are only five cases of appendicitis in a paraumbilical or umbilical hernia in adults reported in literature.^3–7

It is unclear why some individuals develop appendicitis in a hernia sac. There have been suggestions that certain anatomical variations might pose a risk such as change or loss of the caecal attachment to the peritoneum that would deem the appendix more mobile.² The inflammation of the appendix could be a primary insult or the result of the incarceration itself.⁸ However, this is difficult to assess once acute appendicitis is diagnosed and visualised after the appendix is found within a hernia sac.⁶

One of the challenges with regards to hernia repairs is the risk of wound infection and infected collections due to the inflammatory process caused by appendicitis. There are different approaches to hernia repair. Evidence has shown that although open suture repair is less effective than synthetic mesh repair, it has a lower risk of wound infection in the context of inflamed tissue. However, if local inflammation is minimal and the appendix has not perforated, synthetic or biological meshes yield better long-term results.^{9 10} This case presentation highlights the benefits of emergency perioperative imaging in incarcerated hernias, which is useful for intraoperative planning and management.

Learning points.

• Imaging prior to surgery is beneficial if the clinical condition allows to aid operative planning.

• Hernia repair using sutures or biological mesh is preferred in cases with infection compared with synthetic mesh repair.

• Appendicitis can occur within hernial sacs.