Adult Guidelines
Acute Appendicitis

Acute Appendicitis

Definitions

Without known or suspected perforation or abscess

May include suspected or confirmed abscess, perforation, peritonitis, or gangrenous appendicitis

Empiric Treatment: Acute, Uncomplicated Appendicitis

Empiric Treatment: Acute, Complicated Appendicitis

High risk

  • ≥ 2 of the following:
    • Age ≥ 70 years
    • Major compromise of cardiovascular, liver, or renal function
    • Immunosuppression

Severe (≥ 1 of the following)

  • Severe sepsis or septic shock and/or
  • Diffuse and generalized peritonitis

Hospital-acquired/healthcare-associated (≥ 1 of the following)

  • Infection occurred ≥ 48 hours after admission
  • Infection developing ≥ 48 hours after initial source control
  • Hospitalization ≥ 48 hours in past 90 days WITH receipt of broad-spectrum parenteral antimicrobial therapy

Step Down

Utilize culture results whenever available

Diagnosis

  • Abdominal pain
  • Anorexia
  • Nausea/vomiting
  • Low-grade fever
  • Mild leukocytosis

Longer duration of symptoms and extremes of age increase risk for complicated appendicitis

  • Obtain contrast-enhanced computed tomography (CT) scan of abdomen and pelvis for diagnosis and complications
  • Consider oral and IV contrast if longer duration of symptoms or concern for complications
  • Consider ultrasound for pediatric and pregnant patients or when CT is not readily available
  • Only for severe illness: Obtain blood cultures

Additional Information

August 1, 2023

  1. Montravers P, Tubach F, Lescot T, et al. Short-course antibiotic therapy for critically ill patients treated for postoperative intra-abdominal infection: the DURAPOP randomised clinical trial. Intensive Care Med. 2018 Mar;44(3):300-310.
  2. Sawyer RG, Claridge JA, Nathens AB, et al. Trial of short-course antimicrobial therapy for intraabdominal infection. N Engl J Med. 2015 May 21;372(21):1996-2005. PMID: 25992746
  3. Mazuski JE, Tessier JM, May AK, Sawyer RG, Nadler EP, Rosengart MR, Chang PK, O'Neill PJ, Mollen KP, Huston JM, Diaz JJ Jr, Prince JM. The Surgical Infection Society Revised Guidelines on the Management of Intra-Abdominal Infection. Surg Infect (Larchmt). 2017 Jan;18(1):1-76. doi: 10.1089/sur.2016.261.
  4. Salminen P,Tuominen R, Paajanen H et al. Five year follow-up of antibiotic therapy for uncomplicated acute appendicitis in the APPAC Randomized Clinical Trial. JAMA. 2018. 320(12): 1259-65.
  5. The CODA Collaborative. Randomized trial comparing antibiotics with appendectomy for appendicitis. NEJM. 2020. 383(20): 1907-19.
  6. Van Rossem CC, Schreinemacher MHF, van Geloven AA, et al. Antibiotic duration after laparoscopic appendectomy for acute complicated appendicitis. JAMA Surgery. 2016. 151(4): 323-39.