Appendicitis
This page is for adult patients. For pediatric patients, see: appendicitis (peds)
Background
- 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
History
- 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
- Later patient develops abdominal pain
- 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
- Retrocecal appendix can cause flank or pelvic pain
- Gravid uterus sometimes displaces appendix superiorly → RUQ pain
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
- Appendicitis
- Perforated appendicitis
- Peritonitis
- Abdominal aortic aneurysm
- Crohn's disease (terminal ileitis)
- Diverticulitis (cecal, Asian patients)
- Ectopic
- Endometriosis
- Epiploic appendagitis
- Herpes zoster
- Inguinal hernia
- Ischemic colitis
- Kidney stone
- Meckel's diverticulum
- Mesenteric lymphadenitis
- Mesenteric ischemia
- Mittelschmerz
- Neutropenic enterocolitis (typhlitis)
- Ovarian cyst
- Ovarian torsion
- PID
- Pyelonephritis
- Psoas abscess
- Testicular torsion
Evaluation

Labs
- CBC
- Normal WBC does not rule-out appendicitis
- Only 80% of patients will have leukocytosis with left shift[2]
- Urine pregnancy
- Urinalysis
- Leukocytes will be present in 40% of patients[3]
- Serum Lactate
- Does not necessarily define level of severity (if appendicitis is present.)
- Can aid in trending effective resuscitation once the diagnosis is made.
- CRP
- Normal CRP AND WBC makes appendicitis unlikely
Imaging
- 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
- Ultrasound
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).
Management
Supportive Management
- NPO status
- Fluid resuscitation
- Analgesia/antiemetics
Antibiotics
Coverage should extend to E. coli, Klebsiella, Proteus, and Bacteroides (an anaerobe)
Adult Simple Appendicitis
Antibiotic prophylaxis should be coordinated with surgical consult
Options:
- Cefoxitin 2g IV q6 hours OR
- Cefotetan 2g IV q12 hours OR
- Moxifloxacin 400mg IV once daily OR
- Ertapenem 1g IV once daily
Pediatric Simple Appendicitis
Options:
- Cefoxitin 40mg/kg IV q6 hours
- Cefotetan 40mg/kg IV q12 hours
- Gentamicin 2.5mg/kg IV q8hrs +
- Metronidazole 7.5mg/kg IV 16hrs OR
- Clindamycin 10mg/kg IV q8hrs
Complicated Appendicitis
Defined as perforation, abscess, or phlegmon
Options:
- Metronidazole 500 mg IV q8hrs +
- Cefepime 50 mg/kg IV q12hrs OR
- Ciprofloxacin 400 mg IV q12hrs OR
- Levofloxacin 750 mg IV q24hrs OR
- Aztreonam 30 mg/kg IV q8hrs
- Imipenem/Cilastatin 25 mg/kg IV q6hrs (max 500mg)
- Meropenem 20 mg/kg IV q8hrs (max 1g)
- Piperacillin/Tazobactam 100 mg/kg (max 4.5g) IV q8hrs
Cautious use should be applied to use of fluoroquinolones in complicated pediatric appendicitis due to the risk of tendon injury
Surgery
- 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
Disposition
- Admission to surgery team
Complications
Infection
- 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
- CHOP Appendicitis Pathway
- ACEP Clinical Policy Statement
- emDocs - Appendicitis: Why Do We Miss It, and How Do We Improve?
References
- ↑ http://www.thepocusatlas.com/pediatrics/
- ↑ 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.
- ↑ 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
- ↑ Hendahewa R. et al. The dilemma of stump appendicitis - a case report and literature review. Int J Surg Case Rep. 2015; 14: 101-3.
- ↑ Boardman T. et al. Recurrent appendicitis caused by a retained appendiceal tip: A case report. The Journal of Emergency Medicine. 2019; 57: 232-4.