Appendicitis

Appendix

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.

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. 

Investigations

• 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.

Management

• 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.

Complications