Acute appendicitis results from bacterial invasion usually distal to an obstruction of the lumen. The obstruction is caused by faecaliths, seeds or worms in the lumen or by invasion of the appendix wall by parasites, such as amoeba or schistosomes. Lymphoid hyperplasia following a viral infection has also been implicated. Untreated, the infection progresses to:

Clinical features

Symptoms include:

Physical findings include:

The differential diagnosis includes:

Appendicular mass

This is caused by inflammation and swelling of the appendix, caecum, omentum and distal part of the terminal ileum. Treat conservatively with rest, antibiotics, analgesics and fluids. If the patient’s pain and fever either continue or recur, the mass probably includes an abscess which should be incised and drained.

Technique

Emergency appendectomy

::	With the patient in the supine position, place an 8–10 cm incision over McBurney’s point or the point of maximum tenderness you have previously marked (Figure 7.15). Note that this incision should be smaller in a child. Deepen the incision to the level of the external oblique aponeurosis and cut through this in line with its fibres (Figure 7.16). Split the underlying muscles along the lines of their fibres using blunt dissection with scissors and large straight artery forceps (Figure 7.17). Use a “gridiron” technique by splitting and retracting the muscle layers until the extraperitoneal fat and the peritoneum are exposed. Lift the peritoneum with two pairs of artery forceps to form a tent and squeeze this with your fingers to displace the underlying viscera. Incise the peritoneum between the two pairs of artery forceps.
Figure 7.15
Figure 7.16
Figure 7.17
::	Aspirate any free peritoneal fluid and take a specimen for bacteriological culture. If the appendix is visible, pick it up with a non-toothed or a Babcock forceps. The appendix may be delivered by gently lifting the caecum with the anterior taeniae coli. An inflamed appendix is fragile so deliver it into the wound with great care. The position of the appendix is variable (Figures 7.18 and 7.19). Locate it by following the taeniae coli to the base of the caecum and lifting both the caecum and the appendix into the wound (Figure 7.20).
Figure 7.18
Figure 7.19
Figure 7.20
::	Divide the mesoappendix (containing the appendicular artery) between artery forceps close to the base of the appendix. Ligate it with 0 absorbable suture (Figures 7.21–7.23). Clamp the base of the appendix to crush the wall and reapply the clamp a little further distally (Figures 7.24 and 7.25). Ligate the crushed appendix with 2/0 absorbable suture. Cut the ends of the ligature fairly short and hold them with forceps to help invaginate the appendix stump. Insert a 2/0 absorbable, purse-string suture in the caecum around the base of the appendix (Figure 7.26). Divide the appendix between the ligature and the clamp and invaginate the stump as the purse-string is tightened and tied over it (Figure 7.27). The purse-string is traditional, but optional. Simple ligation is adequate and the preferred technique if insertion of a purse-string is at all difficult.
Figure 7.21
Figure 7.22
Figure 7.23
Figure 7.24
Figure 7.25
Figure 7.26
Figure 7.27
::	Close the abdominal wound using: • Continuous 2/0 absorbable suture for the peritoneum • Interrupted 0 absorbable sutures for the split muscle fibres • Interrupted or continuous 0 absorbable for the external oblique aponeurosis • Interrupted 2/0 monofilament non-absorbable for the skin. If there is severe inflammation or wound contamination, do not close the skin, but pack the skin and subcutaneous layers with damp saline gauze for delayed primary closure.

Intraoperative problems

Intraoperative problems include:

Adherent and retrocaecal appendix

Mobilize the caecum by dividing its retroperitoneal attachment and then excise the appendix in a retrograde manner. Ligate and divide the base of the appendix, then invaginate the stump, ligate the vessels in the mesoappendix, and finally remove the appendix.

Appendicular abscess

Treat the abscess with incision and drainage. Consider interval appendectomy if symptoms recur.