Acute appendicitis in adults: Diagnostic evaluation
- Ronald F Martin, MD
Ronald F Martin, MD
- Clinical Adjunct Professor of Surgery
- University of Wisconsin School of Medicine and Public Health
- Stella K Kang, MD, MS
Stella K Kang, MD, MS
- Assistant Professor of Radiology and Population Health
- NYU School of Medicine
- Section Editor
- Martin Weiser, MD
Martin Weiser, MD
- Section Editor — Colorectal Surgery
- Attending Surgeon
- Memorial Sloan Kettering Cancer Center
- Professor of Surgery
- Weill Cornell Medical School
Appendicitis is common and is seen in up to 1 in 10 individuals over a lifetime. Most cases present between the ages of 10 and 30 years. There is a slight male predominance among patients presenting before age 30 (male:female ratio approximately 3:2). (See "Acute appendicitis in adults: Clinical manifestations and differential diagnosis", section on 'Epidemiology'.)
This topic reviews the diagnostic evaluation of suspected appendicitis in nonpregnant adults, incorporating the clinical evaluation, laboratory tests, and imaging exams. Diagnosis of appendicitis in children and pregnant women is discussed separately, as are the pathogenesis, clinical manifestations, differential diagnosis, and management. (See "Acute appendicitis in children: Clinical manifestations and diagnosis" and "Acute appendicitis in pregnancy" and "Acute appendicitis in adults: Clinical manifestations and differential diagnosis" and "Management of acute appendicitis in adults".)
The evaluation of patients with suspected appendicitis is driven by the goal of identifying all patients presenting with acute appendicitis as early in their clinical course as possible while minimizing the nontherapeutic laparoscopy/laparotomy rate. Missed diagnosis of appendicitis, especially when perforated, can result in severely adverse patient outcomes, while nontherapeutic operations incur surgical morbidity without treating the underlying condition.
The Alvarado score (table 1) uses data from the history, physical exam, and laboratory testing to describe the clinical likelihood of acute appendicitis. Those with a low Alvarado score are triaged for evaluation of alternative diagnoses. In those with a higher Alvarado score, imaging and surgical laparoscopic exploration are used to improve the specificity of evaluation and to minimize the likelihood of a negative laparotomy (algorithm 1).
The evaluation for appendicitis in nonpregnant adults can be particularly challenging in several populations, including:
- Colson M, Skinner KA, Dunnington G. High negative appendectomy rates are no longer acceptable. Am J Surg 1997; 174:723.
- Ege G, Akman H, Sahin A, et al. Diagnostic value of unenhanced helical CT in adult patients with suspected acute appendicitis. Br J Radiol 2002; 75:721.
- Lu Y, Friedlander S, Lee SL. Negative Appendectomy: Clinical and Economic Implications. Am Surg 2016; 82:1018.
- Wagner PL, Eachempati SR, Soe K, et al. Defining the current negative appendectomy rate: for whom is preoperative computed tomography making an impact? Surgery 2008; 144:276.
- Rao PM, Rhea JT, Rattner DW, et al. Introduction of appendiceal CT: impact on negative appendectomy and appendiceal perforation rates. Ann Surg 1999; 229:344.
- Horton MD, Counter SF, Florence MG, Hart MJ. A prospective trial of computed tomography and ultrasonography for diagnosing appendicitis in the atypical patient. Am J Surg 2000; 179:379.
- Güller U, Rosella L, McCall J, et al. Negative appendicectomy and perforation rates in patients undergoing laparoscopic surgery for suspected appendicitis. Br J Surg 2011; 98:589.
- Coursey CA, Nelson RC, Patel MB, et al. Making the diagnosis of acute appendicitis: do more preoperative CT scans mean fewer negative appendectomies? A 10-year study. Radiology 2010; 254:460.
- Drake FT, Florence MG, Johnson MG, et al. Progress in the diagnosis of appendicitis: a report from Washington State's Surgical Care and Outcomes Assessment Program. Ann Surg 2012; 256:586.
- Flum DR, McClure TD, Morris A, Koepsell T. Misdiagnosis of appendicitis and the use of diagnostic imaging. J Am Coll Surg 2005; 201:933.
- Flum DR, Morris A, Koepsell T, Dellinger EP. Has misdiagnosis of appendicitis decreased over time? A population-based analysis. JAMA 2001; 286:1748.
- Jones K, Peña AA, Dunn EL, et al. Are negative appendectomies still acceptable? Am J Surg 2004; 188:748.
- Wilson EB. Surgical evaluation of appendicitis in the new era of radiographic imaging. Semin Ultrasound CT MR 2003; 24:65.
- Parks NA, Schroeppel TJ. Update on imaging for acute appendicitis. Surg Clin North Am 2011; 91:141.
