II. Epidemiology

  1. Lifetime Incidence
    1. Women: 6.7%
    2. Men: 8.6%

III. Pathophysiology

  1. Appendix is long, thin diverticulum
    1. Arises from inferior cecum
  2. Appendicitis course
    1. Luminal obstruction
    2. Mucosal Ulceration
    3. Bacterial Infection
  3. Appendix Perforation
    1. Perforation Course
      1. Pus spills into peritoneal cavity
      2. Results in peritonitis
      3. Abscess forms
    2. Perforation at time of surgery increases with age
      1. Young patients: 20%
      2. Elderly: 70%

IV. Risk Factors

  1. Decreased Dietary Fiber (high Dietary Fiber protective)
  2. Ingestion of refined carbohydrates
  3. Infection
    1. Viral epidemic
    2. Amebiasis outbreak
    3. Bacterial Gastroenteritis

V. Precautions

  1. Extremes of age yield atypical presentations
    1. McBurney's Point pain occurs in only 33% of children
    2. Newborns may present only irritable or lethargic
  2. Observe carefully men with Abdominal Pain

VI. Symptoms

  1. Anorexia (low predictive value)
    1. Likelihood Ratio: 1.1
    2. Test Sensitivity: 84%
    3. Test Specificity: 66%
  2. Nausea
    1. Test Sensitivity: 58-68%
    2. Test Specificity: 40%
  3. Vomiting
    1. Test Sensitivity: 50%
    2. Test Specificity: 45-69%
  4. Abdominal Pain (occurs in virtually all cases)
    1. Predictive value of findings
      1. Right lower quadrant pain (Most important history finding)
        1. Likelihood Ratio: 8.4
        2. Test Sensitivity: 81-96%
        3. Test Specificity: 53%
      2. Pain occurs before Vomiting
        1. Test Sensitivity: 100%
        2. Test Specificity: 64%
      3. Pain migration from Periumbilical Pain to Right Lower Quadrant Abdominal Pain
        1. Likelihood Ratio: 3.6
    2. Course of pain (Classic): Occurs in 50% of cases
      1. Initial: Crampy Periumbilical Pain for 12-24 hours
      2. Later: Steady, sharp RLQ Abdominal Pain
      3. Provocative: Cough or Movement

VII. Signs

  1. Typical Presentation
    1. Low grade fever (38.3 - 39.4 C)
      1. Test Sensitivity: 67%
      2. Test Specificity: 69%
      3. Often absent in elderly
    2. Involuntary abdominal guarding or rigidity
      1. Likelihood Ratio: 1.59
      2. Test Sensitivity: 21-74%
      3. Test Specificity: 57-84%
    3. Rebound Abdominal Tenderness
      1. Likelihood Ratio: 2.03 (RLQ Abdominal Pain when LLQ pressure is released)
      2. Test Sensitivity: 26-63%
      3. Test Specificity: 69%
    4. Point tenderness in right lower quadrant (RLQ)
      1. See McBurney's Point
    5. RLQ tenderness on pelvic exam or rectal exam
  2. Perforated Appendix
    1. Accentuated pain
    2. Vomiting
    3. Higher fever and Leukocytosis
    4. Tender RLQ mass
      1. Suggests Appendiceal abscess
      2. Also seen with Phlegmon (Cecum inflammation)
  3. Extrapelvic Appendix
    1. Right back muscle inflammed (tender below 12th rib)
    2. Psoas and Illiopsoas inflammation
      1. Patient keeps right thigh flexed or rigid extension
      2. Iliopsoas Test (Psoas Sign)
        1. Test Sensitivity: 16%
        2. Test Specificity: 95%
    3. Right Ureter Inflammation (Dysuria or Pyuria)
  4. Intrapelvic Appendix
    1. Diffuse Suprapubic Pain
    2. No abdominal muscle rigidity
    3. Bladder irritation (Dysuria)
    4. Rectum irritation (tenesmus)
    5. Obturator internus inflammation
      1. Obturator Test
    6. Palpable tender mass on rectal exam
  5. Additional exam signs
    1. Rovsing's Sign
      1. Right Lower Quadrant Abdominal Pain occurs on palpation of the left lower quadrant
    2. Psoas Sign
      1. Patient in the left lateral decubitus position
      2. Right lower quadrant pain with hyperextension of the the right hip
    3. Obturator Sign (Obturator Test)
      1. Right lower quadrant pain on internal rotation of the flexed right thigh
    4. Dunphy's Sign
      1. Increased pain with cough

