2. Acute Appendicitis

Acute Appendicitis

Date: 03/2026 | Supersedes: 11/2025 | Location: LBJ General Hospital

Purpose: To standardize management of acute appendicitis at LBJ General Hospital

Patient Population: Patients suspected to have acute appendicitis

Definitions:

  • Simple appendicitis: Appendiceal inflammation without perforation (includes gangrenous appendicitis)
  • Perforated appendicitis:
    • Imaging diagnosis based on extraluminal air or peri-appendiceal abscess.
    • Intraoperative diagnosis based on the presence of at least 1 of 4 possible criteria:
      • Peri-appendiceal abscess
      • Intraoperative visualization of defect in appendiceal wall
      • Intraperitoneal stool or fecalith
      • Pus/fibrinous exudate in any quadrant other than the right lower quadrant

Pediatric Patients:

  • Patients ≥16 years can undergo surgery and be admitted to LBJ
  • Patients <16 years should be transferred if appendicitis is diagnosed

Workup for Suspected Acute Appendicitis:

  • Labs:
    • CBC
    • BMP or CMP
    • Qualitative beta HCG in patients with childbearing potential
    • Urinalysis if urinary symptoms are present
  • Imaging:
    • Non-pregnant adult patients: CT abdomen/pelvis with IV contrast is diagnostic test of choice1
    • Pregnant patients and children: abdominal ultrasound or MRI may be obtained2
      • CT abdomen/pelvis with IV contrast should be obtained in pregnant patients with equivocal ultrasound/MRI results who may have acute appendicitis

 Initial Appendicitis Management:

  • Ceftriaxone and metronidazole should be initiated within 1 hour of appendicitis diagnosis (levofloxacin and metronidazole if penicillin allergy)
    • Note: if diagnosis is uncertain, consult surgery before starting antibiotics
  • NPO order
  • General Surgery consultation

Non-perforated Appendicitis:

  • Determine treatment strategy:
    • Discuss risks/benefits of surgery versus nonoperative management (NOM) with patient
    • Special populations:
      • In general, appendectomy should be recommended to pregnant patients2
      • Consider recommending surgery in older patients2 or immunosuppressed patients
      • Consider recommending NOM in patients with temporary/modifiable risk factors for surgical complications (e.g., recent PCI on DAPT)
    • Operative management of non-perforated appendicitis:
      • Surgery should be performed within 24 hours (ideally <12 hours) of presentation3
        • Post for URGENT laparoscopic appendectomy
      • Patient should void preoperatively, no Foley in OR
      • Include .PATOS in op note to document findings accurately
    • NOM of non-perforated appendicitis:
      • Admit for minimum of 12 hours observation
      • Give 1 dose IV ceftriaxone and metronidazole, then schedule oral Augmentin (levofloxacin/metronidazole if penicillin allergy)
      • Discharge with antibiotic prescription once the following criteria are met:
        • Afebrile with normal heart rate
        • Tolerating regular diet and oral antibiotics without nausea/vomiting
        • Abdominal pain improved/resolved
      • Patients who do not meet discharge criteria may continue inpatient NOM or undergo surgery
    • Antibiotics duration:
      • Operative management: stop antibiotics immediately postoperatively
      • Nonoperative management: complete 7 total days of Augmentin (levofloxacin/metronidazole if penicillin allergy)

 Perforated Appendicitis:

  • Determine treatment strategy:
    • In general, operative management of perforated appendicitis is associated with shorter length of stay, earlier return to work, and increased patient satisfaction2,4,5
    • Surgery should be strongly considered in the following settings:
      • Symptom duration <72 hours6
      • Abscess not amenable to IR drainage
      • Free fecalith within peritoneal cavity or abscess (will not resolve with drain)
    • NOM may be preferred in the following settings:
      • Symptom duration >72 hours6
      • Significant cecal inflammation on CT
      • Well-formed abscess that is amenable to IR drainage (although this is not a contraindication to surgery2,5)
    • Pregnant patients need source control via appendectomy or abscess drainage
      • Pregnant patients with abscesses not amenable to percutaneous drainage should undergo appendectomy or surgical drain placement
    • Operative management of perforated appendicitis:
      • Surgery should be performed as soon as possible
        • Post for URGENT laparoscopic appendectomy
      • Patient should void preoperatively, no Foley in OR unless specified by attending
      • Include .PATOS in op note to document findings accurately
    • Drain placement for perforated appendicitis with abscess:
      • Consult IR for drain placement
        • Surgery chief resident or attending call IR faculty directly
        • Procedure to be completed within 24 hours (including weekends)
        • Faculty-to-faculty discussion is required if drainage will be delayed
      • Antibiotics duration:
        • After source control (surgery/drain): complete 4-day course2,7
          • Transition to PO Augmentin when tolerating diet (levofloxacin/metronidazole if penicillin allergy)
          • If patient not progressing as expected, see “Concern for Postoperative Intra-abdominal Abscess” below
        • NOM without source control (antibiotics only): complete 7-day course, then repeat imaging to assess for drainable collection
          • Transition to PO Augmentin when tolerating diet (levofloxacin/metronidazole if penicillin allergy)