- Barrett ML, Hines AL, Andrews RM. Trends in rates of perforated appendix, 2001–2010: Statistical brief #159. Healthcare Cost and Utilization Project (HCUP) Statistical Briefs [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US). 2006-2013.
- Horattas MC, Guyton DP, Wu D. A reappraisal of appendicitis in the elderly. Am J Surg 1990; 160:291.
- Drake FT, Mottey NE, Farrokhi ET, et al. Time to appendectomy and risk of perforation in acute appendicitis. JAMA Surg 2014; 149:837.
- Kosloske AM, Love CL, Rohrer JE, et al. The diagnosis of appendicitis in children: outcomes of a strategy based on pediatric surgical evaluation. Pediatrics 2004; 113:29.
- Morris KT, Kavanagh M, Hansen P, et al. The rational use of computed tomography scans in the diagnosis of appendicitis. Am J Surg 2002; 183:547.
- Liu CC, Lu CL, Yen DH, et al. Diagnosis of appendicitis in the ED: comparison of surgical and nonsurgical residents. Am J Emerg Med 2001; 19:109.
- Denizbasi A, Unluer EE. The role of the emergency medicine resident using the Alvarado score in the diagnosis of acute appendicitis compared with the general surgery resident. Eur J Emerg Med 2003; 10:296.
- Kharbanda AB, Fishman SJ, Bachur RG. Comparison of pediatric emergency physicians' and surgeons' evaluation and diagnosis of appendicitis. Acad Emerg Med 2008; 15:119.
- Yen K, Karpas A, Pinkerton HJ, Gorelick MH. Interexaminer reliability in physical examination of pediatric patients with abdominal pain. Arch Pediatr Adolesc Med 2005; 159:373.
- Andersson RE. Meta-analysis of the clinical and laboratory diagnosis of appendicitis. Br J Surg 2004; 91:28.
- Bundy DG, Byerley JS, Liles EA, et al. Does this child have appendicitis? JAMA 2007; 298:438.
- Dahabreh IJ, Adam GP, Halladay CW, et al. Diagnosis of right lower quadrant pain and suspected acute appendicitis [Internet]. AHRQ Comparative Effectiveness Reviews 2015; Report No: 15(16)-EHC025-EF.
- Dayawansa NH, Segan JD, Yao HH, et al. Incidence of normal white cell count and C-reactive protein in adults with acute appendicitis. ANZ J Surg 2016.
- Atema JJ, Gans SL, Beenen LF, et al. Accuracy of White Blood Cell Count and C-reactive Protein Levels Related to Duration of Symptoms in Patients Suspected of Acute Appendicitis. Acad Emerg Med 2015; 22:1015.
- Sand M, Bechara FG, Holland-Letz T, et al. Diagnostic value of hyperbilirubinemia as a predictive factor for appendiceal perforation in acute appendicitis. Am J Surg 2009; 198:193.
- Horzić M, Salamon A, Kopljar M, et al. Analysis of scores in diagnosis of acute appendicitis in women. Coll Antropol 2005; 29:133.
- Ohmann C, Franke C, Yang Q. Clinical benefit of a diagnostic score for appendicitis: results of a prospective interventional study. German Study Group of Acute Abdominal Pain. Arch Surg 1999; 134:993.
- Enochsson L, Gudbjartsson T, Hellberg A, et al. The Fenyö-Lindberg scoring system for appendicitis increases positive predictive value in fertile women--a prospective study in 455 patients randomized to either laparoscopic or open appendectomy. Surg Endosc 2004; 18:1509.
- Alvarado A. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med 1986; 15:557.
- Kalan M, Talbot D, Cunliffe WJ, Rich AJ. Evaluation of the modified Alvarado score in the diagnosis of acute appendicitis: a prospective study. Ann R Coll Surg Engl 1994; 76:418.
- Ohle R, O'Reilly F, O'Brien KK, et al. The Alvarado score for predicting acute appendicitis: a systematic review. BMC Med 2011; 9:139.
- Ebell MH, Shinholser J. What are the most clinically useful cutoffs for the Alvarado and Pediatric Appendicitis Scores? A systematic review. Ann Emerg Med 2014; 64:365.
- Tan WJ, Acharyya S, Goh YC, et al. Prospective comparison of the Alvarado score and CT scan in the evaluation of suspected appendicitis: a proposed algorithm to guide CT use. J Am Coll Surg 2015; 220:218.
- Smith MP, Katz DS, Lalani T, et al. ACR Appropriateness Criteria® Right Lower Quadrant Pain--Suspected Appendicitis. Ultrasound Q 2015; 31:85.
