The vermiform appendix is considered by most to be a vestigial organ, its importance in surgery is only due to its tendency for inflammation resulting in the syndrome called acute appendicitis .
Acute appendicitis is the most common cause of an “acute abdomen” in young adults.
Appendectomy is the most frequently performed urgent abdominal operation
Despite extraordinary advances in the modern radiographic imaging & laboratory investigations, the diagnosis of appendicitis remains essentially clinical requiring a mixture of observation, surgical science & clinical sense.
The vermiform appendix is present only in mammals.
The position of the appendix is variable:
- Retrocecal 74%.
- Pelvic 21%.
- Postileal 5%.
- Paracecal 2%.
- Subcecal 1.5%.
- Preileal 1%.
The position of the base of the appendix is constant, being found at the confluence of the 3 taenia coli of the cecum which fuse to form the outer longitudinal muscle coat of the appendix.
The mesentery of the appendix (mesoappendix) arises from the lower surface of the mesentery of the terminal ileum.
The appendicular artery , a branch of the lower division of the ileocolic artery lie in the free border of the mesoappendix. It is an “end-artery”, thrombosis of which results in necrosis of the appendix (gangrenous appendicitis).
Finally, ischemic necrosis of the appendix wall produces gagrenous appendicitis , with free bacterial contamination of the peritoneal cavity.
Alternatively, the greater omentum & loops of small intestine become adherent to the inflamed app., walling off the spread of peritoneal contamination resulting in appendicular mass or paracecal abscess.
Rarely, appendiceal inflammation resolves leaving a distended mucus filled organ termed mucocele of the appendix.
The great threat of acute appendicitis is the potential for peritonitis , factors which promote this process: 1) extremes of age, 2) immunosupression, 3) D.M., 4) fecolith obstruction of the appendix lumen, 5) a free lying pelvic appendix, & 6) previous abdominal surgery which limits the ability of the greater omentum to wall off the spread of peritoneal contamination.
In these situations a rapidly deteriorating clinical course is accompanied by signs of diffuse peritonitis & systemic sepsis syndrome.
The classical features of acute appendicitis begin with poorly localized colicky abdominal pain, due to midgut visceral discomfort in response to appendiceal inflammation.
Pain is frequently first noticed in the periumbilical region, associated with anorexia, nausea, once or 2 episodes of vomiting. Anorexia is constant feature especially in children.
With progressive inflammation, the parietal peritoneum in the rt. iliac fossa becomes irritated, producing intense more localized, constant somatic pain . Typically, cough or sudden movement exacerbates the rt. iliac fossa pain.
This typical sequence is present in 50% of cases. Atypical presentation is common: elderly (no localization), pelvic app. (no somatic pain, suprapubic discomfort & tenesmus).
No fever during the first 6 hours, then slight pyrexia (37.2-37.7), pulse rate (80-90).
Typically, 2 clinical syndromes of acute appendicitis: acute catarrhal (nonobstructive) & acute obstructive appendicitis . The latter is characterized by a much more acute course, the onset of symptoms is abrupt, with more tendency for perforation.
The diagnosis of acute appendicitis depends on clinical examination rather than history or investigations.
The main features : unwell patient, low grade fever.
Patient is asked to point where the pain began & to where it moved, (pointing sign).
Superficial palpation starting from the left iliac fossa, anticlockwise to the right iliac fossa, will detect muscle guarding over the point of maximum tenderness, classically McBurney’s point .
Asking the patient to cough or gentle percussion rebound tenderness.
Deep palpation over the left iliac fossa pain in the right iliac fossa (Rovsing’s sign).
If the appendix lies over the psoas muscle the patient will lie with the right hip flexed for pain relief (Psoas sign).
If the appendix is in contact with the obturator internus muscle, flexion & internal rotation of the hip pain in the hypogastrium (Obturator sign).
Special features – according to position of the appendix
Rigidity is often absent, even on deep pressure (silent appendix), as the cecum (distended with gas prevents the pressure exerted by the hand to reach the appendix.
+ve deep tenderness in the loin, with +ve psoas sign & pain on hyperextension of the hip joint.
Early diarrhea (rectal irritation), -ve abdominal rigidity, P/R: shows tenderness in the rectovesical or Douglas pouch. +ve psoas & obturator signs. If appendix is in contact with urinary bladder frequency of micturition.
If the condition of the patient is satisfactory, the standard treatment is the conservative Ochsner-Sherren regimen.
The inflammatory process is already localized & surgery is difficult & may be dangerous.
It may be impossible to find the appendix & a fecal fistula may form.
So, non-operative program is advised, to be prepared to operate if clinical deterioration occurs:
1) A rising pulse rate.
2) Increasing or spreading abdominal pain.
3) Increasing size of the mass.
4) Vomiting or increase gastric aspirate.
Careful record of the vital signs, regular abdominal examination, extent of the mass, it is helpful to mark the limits of the mass on the skin. A nasogastric tube with I.V. fluids & antibiotics therapy.
Clinical improvement is usually evident within 24-48 hrs. in 90% of cases.
Appendix should be removed after an interval of 6-8 weeks.