10/11/2015 Acute appendicitis in adults: Diagnostic evaluation http://aplicacionesbiblioteca.udea.edu.co:4560/contents/acuteappendicitisinadultsdiagnosticevaluation?topicKey=SURG%2F96169&elapsedTimeMs=… 1/15 Official reprint from UpToDate www.uptodate.com ©2015 UpToDate Author Ronald F Martin, MD Section Editor Martin Weiser, MD Deputy Editor Wenliang Chen, MD, PhD Acute appendicitis in adults: Diagnostic evaluation All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Oct 2015. | This topic last updated: Jul 24, 2014. INTRODUCTION — The diagnosis of acute appendicitis is typically based upon the findings from the medical history and clinical examination and is supported by the laboratory and/or imaging findings. This topic will review the diagnostic studies, including radiographic studies and laboratory tests that can assist in establishing the diagnosis of acute appendicitis in the adult. The clinical manifestations of acute appendicitis and the operative and nonoperative management are reviewed as separate topics. (See "Acute appendicitis in adults: Clinical manifestations and differential diagnosis" and "Management of acute appendicitis in adults" .) DIAGNOSIS — The diagnosis of acute appendicitis is generally made from the history and clinical examination; the diagnosis is supported by the laboratory and/or imaging findings. The patient presenting with acute abdominal pain should undergo a thorough physical examination, including a digital rectal examination. Women should undergo a pelvic examination. (See "History and physical examination in adults with abdominal pain" .) An experienced examiner can make the correct diagnosis of appendicitis without imaging [1 ]. Several studies have found the diagnostic accuracy of clinical evaluation alone to be 75 to 90 percent [25 ]. The diagnostic accuracy of the clinical examination may depend on the experience of the examining clinician [611 ]. Patients in whom appendicitis is considered to be extremely likely after assessment by an experienced clinician should proceed directly to appendectomy without further radiologic testing. (See "Management of acute appendicitis in adults" .) The diagnosis of acute appendicitis can be difficult and a delay can result in perforation rates as high as 80 percent [12,13 ]. However, a retrospective review of 9048 adults with acute appendicitis found that the mean time from presentation to operation (8.6 hours) was not associated with risk of perforation [14 ]. Factors associated with increased risk of perforation included male gender (RR 1.24, 95% CI 1.081.43), increasing age (RR 1.04, 95% CI 1.081.43), three or more comorbid illnesses (RR 2.8, 95% CI 1.363.49), and lack of medical insurance coverage (RR 1.43, 95% CI 1.241.66). The challenging clinical settings include [15 ]: No single feature or combination of features is a highly accurate predictor of acute appendicitis, although prediction rules based upon combinations of features may have some clinical utility [2,1621 ]. Diagnostic scoring systems — Several scoring systems have been proposed to standardize the correlation of clinical and laboratory variables. The Alvarado score is the most widely used diagnostic aid for the diagnosis of appendicitis and has been modified slightly since it was introduced [22,23 ]. However, clinical judgment remains paramount. For example, a low modified Alvarado score (<4) is less sensitive than clinical judgement. In a prospective study of 261 adult patients with clinically suspicious appendicitis, in whom 53 patients (20 percent) had a final diagnosis of appendicitis, the low modified Alvarado score was less sensitive compared with unstructured clinical ® ® Children less than 3 years of age (see "Acute appendicitis in children: Clinical manifestations and diagnosis" ) ● Adults older than age 60 years (see "Management of acute appendicitis in adults", section on 'Elderly patients' ) ● Women in the second and third trimesters of pregnancy, due to the displacement of the appendix by the uterus and the resulting changes in the physical examination (see "Acute appendicitis in pregnancy" ) ●