A practical guide to appendicitis evaluation and treatment
Which clinical findings most reliably point to appendicitis? How do the 3 primary clinical scoring systems compare? When is it time to order imaging studies?
PRACTICE RECOMMENDATIONS
› Use the Alvarado Score, Pediatric Appendicitis Score, or Appendicitis Inflammatory Response Score to help rule out appendicitis and thereby reduce unnecessary imaging. A
› Choose ultrasound first as the imaging procedure for children and pregnant women, followed by magnetic resonance imaging if needed, to reduce ionizing radiation in these populations. B
› Consider an antibiotic-based strategy under the care of a surgeon in lieu of immediate surgery for uncomplicated appendicitis. A
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Complicated appendicitis
Excluding patients with severe sepsis or purulent peritonitis requiring resuscitation and immediate surgical intervention of intra-abdominal infection, the approach to patients with complicated appendicitis varies between aggressive surgical intervention and nonoperative management.
In a 2007 meta-analysis reviewing nonsurgical treatment of appendiceal abscess/phlegmon, immediate surgery was associated with higher morbidity.24 Within the nonoperative management group 7.2% (CI, 4.0-10.5) required surgical intervention and 19.7% (CI, 11.0-28.3) required abscess drainage. Malignant disease was detected in 1.2% (CI, 0.6-1.7).24 Small subsequent studies concluded different results.25
Ultimately, the 2015 European Association of Endoscopic Surgery guidelines recommend a new systematic review; but with current data, initial nonoperative management is preferred.15 After initial nonoperative treatment, the only benefits from interval appendectomy are identification of an underlying malignancy (6% to 20%) and mitigating the risk of recurrent appendicitis (5% to 44%).15,25-30
Multiple single institutional series found increased neoplasm incidence (9% to 20%) in complicated appendicitis in patients 40 years and older.26-30 Prior to interval appendectomy in patients 45 years and older, ensuring they have an up-to-date screening colonoscopy is important. This is in line with 2021 US Preventive Services Task Force (Grade “B” recommendation), 2018 American Cancer Society (qualified recommendation), and 2021 American College of Gastroenterology (conditional recommendation) guidelines for colorectal cancer screening to start at age 45 in average-risk patients.31 Patients younger than 45 can consider screening through shared decision-making.
Special populations
Pregnant patients
In pregnancy, challenges exist with the presence of traditional signs and symptoms of appendicitis, with the most predictive sign being a WBC count higher than 18,000.32 The American College of Radiology’s (ACR) Appropriateness Criteria recommend US as the imaging modality of choice in pregnancy, with MRI as the best option when US is inconclusive.33 Two meta-analyses demonstrated high sensitivity (91.8%-96.6%) and specificity (95.9%-97.9%) of MRI in diagnosing appendicitis.34,35 CT scan is not the preferred initial imagining modality in pregnancy unless urgent information is needed and other modalities are insufficient or unavailable.36
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