- Yun SJ, Ryu CW, Choi NY, et al. Comparison of Low- and Standard-Dose CT for the Diagnosis of Acute Appendicitis: A Meta-Analysis. AJR Am J Roentgenol 2017; 208:W198.
- The LOCAT Group, Kim HJ, Jeon BG, et al. Low-dose CT for the diagnosis of appendicitis in adolescents and young adults (LOCAT): a pragmatic, multicentre, randomised controlled non-inferiority trial. Lancet Gastroenterol Hepatol 2017.
- American College of Radiology (ACR) Committee on Drugs and Contrast Media. ACR manual on contrast media, version 10.1, 2015. Available at: http://www.acr.org/~/media/37D84428BF1D4E1B9A3A2918DA9E27A3.pdf (Accessed on August 17, 2016).
- Dearing DD, Recabaren JA, Alexander M. Can computed tomography scan be performed effectively in the diagnosis of acute appendicitis without the added morbidity of rectal contrast? Am Surg 2008; 74:917.
- Hershko DD, Awad N, Fischer D, et al. Focused helical CT using rectal contrast material only as the preferred technique for the diagnosis of suspected acute appendicitis: a prospective, randomized, controlled study comparing three different techniques. Dis Colon Rectum 2007; 50:1223.
- Pickhardt PJ, Lawrence EM, Pooler BD, Bruce RJ. Diagnostic performance of multidetector computed tomography for suspected acute appendicitis. Ann Intern Med 2011; 154:789.
- Rao PM, Rhea JT, Novelline RA. Sensitivity and specificity of the individual CT signs of appendicitis: experience with 200 helical appendiceal CT examinations. J Comput Assist Tomogr 1997; 21:686.
- Whitley S, Sookur P, McLean A, Power N. The appendix on CT. Clin Radiol 2009; 64:190.
- Choi D, Park H, Lee YR, et al. The most useful findings for diagnosing acute appendicitis on contrast-enhanced helical CT. Acta Radiol 2003; 44:574.
- Benjaminov O, Atri M, Hamilton P, Rappaport D. Frequency of visualization and thickness of normal appendix at nonenhanced helical CT. Radiology 2002; 225:400.
- Nikolaidis P, Hwang CM, Miller FH, Papanicolaou N. The nonvisualized appendix: incidence of acute appendicitis when secondary inflammatory changes are absent. AJR Am J Roentgenol 2004; 183:889.
- Johnson PT, Horton KM, Kawamoto S, et al. MDCT for suspected appendicitis: effect of reconstruction section thickness on diagnostic accuracy, rate of appendiceal visualization, and reader confidence using axial images. AJR Am J Roentgenol 2009; 192:893.
- Yabunaka K, Katsuda T, Sanada S, Fukutomi T. Sonographic appearance of the normal appendix in adults. J Ultrasound Med 2007; 26:37.
- Williams R, Shaw J. Ultrasound scanning in the diagnosis of acute appendicitis in pregnancy. Emerg Med J 2007; 24:359.
- Birnbaum BA, Wilson SR. Appendicitis at the millennium. Radiology 2000; 215:337.
- Kessler N, Cyteval C, Gallix B, et al. Appendicitis: evaluation of sensitivity, specificity, and predictive values of US, Doppler US, and laboratory findings. Radiology 2004; 230:472.
- Jeffrey RB Jr, Laing FC, Townsend RR. Acute appendicitis: sonographic criteria based on 250 cases. Radiology 1988; 167:327.
- Keyzer C, Zalcman M, De Maertelaer V, et al. Comparison of US and unenhanced multi-detector row CT in patients suspected of having acute appendicitis. Radiology 2005; 236:527.
- Kaewlai R, Lertlumsakulsub W, Srichareon P. Body mass index, pain score and Alvarado score are useful predictors of appendix visualization at ultrasound in adults. Ultrasound Med Biol 2015; 41:1605.
- Rosen MP, Ding A, Blake MA, et al. ACR Appropriateness Criteria® right lower quadrant pain--suspected appendicitis. J Am Coll Radiol 2011; 8:749.
- Barger RL Jr, Nandalur KR. Diagnostic performance of magnetic resonance imaging in the detection of appendicitis in adults: a meta-analysis. Acad Radiol 2010; 17:1211.
- Nikolaidis P, Hammond N, Marko J, et al. Incidence of visualization of the normal appendix on different MRI sequences. Emerg Radiol 2006; 12:223.
- GENERAL APPROACH
- Negative appendectomy rate (nontherapeutic operative rate)
- INITIAL EVALUATION
- Clinical evaluation
- Laboratory tests
- Alvarado score calculation
- Selection of modality
- Computed tomography
- Magnetic resonance imaging
- Plain radiography
- SURGICAL EXPLORATION