• Clinical science
  • Clinician

Acute appendicitis


Acute appendicitis is the acute inflammation of the appendix, typically due to an obstruction of the appendiceal lumen. It is the most common cause of acute abdomen requiring emergency surgical intervention in both children and adults. The characteristic features of acute appendicitis are periumbilical abdominal pain that migrates to the right lower quadrant (RLQ), anorexia, nausea, fever, and RLQ tenderness. When seen alongside neutrophilic leukocytosis, these features are sufficient to make a clinical diagnosis using appendicitis scoring systems to estimate the likelihood of appendicitis. Imaging (e.g., abdominal CT with IV contrast, abdominal ultrasonography) may be considered if the clinical diagnosis is uncertain. The current standard of management of acute appendicitis is emergency appendectomy (laparoscopic or open) and antibiotics. Nonoperative management (NOM), which includes bowel rest, antibiotics, and analgesics, is indicated in patients with an inflammatory appendiceal mass (phlegmon) or an appendiceal abscess, because surgical intervention is associated with a higher risk of complications in these patient groups. Interval appendectomy 6–8 weeks following resolution of the acute episode may be considered in these patients to prevent a recurrence or if there is concern for an underlying appendiceal tumor.



  • Common cause of acute abdomen [2]
  • Lifetime risk: ∼ 8%
  • Peak incidence: 10–19 years of age [3]
  • Sex: >


Epidemiological data refers to the US, unless otherwise specified.


Caused by obstruction of the appendiceal lumen due to: [4]

  • Lymphoid tissue hyperplasia; (60% of cases): most common cause in children and young adults
  • Fecalith; and fecal stasis (35% of cases): most common cause in adult
  • Neoplasm; (uncommon): more likely in patients > 50 years of age [5]
  • Parasitic infestation (uncommon): e.g., Enterobius vermicularis, Ascaris lumbricoides, and species of the Taenia and Schistosoma genera [6]



  • Obstructed proximal appendiceal lumen (closed-loop obstruction), resulting in: [8]
    • Stasis of mucosal secretions bacterial multiplication and local inflammation transmural spread of infection → clinical features of appendicitis
    • Increased intraluminal pressure → obstruction of veins edema of the appendiceal walls → obstruction of capillaries ischemia → gangrenous appendicitis with/without perforation
  • Inflammation can spread to serosa, leading to peritonitis


Clinical features

The location of the pain may be variable as the appendix's location varies, especially in pregnant women. [11]



The initial approach to management should be guided by the likelihood of acute appendicitis based on clinical features and laboratory parameters (see Risk stratification tools for acute appendicitis).


Acute appendicitis is usually a clinical diagnosis based on history, physical examination, and laboratory studies. The appendicitis scoring systems should be used to guide management decisions. Imaging is recommended if the clinical diagnosis is uncertain.

Laboratory studies [11][16]

  • Routine studies
    • CBC: mild leukocytosis with left shift ; normal WBC count does not rule out acute appendicitis
    • CRP: elevated (> 10 mg/L) [16]
    • BMP: ↑ creatinine, electrolyte abnormalities may be present in patients with severe vomiting; and diarrhea
    • Urinalysis: typically normal in appendicitis; possible findings of mild pyuria and/or hematuria
  • Tests to rule out differential diagnoses

Risk stratification tools for acute appendicitis

There are several scoring systems to estimate the likelihood of acute appendicitis in a patient with RLQ pain. The following three scoring systems are most frequently used in clinical practice and are based on clinical features and laboratory studies. These scores guide management decisions, including determining when imaging may be unnecessary.

