(Redirected from Acute appendicitis)

This page is for adult patients. For pediatric patients, see: appendicitis (peds)


Drawing of colon with variability of appendix locations as seen from anterior view.
  • Acute inflammation of the vermiform appendix
  • Most common non-obstetric surgical emergency in pregnancy
  • Most common abdominal surgical emergency in patients <50
  • Most common between 10-30 years, but no age is exempt
  • Most commonly caused by luminal obstruction by a fecalith
  • There are no historical or physical exam findings that can definitively rule out appendicitis

Clinical Features

Location of McBurney's point (1), located two thirds the distance from the umbilicus (2) to the right anterior superior iliac spine (3).


  • Early on primarily malaise, indigestion, anorexia
    • Later patient develops abdominal pain
      • Initially vague, periumbilical (visceral innervation)
      • Later migrates to McBurney point (parietal innervation)
      • <50% of patients have this typical presentation
  • Nausea, with or with out emesis, typically follows onset of pain
  • Fever may or not occur
  • Urinary symptoms common given proximity of appendix to urinary tract (sterile pyuria)
  • Sudden improvement suggests perforation
  • 33% of patients have atypical presentation

Physical Exam

  • McBurney's: maximal tenderness to palpation 2/3 of the way between umbilicus and right anterior superior iliac spine
  • Rovsing sign (palpation of LLQ worsens RLQ pain)
  • Psoas sign (extension of right leg at hip while patient lies on left side elicits abdominal pain)
  • Obturator sign (internal and external rotation of thigh at hip elicits pain
  • Peritonitis suggested by:
    • Right heel strike elicits pain
    • Guarding
    • Rebound
    • Rigidity

Clinical Examination Operating Characteristics

Procedure LR+ LR-
RLQ pain 7.3-8.4 0-0.28
Rigidity 3.76 0.82
Migration 3.18 0.50
Pain before vomiting 2.76 NA
Psoas sign 2.38 0.90
Fever 1.94 0.58
Rebound 1.1-6.3 0-0.86
Guarding 1.65-1.78 0-0.54
No similar pain previously 1.5 0.32
Anorexia 1.27 0.64
Nausea 0.69-1.2 0.70-0.84
Vomiting 0.92 1.12

Differential Diagnosis

RLQ Pain


Dilated, non-compressible appendix with appendicolith and surrounding free fluid[1]
Peri-appendiceal fat stranding in the setting of acute appendicitis.
Fecalith (arrow) and stranding in the setting of acute appendicitis.
Dialated appendix and stranding in the setting of acute appendicitis.

Appendicitis Risk Scores

Alvarado Clinical Scoring System

Right Lower Quadrant Tenderness +2
Elevated Temperature (37.3°C or 99.1°F) +1
Rebound Tenderness +1
Migration of Pain to the Right Lower Quadrant +1
Anorexia +1
Nausea or Vomiting +1
Leukocytosis > 10,000 +2
Leukocyte Left Shift +1

Clinical scoring system, where a score (Total=10) is composed on presence/absence of 3 signs, 3 symptoms and 2 lab values to help guide in case management.

  • ≤3 = Appendicitis unlikely
  • ≥7 = Surgical consultation
  • 4-6 = Consider CT

MANTRELS Mnemonic: Migration to the right iliac fossa, Anorexia, Nausea/Vomiting, Tenderness in the right iliac fossa, Rebound pain, Elevated temperature (fever), Leukocytosis, and Shift of leukocytes to the left (factors listed in the same order as presented above).


  • Abdominal panel
    • CBC
      • Normal WBC does not rule-out appendicitis
      • Only 80% of patients will have leukocytosis with left shift[2]
    • Chemistry
    • Consider LFTs + lipase
    • Consider coagulation studies (PT, PTT, INR), as a marker of liver function
  • Urine pregnancy
  • Urinalysis
    • Leukocytes will be present in 40% of patients[3]
  • Consider serum lactate
    • Does not necessarily define level of severity (if appendicitis is present.)
    • Can aid in trending effective resuscitation once the diagnosis is made.
  • Consider CRP
    • Normal CRP AND WBC makes appendicitis unlikely


  • Early surgical consultation should be obtained before imaging in straightforward cases
  • Not universally necessary; consider in:
    • Women of reproductive age
    • Men with equivocal presentation
  • Perforation may result in false negative study
  • Imaging modalities
    • Ultrasound
      • First choice for pregnant women and children
      • Limitations: operator-dependent, difficult to visualize with obesity, gravid uterus, bowel gas, guarding, lack of patient cooperation
      • Findings: noncompressible appendix >6mm in diameter, wall thickness greater or equal to 3 mm
      • Other supportive findings: aperistalsis, distinct wall layers, target appearance in axial view, appendicolith, periappendiceal fluid, prominent echogenic periappendiceal fat
    • CT
      • First choice for adult males and nonpregnant women with equivocal cases
      • Women derive the greatest benefit from preoperative imaging (lower neg appy rate)
      • Contrast (both PO and IV) is unnecessary but typically ordered
    • MRI
      • When unable to identify appendix in children or pregnant women


Supportive Management

  1. NPO status
  2. Fluid resuscitation
  3. Analgesia/antiemetics


Coverage should extend to E. coli, Klebsiella, Proteus, and Bacteroides (an anaerobe)

Adult Simple Appendicitis

Antibiotic prophylaxis should be coordinated with surgical consult


Pediatric Simple Appendicitis


Complicated Appendicitis

Defined as perforation, abscess, or phlegmon


Cautious use should be applied to use of fluoroquinolones in complicated pediatric appendicitis due to the risk of tendon injury


  • Open laparotomy or laparoscopy
    • Patients who present <72 hours after the onset of symptoms usually undergo immediate appendectomy
    • Patients who present >72hrs and have perforated appendix may be treated initially with antibiotics, intravenous fluids, and bowel rest


  • Admission



  • Either a simple wound infection or an intraabdominal abscess
    • Typically in patients with perforated appendicitis

Recurrent appendicitis

  • Occurs in approximately 1:50,000 appendectomies [4]
  • Typically caused by inflammation of the remaining appendiceal stump
    • Can also be caused by a retained piece of the appendix not removed during surgery [5]
  • Can present similar to primary appendicitis
  • Treatment similar to that of primary appendicitis and likely requires surgical revision of the appendiceal stump or removal of retained tissue
  • Delay in diagnosis and treatment can result in perforation and sepsis

See Also

External Links


  2. Khan MN, Davie E, Irshad K. The role of white cell count and C-reactive protein in the diagnosis of acute appendicitis. J Ayub Med Coll Abbottabad. 2004;16(3):17-19.
  3. Baird DLH, Simillis C, Kontovounisios C, Rasheed S, Tekkis PP. Acute appendicitis. BMJ. 2017;357:j1703. Published 2017 Apr 19. doi:10.1136/bmj.j1703
  4. Hendahewa R. et al. The dilemma of stump appendicitis - a case report and literature review. Int J Surg Case Rep. 2015; 14: 101-3.
  5. Boardman T. et al. Recurrent appendicitis caused by a retained appendiceal tip: A case report. The Journal of Emergency Medicine. 2019; 57: 232-4.