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Study guide:


  • inflammation of the appendix.



  • It is the most common cause of acute abdomen requiring surgery, affecting 7% of the US population.

  • The peak incidence for appendicitis is 10-30 years old.

Mortality rate is 0.1% in non-perforated cases. 



  • Obstruction of the appendiceal lumen is the main trigger of appendicitis and it usually happens due to:

    • Fecalith in adult.

    • Lymphoid hyperplasia in pediatrics.

  • After obstruction the luminal pressure will rise with the excessive mucus secretion, exceeding the capillary venous and lymphatic pressure, leading to venous infarction.

  • Bacterial overgrowth → inflammation.


Clinical Presentation:

  • Periumbilical pain then shifts to be localized to the RLQ.

    • In perforated appendicitis →Peritonitis

      • If it was walled-off (contained) by adjacent organs →localized pain.

      • If it was not walled-off (common in infants) → diffused abdominal pain.

  • Anorexia.

  • Nausea and vomiting (after the pain).

  • Low-grade fever (not more than 38 C, unless perforated).

  • Rebound tenderness, and guarding of the abdominal muscles (suggesting peritonitis).

  •  Males may experience pain in the right, left, or both testicles (innervated by T10).

Initial periumbilical pain occurs due to visceral pain (which follows the embryological origin, midgut).

Valinteno sign: a sign for duodenal ulcer perforation but with the same presentation of appendicitis (Plain film with air under diaphragm in AXR). 


  • Mainly CLINICAL

  • CBC: might show mild leukocytosis with left shift. 

  • Ultrasound is to rule out any gynecological pathology in females, and to confirm the diagnosis in patients with atypical presentation.  

  • CT scan with contrast in selective patients with atypical presentation, and more sensitive and specific than ultrasound. 


  • Appendectomy is the only treatment for appendicitis except in cases of perforation.

    • Laparoscopy vs. laparotomy.

  • Preoperative antibiotics are essential (Cefuroxime +metronidazole).  

  • Specific situations:

  • If you opened the patient and you found the appendix to be normal:

    • If open appendectomy → take out the appendix even if you find another pathology (e.g.: Meckel’s diverticulum, ovarian cyst etc.)

      • For the incision not confuse any subsequent surgeon decision if he presented with something similar later.

      • Do not take it out if the patient is known to have inflammatory bowel disease (risk of fistula formation).

    • If laparoscopic appendectomy → after exploring the abdomen:

      • If there is NO pathology, remove the appendix.

      • If there is another pathology, DO NOT remove the appendix. 


  • Perforation:

    • Especially in elderly and pediatric age groups.

    • Usually associated with severe diffuse pain after it was localized.

    • Uncommon to happen within the first 24 hours (usually after 72 hours).

    • Worsening symptoms, high fever, and sepsis.

  • Peritonitis:

    • Occurs as a consequence of perforation.

  • Abscess formation:

    • Might be felt as a RLQ mass on physical examination.

    • CT scan or ultrasound guided percutaneous drainage should be performed first with antibiotics treatment.

    • After 6-8 weeks, the patient should undergo appendectomy (interval appendectomy).

Appendicitis & Pregnancy:

  • It is the most common extra-uterine surgical emergency in pregnant females. 

  • It occurs with the same frequency and incidence in both pregnant and non-pregnant females.

  • It usually occurs during the first two trimesters.

  • The location of the appendix is changed:

    • It is in its normal position until 12 weeks of gestation.

    • After 12 weeks of gestation, it is displaced upward and laterally.

    • At 20 weeks of gestation, it reaches the umbilicus.

    • And by the 24th week, it reaches to the iliac crest.

  • Laparoscopy is as safe as laparotomy.

  • Early surgical intervention is essential to prevent fetal mortality, which can reach up to 25%. 

  • The risk of premature delivery is greatest during the first week post-op. 

Differential diagnoses: 

  • Mickel’s diverticulitis.

  • Inflammatory bowel disease.

  • Hernia encarceration.

  • Renal or ureter stones.  

  • OB/GYN: ectopic pregnancy, PID, … 

If digital rectal exam shows puffiness in the rectum think of appendicular abscess.

In young adults and pediatric, do lymph node examination to check for mesenteric lymphadenitis which may resemble the symptoms of appendicitis.



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  • Le T, Krause K. First aid for the basic sciences. New York: McGraw-Hill Medical; 2012.

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  • Blackbourne L. Surgical recall. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins; 2009.

  • Agabegi S, Agabegi E, Ring A. Step-up to medicine. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins; 2013.

  • Kaufman M, Stead L, Stead S. First aid for the surgery clerkship. New York: McGraw-Hill Medical; 2009.

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Written by:     Roaa Amer     

Reviewed by:    Haifa Al Issa 
                          Lama Al Luhidan

Format Editor:  Bassam AlGhamdi 

Web Publisher:  Adel Yasky

                           Bayan Alzomaili

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