Alvarado score (MANTRELS) [11][13][17][18][19]

  • A 10-point scoring system that uses eight parameters to estimate the likelihood of appendicitis
  • Leukocytosis and RLQ tenderness carry the greatest weight.
  • Accuracy is higher in young to middle-aged adults than in children < 10 years of age and adults > 60 years of age. [16] [18]
Alvarado score (MANTRELS) [20]
Characteristics Score
Symptoms Migration of pain to RLQ 1
Anorexia 1
Nausea and/or vomiting 1
Physical examination Tenderness in RLQ 2
Rebound pain 1
Elevated temperature > 37.3°C (99.1°F) 1
Laboratory parameters Leukocytosis (> 10,000/mm3) 2
Shift to the left (≥ 75% neutrophils) 1
Likelihood of appendicitis
  • ≤ 4: Low [17]
  • 5–6: Moderate
  • ≥ 7: High [17]

The Alvarado score may not provide a reliable estimated likelihood of acute appendicitis in patients who are either very young or very old. [16]

Pediatric appendicitis score [21][22]

  • A scoring system to estimate the likelihood of appendicitis in patients 3–18 years of age
  • The parameters that carry the greatest scores are RLQ tenderness and RLQ pain elicited on coughing, jumping, and percussion.
Pediatric appendicitis score [21]
Characteristics Score
Symptoms Migration of pain to RLQ 1
Anorexia 1
Nausea/vomiting 1
Physical examination RLQ tenderness 2
RLQ pain elicited on coughing/jumping/percussion 2
Temperature ≥ 38°C (100.4°F) 1
Laboratory parameters Leukocytosis (≥ 10,000/mm3) 1
PMN ≥ 75% 1

Likelihood of appendicitis [23]

  • ≤ 3: Low
  • 4–6: Moderate
  • ≥ 7: High

Appendicitis inflammatory response score [11]

  • A relatively new scoring system that places emphasis on laboratory parameters and the gradation of clinical features to provide a more objective clinical evaluation
  • Provides a more accurate estimated likelihood of acute appendicitis than the Alvarado scoring system [24]
Appendicitis inflammatory response score [25]
Characteristics Score
Symptoms Vomiting 1
RLQ pain 1
Physical examination Rebound tenderness Mild 1
Moderate 2
Strong 3
Temperature ≥ 38.5°C (101.3°F) 1
Laboratory parameters Leukocytosis 10,000/mm3–14,999/mm3 1
≥ 15,000/mm3 2
PMN 70–84% 1
≥ 85% 2
CRP 10–49 mg/L 1
≥ 50 mg/L 2
Likelihood of appendicitis
  • ≤ 4: Low
  • 5–8: Moderate
  • ≥ 9: High

Imaging [11][16][12][26][27]

The risks and benefits of imaging in patients with suspected appendicitis must be carefully weighed. Appendicitis scoring systems can be used to guide imaging decisions. [17][16]

  • Recommended indications [16][13][17][23][27]
    • Moderate likelihood of appendicitis
    • Patients > 60 years of age, regardless of the likelihood scores [13][28]
    • To rule out suspected differential diagnoses
  • Relative indications [17]
  • Imaging likely unnecessary [17]

CT abdomen with IV contrast

  • Indications: preferred initial imaging modality in adults (except for pregnant women) [26]
  • Supportive findings [26]
    • Distended appendix (diameter > 6 mm)
    • Edematous appendix with periappendiceal fat stranding
    • Possible appendiceal fecalith: focal hyperdensity within the appendiceal lumen
    • Evidence of complications
  • Additional considerations
    • Consider low-dose CT scan (with IV contrast) to minimize radiation exposure. [29]
    • Consider CT without contrast in patients with contrast allergy.

Abdominal ultrasound

  • Indications
    • Preferred initial imaging modality in children or pregnant patients [26]
    • An alternative to CT scan if ultrasound findings are inconclusive [27]
  • Supportive findings [16] [30]

Abdominal ultrasound is more reliable for confirming acute appendicitis than ruling it out. [16]

MRI abdomen and pelvis [13][26][31]

  • Indications
    • MRI without IV contrast: pregnant patients with inconclusive ultrasound findings [26][31]
    • MRI with IV contrast: nonpregnant patients with inconclusive ultrasound findings and contraindications for CT scan
  • Findings: similar to CT scan findings

Diagnostic laparoscopy


Supportive care

Antibiotic therapy [12][27][34][35]

