Appendicitis is swelling of the appendix following an infection. Usually, this infection occurs through the oral route following ingestion of contaminated food or water. 

Acute appendicitis is the most common cause of acute surgical abdomen – infections within the abdomen requiring surgery. It is located at the junction of small and large bowel. A severe infection can cause gangrene and rupture of the infected appendix with leak of intestinal contents into the abdomen. 

Cases of appendicitis can be classified as

1) Acute appendicitis without perforation

2) Acute appendicitis with peritonitis

3) Acute appendicitis with local mass & abscess (pus formation)

Thus, an untreated inflamed appendix can spread infection from its innermost layer to all its four layers and finally, to the general abdominal cavity causing abscess (pus formation), rupture, severe peritonitis and even death.

Appendicitis can affect people at any age, though most common in the age groups 10 to 30 years.

Appendicitis is determined by environmental rather than genetic factors. It is more common in non- vegetarian people than those on a high fiber diet. The familial incidence may be attributed to an inherited malformation of the appendix.

The exact cause of appendicitis is unknown. It may occur after a viral infection in the digestive tract or when the opening of the appendix is blocked. Most of the nutrient absorption is completed by the terminal ileum and contents left behind form stools. The appendicular lumen blockage can occur by a fecolith – a hard stone formed from a stool particle. Blockage of the lumen can also occur following swelling of the lymphoid tissue in the appendix. In the absence of luminal obstruction, the acute attack can subside spontaneously. Also, even when the acute attack settles, the appendix never regains its original state. The adhesions and kinking (due to sticking to adjacent organs or the abdominal wall) may lead to a final episode of acute obstructive appendicitis. The inflammation can cause infection, pus formation, or rupture of the appendix with release of toxic fluid into the abdomen. This explains the natural course of the disease and its seriousness. 

The classic story of acute appendicitis begins

1. Pain in the middle of the abdomen 
2. Next pain moves to the right side of the abdomen where the appendix is located
3. Next pain spreads to all over the abdomen

Occasionally, there is no history of shift in the pain because pain may have started during sleep or mild pain can have gone un-noticed. The severity and duration of pain is very variable. An acute non-obstructed appendix may take 3-4 days. The other symptoms include:

1. Nausea – sensation of vomiting
2. Vomiting
3. Constipation
4. Diarrhoea occasional
5. Inability to pass gas
6. Initially low grade & later high grade fever
7. Abdominal swelling, Bloated abdomen
8. Anorexia

The history and physical examination will generally lead to the correct diagnosis. Until now, the most accurate non-invasive method of diagnosis is ultrasonography, though it is operator dependent. CT scan is gold standard for diagnosing acute appendicitis. The cost of CT scan is a deterrent factor.  However, in cases where ultrasonography remains inconclusive, CT scan is preferred. 

The suspicion & diagnosis of acute appendicitis is mainly clinical.  Together with other supporting investigation – blood tests, X ray chest & abdomen, Ultrasound and occasionally CT scan. 

Best treatment of appendicitis is its surgical removal. Mild appendicitis may be cured with oral or intravenous antibiotics.  A trial of antibiotics either oral or intravenous can be given. Such patients should be reviewed to assess response to treatment. In more serious cases especially with abdominal signs on clinical examination, treatment with surgery to remove the appendix is indicated. A surgeon may opt for appendicectomy or laparoscopic appendicectomy. The laparoscopic technique usually involves making three tiny cuts in the abdomen. The laparoscopic surgeon delivers the appendix with the help of specialised laparoscopic instruments. 

Almost all cases of acute appendicitis can be treated laparoscopically. Laparoscopic appendectomy is a useful method for reducing hospital stay, complications and return to normal activity. The main advantages are:

1. Less post-operative pain

2. Faster recovery

3. Short hospital stays

4. Lesser post-operative complications like wound infection and adhesion

5. Cost-effective in working people

6. Early return to normal activity and work.

7. Rest of the abdominal organs can also be examined.

Laparoscopic surgery is performed under general anesthesia. Any patient who is unfit for general anesthesia, is also unfit for laparoscopic surgery. Patients with pulmonary and cardiac diseases are risk for general anesthesia and thus, not considered as good candidates for laparoscopic appendectomy.  Laparoscopic appendectomy may also be more difficult in patients who have had previous lower abdominal surgery.  The elderly may also be at increased risk for complications with general anesthesia combined with pneumoperitoneum. Also, Laparoscopic surgery is difficult in complicated appendicitis with pus, perforation and abscess formation. 

The complications are:

A) Early

1. Bleeding – usually within 72 hours after surgery.
2. Visceral Injury – following injury while making trocars for surgery
3. Persistent pus from appendicular stump, abdominal wall
4. Intra-abdominal abscess – following a perforated appendix
5. Post-operative ileus / obstruction – following a generalized peritonitis or adhesions
6. Leakage of intestinal contents due to dying of appendicular stump due to severe infection

B) Late

1. Abdominal wall hernia – infection in the wound or drain tube site
2. Incomplete appendectomy – if appendix is kinked or adherent to adjacent caecum
3. In the hands of an experienced laparoscopic surgeon, these complications are minimal.

There are no medically proven ways to prevent appendicitis. However, appendicitis is found to be less common in people who eat foods containing fiber such as vegetables and fruits.

Usually one or more episodes precede a full-blown acute attack. However, it remains an area of controversy.