Concern for Postoperative Intra-abdominal Abscess (IAA):

  • Patients with these signs/symptoms may have an IAA:
    • Fever
    • Tachycardia
    • Leukocytosis (particularly with neutrophil predominance)
    • Increasing or persistent abdominal pain
    • PO intolerance or anorexia
    • Ileus
    • Diarrhea
    • Dysuria without UTI
  • Diagnosis: Imaging should be obtained on/after POD4
    • Adult patients: CT abdomen/pelvis with IV and oral contrast
    • Pediatric patients: Ultrasound (first-line), with CT reserved for inconclusive cases
  • Confirmed IAA:
    • Size/location amenable to drainage:
      • Consult IR for drain placement
        • Surgery chief resident or attending call IR faculty directly
        • Procedure to be completed within 24 hours (including weekends)
        • Faculty-to-faculty discussion is required if drainage will be delayed
      • Size/location not amenable to drainage:
        • Complete additional 7-day course of antibiotics after IAA diagnosis, then repeat imaging to assess for resolution versus drainable collection
          • Patient may be discharged during this interval if they meet criteria

Discharge and Follow-Up:

  • Discharge criteria:
    • Afebrile with normal heart rate
    • Pain well controlled with oral medications
    • Tolerating a diet without nausea/vomiting
      • Non-perforated appendicitis patients only need to tolerate a liquid diet
      • Perforated appendicitis patients should tolerate a regular diet
    • Follow-up:
      • Non-perforated: 2-3 weeks after discharge, via telemedicine if straight-forward patient
        • Note: patients do not require interval appendectomy after NOM of simple appendicitis2
          • Patients with persistent symptoms after NOM should get repeat imaging
        • Perforated: 7-14 days after discharge, in person
          • Additional considerations after NOM in perforated appendicitis:
            • Colonoscopy should be obtained in patients ≥40 years
            • Perforated appendicitis WITH abscess:
              • Patients ≥35 years: recommend interval appendectomy due to 14% rate of underlying malignancy8
              • Patients <35 years: discuss risks/benefits of interval appendectomy
            • Perforated appendicitis WITHOUT abscess:
              • Discuss risks/benefits of interval appendectomy (2% rate of underlying malignancy in absence of abscess)8

References:

  1. Kambadakone, A. R. et al. ACR Appropriateness Criteria® Right Lower Quadrant Pain: 2022 Update. Journal of the American College of Radiology 19, S445–S461 (2022).
  2. Podda, M. et al. Diagnosis and Treatment of Acute Appendicitis: 2025 Edition of the World Society of Emergency Surgery Jerusalem Guidelines. JAMA Surg. https://doi.org/10.1001/jamasurg.2025.6218 (2026) doi:10.1001/jamasurg.2025.6218.
  3. Di Saverio, S. et al. Diagnosis and treatment of acute appendicitis: 2020 update of the WSES Jerusalem guidelines. World Journal of Emergency Surgery vol. 15 Preprint at https://doi.org/10.1186/s13017-020-00306-3 (2020).
  4. Schurman, J. V., Cushing, C. C., Garey, C. L., Laituri, C. A. & St. Peter, S. D. Quality of life assessment between laparoscopic appendectomy at presentation and interval appendectomy for perforated appendicitis with abscess: analysis of a prospective randomized trial. J. Pediatr. Surg. 46, 1121–1125 (2011).
  5. Mentula, P., Sammalkorpi, H. & Leppäniemi, A. Laparoscopic Surgery or Conservative Treatment for Appendiceal Abscess in Adults? A Randomized Controlled Trial. Ann. Surg. 262, 237–242 (2015).
  6. Jiang, L. et al. Does the time from symptom onset to surgery affect the outcomes of patients with acute appendicitis? A prospective cohort study of 255 patients. Asian J. Endosc. Surg. 14, 361–367 (2021).
  7. Sawyer, R. G. et al. Trial of Short-Course Antimicrobial Therapy for Intraabdominal Infection. New England Journal of Medicine 372, 1996–2005 (2015).
  8. Salminen, R. et al. Appendiceal Tumor Prevalence in Patients With Periappendicular Abscess Invited Commentary Supplemental content including those for text and data mining, AI training, and similar technologies. https://doi.org/10.1001/jamasurg.2025.0312 (2025) doi:10.1001/jamasurg.2025.0312.