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Appendicitis: want to learn more about it?

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Appendicitis is an acute inflammation of appendix. This can occur due to a blockage in the appendix lumen by faecolith (mass of hard faeces), or lymphatic hyperplasia, or sometimes even by intestinal worms or parasites including pinworms. The inflammatory process is activated and bacteria within the appendix multiply which is causing the inflammation.

Examples of bacteria seen in the appendix are Escherichia Coli and Bacteroides fragilis. Thrombosis of the capillaries and small veins can occur whilst the arterioles remain open. This can lead to engorgement of the appendix from increased pressure in the lumen due to obstruction. It is a very common surgical emergency and requires urgent care if suspected.

Patients usually experience appendicitis either in their adolescence, or early adulthood or up to their late forties.


The vermiform (worm shaped) appendix develops embryonically from the caecum. It is a closed ended cylinder with the average length of 9 cm and ranges from 2 cm to 20 cm, it is up to 8 mm wide. It is located in the right iliac fossa and 2 cm beneath the ileocecal valve. The ileocaecal valve is a sphincter that separates the large intestine and the small intestine. Its function is to reduce colonic contents refluxing to the ileum. The Mcburney’s point is one-third away from the anterior superior iliac spine (ASIS) to the umbilicus, and this corresponds to the base of the appendix attached to the caecum.

The function of the appendix remains unknown, however some theories say that it acts a storage unit of good flora (bacteria). However, it is widely thought to be a remnant of evolution with no longer any use.

Vermiform appendix (ventral view)

Signs and symptoms

Patients with appendicitis will present with abdominal pain, right lower quadrant pain (right iliac fossa), and anorexia (loss of appetite). The abdominal pain will begin centrally and then localises to the right lower quadrant. Other common symptoms are nausea, vomiting and fever. On examination there can be decreased bowel sounds. Physical examination findings include rebound tenderness, rigidity and guarding.

Signs to elicit specific to Appendicitis:

  1. Rovsing’s sign: On palpation you apply pressure to the left lower quadrant (left iliac fossa) on the abdomen, this will in turn elicit pain in the right lower quadrant (right iliac fossa). This due to bringing the swollen appendix against the peritoneal wall which elicits the irritative painful response. This sign occurs due to referred pain as the pain nerve fibres, which run deep in the gut, do not localise.
  2. Obturator sign: The right hip is internally rotated and flexed which will elicit pain in the right lower quadrant (right iliac fossa) on the abdomen. This is an indicator of irritation of the Obturator internus muscle, if the inflamed appendix is in contact with the muscle.
  3. Psoas sign: To elicit this sign the patient needs to lie in the left lateral position then the right thigh is passively extended and raised which elicits pain in the right lower quadrant (right iliac fossa). A retrocaecal appendix, that is inflamed, will cause irritation to the iliopsoas group of muscles, which are retroperitoneal. The second technique is to ask the supine patient to actively flex their hips, which also elicits the painful stimulus. 


  • Initial investigations if the patient is a woman is to check for pregnancy, this is done with a urinary pregnancy test and should come back negative to rule it out.
  • A full blood count is important to check for infection, mild leucocytosis can be present.
  • For imaging an abdominal and pelvic CT scan should be ordered. An abnormal scan will show an increased diameter of the appendix by >6mm and calcification can be seen.
  • If the history is atypical other investigations to consider are ultrasound of the abdomen. Urinalysis can be checked for differential of renal colic, to rule out red cells, white cells, nitrates would be negative.
  • MRI of the abdomen and pelvic area could be considered in pregnancy. This is an alternative imaging option to CT scan in pregnancy.


  • After diagnosis of appendicitis has been confirmed the patient should be made nil by mouth in preparation for surgery. The patient should then be started on maintenance intravenous fluids.
  • To minimise risk of complications, the surgical option of appendectomy should be performed without delay. Laparoscopic appendectomy can be performed to reduce surgical scarring and a better cosmetic result. Laparoscopic procedures have other benefits for example; reduced postoperative stay in the hospital, reduction is complications, and less postoperative pain.
  • Open appendectomy is considered in pregnant women more often as it is considered to be a safer option for them.


At presentation

  • Unfortunately, complications can occur for example, surgical wound infection, perforation, peritonitis or abscess formation.
  • Generalised peritonitis is a severe complication, which can arise from after a large perforation. Patients present with high fevers, abdominal pain, and absent bowel sounds. This is considered to be an acute abdomen. Laparotomy is the treatment option if this complication occurs.
  • If the disease process progresses without any intervention appendicular abscesses can form. This occurs particularly after perforation. Abscess formation can be seen on ultrasound or CT scan. The treatment for this is intravenous antibiotics and drainage guided by CT.
  • Perforation occurs around after 12 hours the appendix being inflamed. This is why medical and surgical intervention with no delay is vital. Perforated appendicitis would present with severe abdominal pain, tenderness and decreased bowel sounds. In all cases, appendectomy needs to be performed which can be open or laparoscopically.


Surgical wound infection is a postoperative complication, which occurs less so in laparoscopic procedures. Antibiotics can be given prophylactically to prevent this from happening.


  • Appendicitis is inflammation of the appendix.
  • It is one of the most common surgical emergencies.
  • Obstruction in the appendix caused by faecolith can lead to infection.
  • Bacteria seen in the appendix are Escherichia Coli and Bacteroides fragilis.
  • Patients present with abdominal pain, right iliac fossa tenderness and anorexia.
  • Rovsing’s sign, psoas sign and Obturator sign can all be positive in appendicitis.
  • Tests to order are full blood count, urine dip and pregnancy test, abdominal and pelvis CT scan. Test to consider are abdominal ultrasound, urinalysis and abdominal and pelvic MRI.
  • Patients with suspected appendicitis need to be kept nil by mouth and be given maintenance intravenous fluids. Antibiotics can be considered.
  • Treatment is appendectomy.
  • Possible complications: surgical wound infection, abscess formation, perforation or peritonitis.

Appendicitis: want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

What do you prefer to learn with?

“I would honestly say that Kenhub cut my study time in half.” – Read more. Kim Bengochea Kim Bengochea, Regis University, Denver

Show references


  • Murray Longmore, Ian Wilkinson, Andrew Baldwin, Elizabeth Wallin: Oxford Handbook of Clinical Medicine, 9th Edition
  • Appendicitis. WebMD, LLC. (accessed 15/05/2016) 
  • W. H. Bowen: Appendicitis A Clinical Study. Cambridge University Press.
  • A.L Baert, M.F Reiser, H. Hricak, M. Knauth. Edited by Caroline Keyzer, Pierre Alain Gevenois: Imaging of Acute Appendicitis in Adults and Children. Springer.
  • A J Oschsner: A Handbook of Appendicitis. BiblioBazaar, 2009.
  • Duke Medicine News and Communications: Evolution of the Appendix: A Biological 'Remenant' No More, 2009. 
  • Appendix disorders Symptoms, Diagnosis, Treatments and Causes. (accessed 15/05/2016)


  • Vermiform appendix (ventral view) - Begoña Rodriguez
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