Chapter 1 Acute appendicitis

Acute appendicitis is nonspecific inflammation of the inner lining of the vermiform appendix that spreads to its other parts. Appendicitis is the most common acute surgical emergency of the abdomen. The incidence of acute appendicitis is around 7% of the population in the United States and in European countries. In Asian and African countries, the incidence is probably lower because of the dietary habits. Appendicitis occurs more frequently in males than in females, with a male-to-female ratio of 1.7:1.

From without inwards the structure of appendix is as follows:

1. Serous coat is composed of peritoneal coat, which covers the whole of the appendix except along the narrow line of attachment of the mesoappendix.

2. Muscle coat. It consists of outer longitudinal muscles and inner circular muscles as seen in case of small intestine. The longitudinal muscle is formed by coalescence of the three taeniae coli at the junction of the caecum and appendix. Thus the taeniae, particularly the anterior taenia may be used as a guide to locate an elusive appendix. The inner circular muscle is continuation of the same muscle in the caecum. The peculiarity of the musculature of the appendix is that there are a few gaps in the muscular layer called “hiatus muscularis”. Through this infection from the submucosal coat directly comes to peritoneum and regional peritonitis occurs.

3. Submucosal coat. The submucous coat of the appendix is very rich in lymphoid tissue. It contains lymphoid follicles which are known as “abdominal tonsil”.

4. The mucous coat resembles that of large intestine.

Various anatomical positions of appendix are:

l. Retrocaecal position (the commonest irregular position – 70%) – the appendix lies behind the caecum although in majority of cases in an intraperitoneal location. Only in case of long retrocaecal appendix the tip of the appen­dix remains in the retroperitoneal tissue close to the ureter.

2. Pelvic position (second most common irregular position – 25%).

3. Subcaecal (2%).

4. Subhepatic (3%) – that means the tip of the appendix is towards the liver.

Aetiology of acute appendicitis:

1. Obstruction of the appendix lumen (fecoliths, hyperplasia of submucosal lymphoid follicle, intestinal helminthes, vegetables, fruit seeds, barium from previous X-rays).

2. The bacteriology flora. Most frequently seen organisms are Escherichia coli, enterococci, bacteroides (gram-negative rod), nonhaemolytic streptococci, anaerobic streptococci and CI. Welchii.

3. Diet which is relatively rich with fish and meat.

Appendicitis usually has 3 stages:

1. Ooedematous stage. Appendicitis may have spontaneous regression or may evolve to the second stage. The mesoappendix is commonly involved with inflammation.

2. Purulent (phlegmonous) stage. Spontaneous regression rarely occurs. Appendicitis usually evolves beyond perforation. Peritonitis may be possible.

3. Gangrenous stage. Spontaneous regression never occurs.

Kolesov’s classification of acute appendicitis (1952):

1. Appendicular colic.

2. Simple superficial appendicitis.

3. Destructive appendicitis:

а) phlegmonous;

b) gangrenous;

c) perforated.

4. Complicated appendicitis:

а)  appendicular mass;

b) appendicular abscess;

c) diffuse purulent peritonitis.

5. Other complications of acute appendicitis (pylephlebitis, sepsis, retroperitoneal phlegmon, local abscesses of abdominal cavity).