  • Indication: all patients with acute appendicitis
  • Required coverage: : against gram-negative and anaerobic organisms [12]

Empiric antibiotic therapy for acute appendicitis [12][35]

Parameters to consider Recommended antibiotic regimens Duration
Uncomplicated appendicitis Managed with appendectomy [12][13][35]
  • Discontinue after surgery or within 24 hours [12][13]
Non-operative management (NOM) [12][36][31]
  • Not yet standardized
  • Initial parenteral antibiotics for at least 2–3 days then switch to oral antibiotics for 7 days.
  • See ''Nonoperative management'' below for further details. [36][31]

Complicated appendicitis

(managed with appendectomy or NOM) [37][38][13][31]

  • 3–5 days [37][38][13][31]

Operative management with appendectomy [12][13][27][39][31]

Appendectomy in patients with an appendiceal abscess or an inflammatory appendiceal mass is associated with an increased risk of intraoperative hemorrhage, postoperative wound infection, and fecal fistula formation. [42]

Nonoperative management of acute appendicitis (NOM; conservative management) [13][36][31][43][44]

Indications [12][36][31][41][44]

Contraindications [36][31]

Early uncomplicated appendicitis

The use of NOM in early uncomplicated appendicitis is an area of ongoing research. [12][36]

  • Advantages: avoids operative risks and costs in approx. 80% of patients [31][44]
  • Disadvantages [36][31][44][47]
    • Approx. 20% chance of recurrence requiring an appendectomy [31]
    • Recurrent need for outpatient visits and antibiotic use
    • Risk of missing an appendiceal tumor
    • Patient anxiety about recurrent episodes [36]

Steps of nonoperative management [12][36]

Think of PAIN to remember the conservative management of appendicitis: Pain management, Antibiotics, Intravenous fluid therapy, NPO!

Interval appendectomy [13][31][44][49][50]

  • Definition: appendectomy performed 6–8 weeks following the resolution of an acute episode of appendiceal mass or appendiceal abscess to minimize surgical complications [50]
  • Indications
    • Currently not routinely recommended [13][44]
    • Consider in persistent or recurrent symptoms of appendicitis in a patient with an appendiceal mass or appendiceal abscess treated conservatively. [13][31][41]
    • Consider in patients > 40 years of age if there is concern for an underlying appendiceal tumor. [51][52]
  • Advantages of routine interval appendectomy
    • Decreased risk of recurrences [31][43][50]
    • Decreased risk of missing an underlying appendiceal tumor [31][52]
    • Decreases need for recurrent outpatient visits
    • Decreases patient anxiety related to potential recurrence [36]
  • Disadvantages of routine interval appendectomy

Acute management checklist

This checklist is applicable to patients with confirmed acute appendicitis and those with a high likelihood of appendicitis according to any of the risk stratification tools for acute appendicitis.


  • The appendix is composed of the same four histological layers of the alimentary canal.
  • See “Microscopic anatomy” in large intestine for the histological features of a healthy appendix.
  • Transmural neutrophilic infiltration is the characteristic histological feature of acute appendicitis.
  • Blood vessel thrombosis, mucosal ulceration, and/or gangrene of the appendiceal wall may also be present.

Differential diagnoses

Right-sided carcinoma of the colon may manifest with clinical features similar to those of acute appendicitis! [55]


The differential diagnoses listed here are not exhaustive.


Inflammatory appendiceal mass (appendiceal phlegmon) [31][41]

Appendiceal abscess [31][41][12]

Gangrenous appendicitis

Perforated appendix [31]

Pylephlebitis [57]

We list the most important complications. The selection is not exhaustive.



Special patient groups

Appendicitis in children [11][58]

  • The reliability of signs and symptoms in children is lower.
    • Most reliable symptoms: emesis and duration of pain
    • Most reliable signs: abdominal tenderness and pain with walking, jumping, or coughing
  • Ultrasound is the diagnostic procedure of choice.

