Clinical Presentation of Acute Appendicitis: Clinical Signs—Laboratory Findings—Clinical Scores, Alvarado Score and Derivate Scores

Abstract

Appendicectomy is the most commonly performed emergency operation worldwide with a lifetime risk of appendicitis of 8.6% in males and 6.7% in females (Flum and Koepsell 2002; Addiss et al. 1990). The diagnosis of acute appendicitis is predominantly based on clinical findings (Humes and Simpson 2006). Whilst a clinical diagnosis can often be made there are groups of patients in whom the clinical diagnosis is difficult and these patients provide a degree of diagnostic uncertainty. Studies reporting the mortality associated with appendicitis have demonstrated a significant increase in mortality associated with perforation (Blomqvist et al. 2001). The rate of perforation is reported to increase by 5% per 12 h period 36 h after the onset of symptoms, therefore, expedient diagnosis and treatment are required (Bickell et al. 2006). High rates of negative appendicectomy (operation without histological confirmation of appendicitis) have been reported with some groups such as females of reproductive age having rates of up to 26% (Flum et al. 2001). Delayed or incorrect diagnosis therefore has both clinical and economic consequences (Flum and Koepsell 2002) and this has resulted in considerable research to identify clinical, laboratory and radiological findings that are diagnostic of appendicitis and the development of clinical scoring systems (some computer aided) to guide the clinician in making the correct diagnosis. Thus reducing the delay in diagnosis and decreasing the rates of negative appendicectomy. There is evidence that despite the introduction of new specialist tests that the diagnosis of appendicitis has not improved on a population level (Flum et al. 2001). This chapter aims to outline the presentation, investigation and diagnosis of acute appendicitis.