VIII. Lab

  1. Precautions
    1. No lab marker has sufficient Test Sensitivity to exclude Appendicitis
    2. Al-Abed (2014) Am J Surg S0002-9610(14): 00360-2 [PubMed]
  2. Complete Blood Count: Neutrophilic Leukocytosis
    1. Poor predictive value (poor sensitivity and Specificity)
      1. Leukocytes normal in 25% of Appendicitis cases
    2. High Negative Predictive Value
      1. In children, Likelihood Ratio with WBC <10,000 is 0.22
    3. Interpretation
      1. Leukocytes range: 10,000 to 20,000 (in 75% of Appendicitis cases)
      2. Leukocytosis over 15,000 compels evaluation
      3. Higher Leukocytosis suggests appendix perforation
  3. C-Reactive Protein (C-RP)
    1. Increases within 6-12 hours
    2. Test Sensitivity for Appendicitis: 76%
      1. Test Sensitivity improves if C-RP remains normal despite >24 hours of symptoms
      2. In some studies, normal C-RP at 24 hours had a nearly 100% Negative Predictive Value
  4. Urinalysis
    1. Sterile pyuria can occur if appendix is adjacent to ureter
    2. Do not exclude Appendicitis based on urine alone unless urine findings are definitive

X. Diagnosis

  1. Alvarado Score (MANTRELS Score)
    1. Unreliable - not recommended (misses almost a third of Appendicitis cases)
  2. Pediatric Appendicitis Score
    1. Unreliable alone, but better efficacy when combined with Appendix Ultrasound (see Pediatric Appendicitis Pathway)
  3. No further testing if Appendicitis diagnosis is clear
    1. Based on history and examination

XI. Imaging

  1. CT Abdomen with contrast (preferred in most cases)
    1. See CT Abdomen in Appendicitis
  2. RLQ Abdominal Ultrasound
    1. See Ultrasound in Appendicitis
    2. If appendix is not visualized, or high clinical suspicion despite negative Ultrasound
      1. Perform other imaging or perform close interval serial examinations
  3. MRI Abdomen (consider in children)
    1. Eliminates the ionizing radiation risk of CT Abdomen
    2. However, longer study (10 min) and may require Sedation in children
    3. Test Sensitivity and Test Specificity: 97-100% each
    4. Kearl (2016) Acad Emerg Med 23(2): 179-85 [PubMed]

XII. Management: Helmer study protocol

  1. Acute Suppurative Appendicitis
    1. Cefotetan 25 mg/kg IV preoperatively (or similar agent such as Imipenem)
    2. Appendectomy
  2. Appendicitis with Abscess
    1. Initial antibiotics as in perforated Appendicitis
      1. Continue antibiotics until no fever or Leukocytosis
    2. Percutaneous drainage
      1. Drain left in place
      2. Remove drain when cathetergram normal
    3. Appendectomy follows drainage
  3. Perforated Appendicitis
    1. Initial antibiotics
      1. Gentamicin 7 mg/kg IV or Levofloxacin 500 mg IV and
      2. Metronidazole 500 mg IV q6 hours
    2. Appendectomy
      1. Non-perforated: No additional Management
      2. Perforated or gangrenous appendix
        1. Appendectomy wound left open
        2. Continue antibiotics for 7 days
        3. If fever, Leukocytosis, or obstipation persist
          1. Obtain CT Abdomen and Pelvis
          2. Abscess present
            1. Percutaneous drainage
            2. Base antibiotics on Gram Stain and culture
          3. No abscess
            1. Consider imipenem 500 mg IV q6 hours
  4. References
    1. Helmer (2002) Am J Surg 183:609 [PubMed]

XIII. Management: Other Regimens

  1. Appendicitis in Pregnancy (1 case per 1500 births)
    1. Site of surgical incision is controversial
    2. Transverse incision at McBurney's Point recommended
    3. Popkin (2002) Am J Surg 183:20-2 [PubMed]
  2. Antibiotic only treatment
    1. Augmentin for 4 days
    2. Appendectomy ultimately needed in only 7-12% of cases at 7-30 days and in 12-30% in the next year
    3. Higher risk of peritonitis (8% versus 2%)
      1. However limiting antibiotic only strategy to appendix diameter <10mm might reduce that risk
    4. References
      1. Park (2014) Int J Surg 12(9): 897-900 [PubMed]
      2. Vous (2011) Lancet 377(9777):1573-9 [PubMed]

XIV. Precautions

  1. Initial missed diagnosis approaches 50% (especially at extremes of age)
    1. Often complicated by appendix perforation
  2. Observation protocol in a stable patient when diagnosis is unclear
    1. Outpatient with return for recheck in 12 hours for responsible patients (and parents of pediatric patients)
    2. Inpatient observation is recommended when follow-up cannot be assured
  3. Imaging
    1. Ultrasound lean pediatric patients first if your ultrasonographers and radiologists are experienced with Appendix Ultrasound
    2. CT Abdomen should be obtained if indicated and other modalities are non-diagnostic (despite radiation risk)
      1. Risk of missed appendix outweighs risk of radiation exposure when clinical suspicion dictates
  4. Documentation
    1. Clearly document history, examination, patient stability and decision making
      1. Explain abnormal findings (including labs)
    2. More likely alternative diagnoses should be explained and fit classic diagnostic criteria
      1. Example: Gastroenteritis should primarily be Vomiting and Diarrhea without focal tenderness
  5. References
    1. Claudius and Kassinove in Majoewsky (2012) EM:RAP 12(10): 2-3

XV. Prognosis

  1. Mortality overall
    1. Nonperforated: <1%
    2. Perforated: 5%
  2. Mortality if age over 75 years: 25%

XVI. References

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Ontology: Appendicitis (C0003615)

Definition (MEDLINEPLUS)

The appendix is a small, tube-like organ attached to the first part of the large intestine. It is located in the lower right part of the abdomen. It has no known function. A blockage inside of the appendix causes appendicitis. The blockage leads to increased pressure, problems with blood flow, and inflammation. If the blockage is not treated, the appendix can burst and spread infection into the abdomen. This causes a condition called peritonitis.