Appendicitis in pregnancy [11][59]

Appendicitis in patients > 60 years of age [13][48][60][28][14]

  • Clinical presentation
  • Older patients are more likely to develop complications, especially perforated appendix. [13]
  • Imaging should be considered regardless of the scores. [13]
  • Consider diagnostic laparoscopy if imaging findings are inconclusive. [13][14]
  • Consider colonoscopy after treatment of acute appendicitis to rule out early colonic malignancy. [48][13]

Patients > 60 years of age have a higher risk of perforation! [13]

  • 1. Salminen P, Paajanen H, Rautio T, et al. Antibiotic Therapy vs Appendectomy for Treatment of Uncomplicated Acute Appendicitis: The APPAC Randomized Clinical Trial. JAMA. 2015; 313(23): pp. 2340–8. doi: 10.1001/jama.2015.6154.
  • 2. Feldman M, Friedman LS, Brandt LJ. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. Philadelphia, PA, USA: Elsevier Saunders; 2016.
  • 3. Martin RF. Acute appendicitis in adults: Clinical manifestations and differential diagnosis. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/acute-appendicitis-in-adults-clinical-manifestations-and-differential-diagnosis#H5346248. Last updated February 5, 2016. Accessed December 12, 2016.
  • 4. Tao Le, Vikas Bhushan, Deol M, Reyes G. First Aid for the USMLE Step 2 CK, Tenth Edition. New York: McGraw-Hill Education; 2018.
  • 5. Lamber LA. Appendiceal Cancer and Tumors. https://rarediseases.org/rare-diseases/appendiceal-cancer-tumors/. Updated January 1, 2018. Accessed June 5, 2019.
  • 6. Altun E, Avci V, Azatçam M. Parasitic infestation in appendicitis. A retrospective analysis of 660 patients and brief literature review. Saudi Med J. 2017; 38(3): pp. 314–318. doi: 10.15537/smj.2017.3.18061.
  • 7. Le T, Bhushan V, Chen V, King M. First Aid for the USMLE Step 2 CK. McGraw-Hill Education; 2015.
  • 8. Agabegi SS, Agabegi ED. Step-Up To Medicine. Baltimore, MD, USA: Wolters Kluwer Health; 2015.
  • 9. Craig S. Appendicitis. In: Brenner BE. Appendicitis. New York, NY: WebMD. http://emedicine.medscape.com/article/773895-treatment. Updated December 27, 2015. Accessed December 14, 2016.
  • 10. Struller F, Weinreich F-J, Horvath P, et al. Peritoneal innervation: embryology and functional anatomy. Pleura and Peritoneum. 2017; 2(4): pp. 153–161. doi: 10.1515/pp-2017-0024.
  • 11. Snyder MJ, Guthrie M, Cagle S. Acute Appendicitis: Efficient Diagnosis and Management. Am Fam Physician. 2018; 98(1): pp. 25–33. pmid: 30215950.
  • 12. Solomkin JS, Mazuski JE, Bradley JS, et al. Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Clin Infect Dis. 2010; 50(2): pp. 133–164. doi: 10.1086/649554.
  • 13. Di Saverio et al. WSES Jerusalem guidelines for diagnosis and treatment of acute appendicitis. World Journal of Emergency Surgery. 2016; 11(1). doi: 10.1186/s13017-016-0090-5.
  • 14. Pryor AD. Diagnostic Laparoscopy for Suspected Appendicitis. Springer New York; 2004: pp. 497–506.
  • 15. Moberg A-C, Ahlberg G, Leijonmarck C-E, et al. Diagnostic laparoscopy in 1043 patients with suspected acute appendicitis. European Journal of Surgery. 2003; 164(11): pp. 833–840. doi: 10.1080/110241598750005246.
