Gastrointestinal (GI) System


Acute inflammation of the appendix.



  • First described by Reginald Fitz on his paper to the first meeting of the Association of American Physicians in 1886 entitled, ‘Perforating inflammation of the vermiform appendix
  • Charles McBurney described clinical manifestation of acute appendicitis including point of maximum tenderness in right iliac fossa.


Risk Factors:

  • Western-type diet
    • ↓ Dietary fibres
    • ↑ Refined carbohydrates

Non-obstructive causes:

  • Bacterial proliferation (aerobic + anaerobic)

Obstructive causes:

  • Faecolith/Appendicolith (adults) (M/C cause): Inspissated faecal material + calcium phosphates + bacteria + epithelial debris + (rarely) foreign material
  • Tumour:
    • Primarily carcinoma caecum
    • Lymphoid hyperplasia (children)
  • Intestinal parasites: Oxyuris vermicularis (pinworm)



Lymphoid hyperplasia

Luminal hyperplasia

↑ Intraluminal pressure

Lymphatic drainage obstruction

Oedema + mucosal ulceration
Bacterial translocation to the submucosa

2 outcomes:

Resolution or Progression


Venous obstruction + Ischaemia

Bacterial invasion through muscularis propria & submucosa

Ischaemic necrosis of appendix wall

Peritoneal contamination


Walling off of peritoneal contamination by greater omentum & small bowel adherent to the inflamed appendix.


Acute Appendicitis
Acute Appendicitis: An exemplary case of acute appendicitis in a 10-year-old boy. The organ is enlarged and sausage-like (botuliform). This longitudinal section shows red inflamed mucosa with an irregular luminal surface. Diagnosed and removed early in the course of the disease, this appendix does not show late complications, like transmural necrosis, perforation, and abscess formation | By Ed Uthman from Houston, TX, USA – Acute Appendicitis, CC BY 2.0,


  • Diagnostic criteria for acute appendicitis:
    • Presence of neutrophils in smooth muscle layer


  • Periumbilical colic
  • Pain shifting to right iliac fossa
  • Anorexia
  • Nausea


Physical examination:

  • Low-grade pyrexia
  • Localized tenderness in the right iliac fossa
  • McBurney’s point: Point of maximum tenderness located 1⁄3 distance from right anterior superior iliac spine
  • Limitation of respiratory movement
  • Pointing Sign: Patient asked to point where pain began and show its migration (Usually Periumbilical region → right lower abdomen)

Perforation → peritonitis:

  • Muscle guarding
  • Rebound tenderness
  • Psoas sign: Pain on passively extending the thigh of a patient lying on his/her side with knees extended, or asking the patient to flex his thigh at the hip so patient lies with right hip flexed for pain relief
    • Due to inflamed appendix lies on psoas muscle
  • Rovsing’s sign: Deep palpation of left iliac fossa causes pain in right iliac fossa
  • Obturator test/Zachary Cope: Pain in hypogastrium from spasm of obturator internus when right hip is flexed and internally rotated
Obturator sign
Obturator sign: Pain on passive internal rotation of the flexed thigh. Examiner moves lower leg laterally while applying resistance to the lateral side of the knee (asterisk), resulting in internal rotation of the femur. | Illustration by Floyd E. Hosmer | Hardin DM Jr. Acute appendicitis: review and update. Am Fam Physician. 1999;60(7):2030.


Imaging modality of choice in children
  • Filling defect in appendix
  • Appendicular wall thickness ≥ 6 mm
  • Luminal distention, lack of compressibility

CECT abdomen:

Imaging modality of choice in adults

Alvarado score:

Clinical scoring system used in the diagnosis of appendicitis. The score has 6 clinical items and 2 laboratory measurements with a total 10 points.
Alvarado Scoring System (MANTRELS Criteria)
Alvarado Scoring System (MANTRELS Criteria) | Snyder, J., Gurevitz, S., Rush, L.S., McKeague, L.C., & Houpt, C.G. (2013). Acute appendicitis , as shown in an abdominal x-ray , frontal view.

Differential diagnosis:

ChildrenAdultsAdult femaleElderly
GastroenteritisRegional enteritisMittelschmerzDiverticulitis
Mesenteric adenitisUreteric colicPelvic inflammatory diseaseIntestinal obstruction
Meckel’s diverticulitisPerforated peptic ulcerPyelonephritisColonic carcinoma
IntussusceptionTorsion of testesEctopic pregnancyTorsion appendix epiploicae
Henoch–Schönlein Purpura (HSP)PancreatitisTorsion/rupture of ovarian cystMesenteric infarction
Lobar pneumoniaRectus sheath hematomaEndometriosisLeaking aortic aneurysm


Surgical management: Appendectomy

  • Laparoscopic Appendectomy
  • Open procedure
    • Indications:
      • Extensive infection/abscess
      • Perforated appendix
      • Obesity
      • Dense scar tissue from previous surgery
      • Difficulty viewing though laparoscope
      • Bleeding problems
‘Acute appendicitis: Management
Bhangu, A., Søreide, K., Di Saverio, S., Assarsson, J. H. and Drake, F. T. (2017) ‘Acute appendicitis: modern understanding of pathogenesis, diagnosis, and management’, The Lancet. Elsevier, 386(10000), pp. 1278–1287. doi: 10.1016/S0140-6736(15)00275-5.


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