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:
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- 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