  • 16. Howell set al. Clinical Policy: Critical Issues in the Evaluation and Management of Emergency Department Patients With Suspected Appendicitis. Ann Emerg Med. 2010; 55(1): pp. 71–116. doi: 10.1016/j.annemergmed.2009.10.004.
  • 17. Coleman JJ, Carr BW, Rogers T, et al. The Alvarado score should be used to reduce emergency department length of stay and radiation exposure in select patients with abdominal pain. The journal of trauma and acute care surgery. 2018; 84(6): pp. 946–950. doi: 10.1097/TA.0000000000001885.
  • 18. Ohle R, O’Reilly F, O’Brien KK, Fahey T, Dimitrov BD. The Alvarado score for predicting acute appendicitis: a systematic review. BMC Med. 2011; 9(1). doi: 10.1186/1741-7015-9-139.
  • 19. McKay R, Shepherd J. The use of the clinical scoring system by Alvarado in the decision to perform computed tomography for acute appendicitis in the ED. Am J Emerg Med. 2007; 25(5): pp. 489–93. doi: 10.1016/j.ajem.2006.08.020.
  • 20. Alvarado A. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med. 1986; 15(5): pp. 557–64. doi: 10.1016/s0196-0644(86)80993-3.
  • 21. Samuel M. Pediatric appendicitis score. J Pediatr Surg. 2002; 37(6): pp. 877–81. doi: 10.1053/jpsu.2002.32893.
  • 22. Kulik DM, Uleryk EM, Maguire JL. Does this child have appendicitis? A systematic review of clinical prediction rules for children with acute abdominal pain. J Clin Epidemiol. 2013; 66(1): pp. 95–104. doi: 10.1016/j.jclinepi.2012.09.004.
  • 23. 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(4): pp. 365–372.e2. doi: 10.1016/j.annemergmed.2014.02.025.
  • 24. Yeo CJ. Shackelford's Surgery of the Alimentary Tract, E-Book. Elsevier Health Sciences; 2017.
  • 25. Andersson M, Andersson RE. The Appendicitis Inflammatory Response Score: A Tool for the Diagnosis of Acute Appendicitis that Outperforms the Alvarado Score. World J Surg. 2008; 32(8): pp. 1843–1849. doi: 10.1007/s00268-008-9649-y.
  • 26. Garcia EM, Camacho MA, et al. American College of Radiology ACR Appropriateness Criteria® Right Lower Quadrant Pain-Suspected Appendicitis. https://acsearch.acr.org/docs/69357/Narrative/. Updated January 1, 2018. Accessed June 11, 2019.
  • 27. Gorter RR, Eker HH, Gorter-Stam MAW, et al. Diagnosis and management of acute appendicitis. EAES consensus development conference 2015. Surg Endosc. 2016; 30(11): pp. 4668–4690. doi: 10.1007/s00464-016-5245-7.
  • 28. Su Y-J, Lai Y-C, Chen C-C. Atypical Appendicitis in the Elderly. International Journal of Gerontology. 2011; 5(2): pp. 117–119. doi: 10.1016/j.ijge.2011.04.001.
  • 29. Kim K, Kim YH, Kim SY, et al. Low-Dose Abdominal CT for Evaluating Suspected Appendicitis. N Engl J Med. 2012; 366(17): pp. 1596–1605. doi: 10.1056/nejmoa1110734.
  • 30. Mostbeck G, Adam EJ, Nielsen MB, et al. How to diagnose acute appendicitis: ultrasound first. Insights into imaging. 2016; 7(2): pp. 255–63. doi: 10.1007/s13244-016-0469-6.
  • 31. Becker P, Fichtner-Feigl S, Schilling D. Clinical Management of Appendicitis. Visceral Medicine. 2018; 34(6): pp. 453–458. doi: 10.1159/000494883.
  • 32. Gomes CA, Sartelli M, Di Saverio S, et al. Acute appendicitis: proposal of a new comprehensive grading system based on clinical, imaging and laparoscopic findings. World J Emerg Surg. 2015; 10: p. 60. doi: 10.1186/s13017-015-0053-2.