The main symptom is pain in the abdomen, often on the right side. It is usually sudden and gets worse over time. Other symptoms may include

  • Swelling in the abdomen
  • Loss of appetite
  • Nausea and vomiting
  • Constipation or diarrhea
  • Inability to pass gas
  • Low fever

Not everyone with appendicitis has all these symptoms.

Appendicitis is a medical emergency. Treatment almost always involves removing the appendix. Anyone can get appendicitis, but it is more common among people 10 and 30 years old.

National Institute of Diabetes and Digestive and Kidney Diseases

Definition (MSHCZE) Zánět červovitého přívěsku (appendixu), zánět „slepého střeva“. Nejčastější zánětlivá náhlá příhoda břišní. Akutní a. se projevuje celkovou nevolností a bolestí břicha. Ta je v typických případech nejprve neurčitá kolem pupku, později se stěhuje do pravého podbřišku a stává se ostrou a bodavou. Dochází k dráždění pobřišnice a při proděravění appendixu k jejímu zánětu (peritonitidě) s celkově těžkým stavem. U malých dětí, těhotných a u netypicky uloženého appendixu může být průběh odlišný. U žen je někdy třeba odlišit zánět vaječníků (adnexitidu), který může drážděním z appendixu i vznikat. Akutní a. se nejčastěji léčí operativním odstraněním červovitého přívěsku – appendektomií, některé případy se řeší nejprve konzervativně (ledové obklady, dieta, popř. antibiotika). Chronická a. probíhá méně bouřlivě s opakovanými bolestmi břicha. Příznaky nejsou zcela typické, proto je někdy nutné vyloučit jiná onemocnění. Je-li diagnóza potvrzena, volí se obv. operace. (cit. Velký lékařský slovník online, 2013 http://lekarske.slovniky.cz/ )
Definition (MSH) Acute inflammation of the APPENDIX. Acute appendicitis is classified as simple, gangrenous, or perforated.
Concepts Disease or Syndrome (T047)
MSH D001064
ICD9 541, 540-543.99
ICD10 K37
SnomedCT 196785005, 155733005, 307530000, 155736002, 155729003, 155728006, 74400008
English Appendicitis, unqualified, Unspecified appendicitis, appendicitis (diagnosis), appendicitis, Unqualified appendicitis, Appendicitis NOS, Appendicitis, Appendicitis [Disease/Finding], Appendicitis, unqualified (disorder), Appendicitis NOS (disorder), Appendicitis (disorder), inflammation; appendix, appendix; inflammation, Appendicitis, NOS, APPENDICITIS
French APPENDICITE, Appendicite non précisée, Appendicite, non précisée, Appendicite
Portuguese APENDICITE, Apendicite não qualificada, Apendicite
Dutch appendicitis, niet-gekwalificeerd, niet-gekwalificeerde appendicitis, appendix; ontsteking, ontsteking; appendix, Appendicitis, niet gespecificeerd, appendicitis, Appendicitis
German unqualifizierte Appendizitis, Appendizitis, unqualifiziert, Wurmfortsatzentzündung, Blinddarmentzündung, Nicht naeher bezeichnete Appendizitis, Appendizitis
Italian Appendicite, non precisata, Appendicite non definita, Appendicite
Spanish Apendicitis no calificada, apendicitis, SAI (trastorno), apendicitis, SAI, apendicitis, no calificada, Appendicitis NOS, apendicitis, no calificada (trastorno), apendicitis (trastorno), apendicitis, inflamación aguda del apéndice, Apendicitis
Japanese 性質不明の虫垂炎, セイシツフメイノチュウスイエン, チュウスイエン, 虫垂炎, 虫様突起炎
Swedish Blindtarmsinflammation
Czech appendicitida, zánět slepého střeva, apendicitida, Blíže neurčená apendicitida, Apendicitida, Apendicitida, blíže neurčená
Finnish Umpilisäketulehdus
Russian APPENDITSIT, АППЕНДИЦИТ
Korean 상세불명의 충수염
Croatian APENDICITIS
Polish Zapalenie wyrostka robaczkowego
Hungarian Appendicitis, nem minősített, Nem minősített appendicitis, appendicitis
Norwegian Blindtarmbetennelse, Appendisitt