Medizinisches Rätsel - Die Antwort

Rajaraman Durai, specialist registrar¹, Sumantra Kumar, consultant radiologist ², Sha-Nawaz Ruhomauly, consultant surgeon¹, Happy Hoque, consultant surgeon¹

¹ Department of Surgery, Queen Mary’s Hospital, Sidcup, Kent, ² Department of Radiology Queen Mary’s Hospital, Sidcup, Kent

BMJ 2008;337:a1953

dr_durai@yahoo.com

1 The computed tomogram
The diagnosis of acute appendicitis is often made on the basis of clinical features alone. Acute appendicitis is the commonest cause of acute abdominal pain in children and adults.^{1 2} In 2006-7, 42 882 patients were admitted with acute appendicitis to English NHS hospitals (www.hesonline.nhs.uk). Early appendicitis may resolve with antibiotics or it may progress to phlegmon, perforation, and abscess formation. If perforation occurs without localisation, it may present with diffuse peritonitis. The incidence of perforated appendicitis varies between 16-30%.^{3 4} Because very young patients may not be able to communicate, and older patients may present with non-specific signs, the risk of perforation is higher in these groups as diagnosis may be delayed.⁵ Appendicular perforation is more likely to occur on the third day.⁶ In a study on 427 patients with appendicitis,⁷ 14 (3.25%) presented with diffuse peritonitis. In the case in question, the patient presented ten days after his abdominal pain had developed. The computed tomogram showed a thin walled gall bladder containing a few calcified gallstones without any signs of acute cholecystitis (figure 2). It also showed an 11x7 cm appendicular abscess with an air fluid level . It was adherent to the right anterior abdominal wall, medial to the caecum and the ascending colon. The terminal ileum and the ileocaecal junction seemed normal without any thickening to indicate Crohn’s disease.

2 Diagnosis
The patient had a history of right iliac fossa pain with raised inflammatory markers and a high Alvarado score. The computed tomogram confirmed an appendicular (perityphlitic) abscess. No evidence was found for any other cause for the abscess.

Midline to right iliac fossa migratory pain, in conjunction with increased inflammatory markers and right iliac fossa peritonism, favours the diagnosis of appendicitis.⁸ The initial periumbilical pain is referred from the inflamed viscera. The pain migrates to the right iliac fossa when there is irritation of the parietal peritoneum. Several scoring systems are used for right iliac fossa pain to help in the diagnosis of appendicitis. The Alvarado score is commonly used, and when the score is maximal (10/10), the diagnostic accuracy for appendicitis may reach 100%.⁹ Ultrasonography¹⁰ or computed tomography¹¹ may be useful in difficult cases. Ultrasonography is often used in women and children. Computed tomography may help to reduce the negative appendicectomy rate to 3.8%.¹¹

3 Treatment
Although the standard approach for appendicitis is open appendicetomy, antibiotics alone may settle appendicitis. A recent randomised controlled trial on acute appendicitis¹³ compared the outcomes of operative treatment (124 patients) with antibiotic treatment (128 patients). In the antibiotic group, 18 patients failed to improve and required appendicetomy. The remaining 110 patients were followed up for a year, but only 14% had recurrent symptoms.

Appendicitis has a high risk of rupture in very young and elderly patients because it may be difficult to diagnose. Escherichia coli and Bacteroides fragilis are commonly isolated organisms from appendicular abscesses.¹⁴ Abscesses larger than 3 cm can be considered serious^{15 16} and are unlikely to resolve with antibiotics alone.¹⁷ Open drainage or appendicectomy can lead to an infection of the wound in up to 16% of patients.¹⁸ In all cases of right iliac fossa mass, a carcinoma of the colon should be excluded.^{19 20} In this case the patient’s abscess was drained radiologically under the guidance of ultrasonography. The patient continued on intravenous cefuroxime and metronidazole, which had been started on admission to reduce the risk of systemic sepsis. The pus grew Enterococcus fecalis. An ultrasonography scan was repeated a week after the drain had been placed, and it showed no residual abscess. The drain was then removed.

The differential diagnosis for the aetiology of a right iliac fossa abscess includes appendicular perforation, caecal diverticular perforation, perforated caecal cancer and perforated ileum from Crohn’s disease. A computed tomogram may help in identifying the cause. Once the acute situation resolves, a colonoscopy or barium study may be required to exclude caecal malignancy.

Several options are available for an appendicular abscess. Firstly, radiological drainage and antibiotics followed by interval appendicectomy. The recent trend is to avoid interval appendicetomy. If there is no recurrence of appendicitis in the first six months, the patient may not benefit from interval appendicectomy²¹ because the appendix may become fibrotic and the risk of recurrence reduces (10%).²² Another option is open drainage of the abscess and attempted appendicectomy at the same time.¹⁸ This may be difficult because of the presence of adhesions and pus from the unresolved inflammatory process. The likelihood of complications such as bowel injury and wound infection is increased. Appendicular abscess is associated with a mortality of 2.9%.²³

Laparoscopy is useful in the diagnosis and treatment of suspected appendicitis.^{3 24} The operating time may be slightly longer than at open operation, but no major increase in the formation of intra-abdominal abscesses occurs in uncomplicated appendicitis.²⁵ The laparoscopic approach reduces rates of wound infection and leads to an earlier recovery. Infection of the surgical site after laparoscopy can be reduced by stapled transection of the appendix and closure of the appendicular stump.²⁶

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