  • 33. Zachariou Z, Scholz S, Waag KL. Diagnostic Laparoscopy in Cases of Suspected Appendicitis: Does the Appendix Have to Be Removed?. Pediatric Endosurgery & Innovative Techniques. 2001; 5(3): pp. 287–293. doi: 10.1089/10926410152634411.
  • 34. Mui LM, Ng CSH, Wong SKH, et al. OPTIMUM DURATION OF PROPHYLACTIC ANTIBIOTICS IN ACUTE NON-PERFORATED APPENDICITIS. ANZ J Surg. 2005; 75(6): pp. 425–428. doi: 10.1111/j.1445-2197.2005.03397.x.
  • 35. Bratzler DW, Dellinger EP, Olsen KM, et al. Clinical practice guidelines for antimicrobial prophylaxis in surgery. Am J Health Syst Pharm. 2013; 70(3): pp. 195–283. doi: 10.2146/ajhp120568.
  • 36. Flum DR. Acute Appendicitis — Appendectomy or the “Antibiotics First” Strategy. N Engl J Med. 2015; 372(20): pp. 1937–1943. doi: 10.1056/nejmcp1215006.
  • 37. van Rossem CC, Schreinemacher MH, van Geloven AA, Bemelman WA, Snapshot Appendicitis Collaborative Study Group. Antibiotic Duration After Laparoscopic Appendectomy for Acute Complicated Appendicitis. JAMA surgery. 2016; 151(4): pp. 323–9. doi: 10.1001/jamasurg.2015.4236.
  • 38. Van den Boom AL, de Wijkerslooth EML, Wijnhoven BPL. Systematic Review and Meta-Analysis of Postoperative Antibiotics for Patients with a Complex Appendicitis. Dig Surg. 2019; 37(2): pp. 101–110. doi: 10.1159/000497482.
  • 39. Seudeal K, Abidi H, Shebrain S. Early versus delayed appendectomy: A comparison of outcomes. The American Journal of Surgery. 2017; 215(3): pp. 483–486. doi: 10.1016/j.amjsurg.2017.10.057.
  • 40. Patel SV, Groome PA, J Merchant S, Lajkosz K, Nanji S, Brogly SB. Timing of surgery and the risk of complications in patients with acute appendicitis: A population-level case-crossover study. The journal of trauma and acute care surgery. 2018; 85(2): pp. 341–347. doi: 10.1097/TA.0000000000001962.
  • 41. Sartelli M, Chichom-Mefire A, Labricciosa FM, et al. The management of intra-abdominal infections from a global perspective: 2017 WSES guidelines for management of intra-abdominal infections. World J Emerg Surg. 2017; 12: p. 29. doi: 10.1186/s13017-017-0141-6.
  • 42. Brown C, Kang L, Kim S. Percutaneous Drainage of Abdominal and Pelvic Abscesses in Children. Seminars in Interventional Radiology. 2012; 29(04): pp. 286–294. doi: 10.1055/s-0032-1330062.
  • 43. 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): p. 1259. doi: 10.1001/jama.2018.13201.
  • 44. Rushing A, Bugaev N, Jones C, et al. Management of acute appendicitis in adults. Journal of Trauma and Acute Care Surgery. 2019; 87(1): pp. 214–224. doi: 10.1097/ta.0000000000002270.
  • 45. Loftus TJ, Dessaigne CG, Croft CA, et al. A protocol for non-operative management of uncomplicated appendicitis. The journal of trauma and acute care surgery. 2018; 84(2): pp. 358–364. doi: 10.1097/TA.0000000000001709.
  • 46. Minneci PC, Sulkowski JP, Nacion KM, et al. Feasibility of a nonoperative management strategy for uncomplicated acute appendicitis in children. J Am Coll Surg. 2014; 219(2): pp. 272–9. doi: 10.1016/j.jamcollsurg.2014.02.031.
  • 47. Di Saverio S, Sibilio A, Giorgini E, et al. The NOTA Study (Non Operative Treatment for Acute Appendicitis): prospective study on the efficacy and safety of antibiotics (amoxicillin and clavulanic acid) for treating patients with right lower quadrant abdominal pain and long-term follow-up of conservatively treated suspected appendicitis. Ann Surg. 2014; 260(1): pp. 109–17. doi: 10.1097/SLA.0000000000000560.
  • 48. Sylthe Pedersen E, Stornes T, Rekstad LC, Martinsen TC. Is there a role for routine colonoscopy in the follow-up after acute appendicitis?. Scand J Gastroenterol. 2018; 53(8): pp. 1008–1012. doi: 10.1080/00365521.2018.1485732.
  • 49. Federico Coccolini, Paola Fugazzola, Massimo Sartelli, et al. Conservative treatment of acute appendicitis. Acta Bio Medica Atenei Parmensis. 2018; 89(9-S): pp. 119–134. doi: 10.23750/abm.v89i9-S.7905.
  • 50. Quartey B. Interval appendectomy in adults: A necessary evil?. Journal of Emergencies, Trauma, and Shock. 2012; 5(3): p. 213. doi: 10.4103/0974-2700.99683.
  • 51. Lu P, McCarty JC, Fields AC, et al. Risk of appendiceal cancer in patients undergoing appendectomy for appendicitis in the era of increasing nonoperative management. J Surg Oncol. 2019; 120(3): pp. 452–459. doi: 10.1002/jso.25608.
  • 52. Mällinen J, Rautio T, Grönroos J, et al. Risk of Appendiceal Neoplasm in Periappendicular Abscess in Patients Treated With Interval Appendectomy vs Follow-up With Magnetic Resonance Imaging: 1-Year Outcomes of the Peri-Appendicitis Acuta Randomized Clinical Trial. JAMA surgery. 2019; 154(3): pp. 200–207. doi: 10.1001/jamasurg.2018.4373.
  • 53. Rushfeldt CF, Sveinbjørnsson B, Søreide K, Vonen B. Risk of anastomotic leakage with use of NSAIDs after gastrointestinal surgery. Int J Colorectal Dis. 2011; 26(12): pp. 1501–1509. doi: 10.1007/s00384-011-1285-6.
  • 54. McMillan JA, Feigin RD, DeAngelis C, Jones MD. Oski's Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins; 2006.
  • 55. Deken MM, de Bie SH, de Noo ME. Acute appendicitis of coloncarcinoom?. Ned Tijdschr Geneeskd. 2016. url: https://www.ntvg.nl/artikelen/acute-appendicitis-coloncarcinoom/extended_abstract.
  • 56. Pinto et al. CT Evaluation of Appendicitis and Its Complications: Imaging Techniques and Key Diagnostic Findings. American Journal of Roentgenology. 2005; 185(2): pp. 406–417. doi: 10.2214/ajr.185.2.01850406.
  • 57. Choudhry AJ, Baghdadi YMK, Amr MA, Alzghari MJ, Jenkins DH, Zielinski MD. Pylephlebitis: a Review of 95 Cases. Journal of Gastrointestinal Surgery. 2015; 20(3): pp. 656–661. doi: 10.1007/s11605-015-2875-3.
  • 58. Kharbanda AB, Stevenson MD, Macias CG, et al. Interrater Reliability of Clinical Findings in Children With Possible Appendicitis. Pediatrics. 2012; 129(4): pp. 695–700. doi: 10.1542/peds.2011-2037.
  • 59. Pastore PA, Loomis DM, Sauret J. Appendicitis in Pregnancy. J Am Board Fam Med. 2006; 19(6): pp. 621–626. doi: 10.3122/jabfm.19.6.621.
  • 60. Dhadlie S, Mehanna D. Rates of colorectal cancer detection in screening colonoscopy post appendicectomy in patients 50 years and over. Annals of Medicine and Surgery. 2018; 36: pp. 239–241. doi: 10.1016/j.amsu.2018.11.012.
  • Willekens et al. The Normal Appendix on CT: Does Size Matter?. PLoS ONE. 2014; 9(5): p. e96476. doi: 10.1371/journal.pone.0096476.
  • Dubrovskaya Y, Tejada R, Bosco J 3rd, et al. Single high dose gentamicin for perioperative prophylaxis in orthopedic surgery: Evaluation of nephrotoxicity. SAGE open medicine. 2015; 3: p. 2050312115612803. doi: 10.1177/2050312115612803.
  • Old JL, Dusing RW, Yap W, Dirks J. Imaging for suspected appendicitis. Am Fam Physician. 2005; 71(1): pp. 71–8. pmid: 15663029.
  • Scott AJ, Mason SE, Arunakirinathan M, Reissis Y, Kinross JM, Smith JJ. Risk stratification by the Appendicitis Inflammatory Response score to guide decision-making in patients with suspected appendicitis. Br J Surg. 2015; 102(5): pp. 563–572. doi: 10.1002/bjs.9773.
  • Demetrashvili Z, Kenchadze G, Pipia I, Ekaladze E, Kamkamidze G. Management of Appendiceal Mass and Abscess. An 11-Year Experience. Int Surg. 2015; 100(6): pp. 1021–1025. doi: 10.9738/intsurg-d-14-00179.1.
  • Tannoury J. Treatment options of inflammatory appendiceal masses in adults. World Journal of Gastroenterology. 2013; 19(25): p. 3942. doi: 10.3748/wjg.v19.i25.3942.
  • Perez K, Allen S. Complicated appendicitis and considerations for interval appendectomy. Journal of the american academy of physician assistance. 2018; 31. url: https://www.deepdyve.com/lp/wolters-kluwer-health/complicated-appendicitis-and-considerations-for-interval-appendectomy-uRzXCPbOLE?articleList=%2Fsearch%3Fquery%3Dinterval%2Bappendectomy.
  • Craig S. Appendicitis Medication. In: Brenner BE. Appendicitis Medication. New York, NY: WebMD. https://emedicine.medscape.com/article/773895-medication#1. Updated June 23, 2018. Accessed June 11, 2019.
  • D'Souza N. Appendicitis. BMJ clinical evidence. 2011; 2011. pmid: 21477397.
  • Sharma and Knipe. Appendix. https://radiopaedia.org/articles/appendix-1?lang=us. Accessed June 4, 2019.
  • Appendix. https://www.histology.leeds.ac.uk/digestive/appendix.php. Accessed June 3, 2019.
  • Addis et al. The epidemiology of appendicitis and appendectomy in the United States. Am J Epidemiol. 1990; 132(5): pp. 910–925. doi: 10.1093/oxfordjournals.aje.a115734.
  • Martin RF, Kang SK. Acute Appendicitis in Adults: Diagnostic Evaluation. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/acute-appendicitis-in-adults-diagnostic-evaluation. Last updated May 30, 2018. Accessed January 13, 2019.
  • Kumar V, Abbas AK, Aster JC. Robbins & Cotran Pathologic Basis of Disease. Philadelphia, PA: Elsevier Saunders; 2015.
  • Abdel-Halim AW. Passing the USMLE: Clinical Knowledge. Springer Science+Business Media; 2009.
  • Smink D, Soybel DI. Management of acute appendicitis in adults. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/management-of-acute-appendicitis-in-adults?source=see_link#H770943. Last updated October 24, 2016. Accessed December 14, 2016.
  • Herold G. Internal Medicine. Cologne, Germany: Herold G; 2014.
  • Talan DA, Saltzman DJ, DeUgarte DA, Moran GJ. Methods of conservative antibiotic treatment of acute uncomplicated appendicitis: A systematic review. The journal of trauma and acute care surgery. 2019; 86(4): pp. 722–736. doi: 10.1097/TA.0000000000002137.
last updated 11/14/2020
{{uncollapseSections(['piaLs4', 'qiaCs4', 'IiaYG4', 'riafG4', 'HiaKG4', 'siatG4', 'Nj1-0S0', 'tm1Xhh0', 'Fm1ghh0', 'ch1a1g0', '8iaOt4', 'uiapt4', 'viaAt4', 'Dia1F4', '9iaNF4'])}}