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Appendicitis is a common cause of abdominal pain. 7% of the population will get appendicitis in one’s lifetime. The appendix is a hollow worm like structure attached on one end to the cecum (the first part of the colon in the right lower abdomen), but freely mobile at the other end. The appendix varies in length between about 2 and 4 inches, contains debris and sometimes little “stones” called “fecaliths”.

These are composed of hardened old stool and debris and they tend to enlarge over the years as layer upon layer is added. At one point such a fecalith can be big enough that it can block the entrance to the appendix from the cecum and the E. coli bacteria normally present in the appendix start invading the wall of the appendix causing an acute inflammation.

Appendix abscess

Pus forms now in this close off space inside the appendix. Pus in an enclosed space is called an abscess and at this stage things deteriorate rapidly. The inflamed wall of the appendix is producing inflammatory secretions, which are under pressure and are an excellent growth medium for the bacteria in the area. With the pus being under pressure and the appendix wall being eroded from inside, it is no surprise that only within a few hours there can be a rupture of the appendix and the infection spreads into the abdominal cavity, called peritonitis.

With good medical care this should no longer happen. Once the pus is pouring into the abdominal cavity, all of the bacteria flow with it into the space between the bowels and the back of the abdominal cavity. Normally this is a sterile environment. Bacteria, particularly E. coli and Klebsiella that are normally found inside the cecum and appendix, can very quickly invade through the peritoneal lining into the blood stream and cause a dangerous form of septicemia. It goes without saying that every effort must be directed at diagnosing appendicitis early and to get quick surgical treatment for this condition to prevent perforation of an abscessed appendix and septicemia.

Mortality rates now and in the 1800’s

The death rate before surgery was introduced to treat this condition was 80% to 100% and because of peritonitis and septicemia. However, in the late 1800’s appendectomy (the surgical removal of the inflamed appendix) was introduced in the United States, followed by England and Europe in 1902, which improved survival rates dramatically.

The mortality rates now are less than 1%. However in the elderly, where symptoms can be masked as being mild despite very severe findings on surgery, the mortality rates remain about in the 5% to 15% range (Ref. 27 ). A ruptured appendicitis with peritonitis, treated with antibiotics and delayed surgery still has a mortality rate of 10% to 20% regardless of age.

Some statistics about diagnosing appendicitis

This is why every abdominal pain has to be taken seriously. Better to check a few times too often instead to risk missing appendicitis once. At a conference for Emergency physicians and family physicians we were told that 5% of all malpractice suits against physicians are due to a missed appendicitis.

In the setting of a walk-in-clinic about 2% to 3% of all abdominal pain is due to appendicitis. In a hospital setting about 30% of children admitted with abdominal pain have appendicitis. During an epidemic of gastroenteritis in school children there will always be a few children who do not have gastroenteritis, but require surgery for appendicitis. It is a challenge to the physician to have an index of suspicion and spot these cases.



Appendicitis symptoms

Typically the onset of appendicitis is acute with central or upper central (epigastric) pain in the abdomen, which will change within a few hours to lower abdominal pain migrating into the right lower abdomen. In 1 in 2000 cases the symptoms localize to the left lower abdomen as about that many people have a “situs inversus” (meaning that the intraabdominal organs including the appendix are congenitally placed on the opposite site). This is not a problem provided the physician will think about it.

Symptoms different for appendicitis and gastroenteritis

Vomiting is common and occurs after the onset of pain. The vomiting is due to a reaction of the peritoneal irritation as a result of the inflamed appendix. As it takes some time for the peritoneum to get irritated, the pain is first, the vomiting is second with appendicitis. This is contrary to gastroenteritis, which is more common than appendicitis. With gastroenteritis the inflamed lining of the stomach and the intestinal wall leads to acute vomiting first, subsequently this is followed by a pain, which is much more diffuse than with appendicitis. As this is an important distinction, I am going to repeat this here in a simpler way.

The following helps to distinguish between stomach flu and appendicitis


APPENDICITIS: abdominal pain first, then vomiting

STOMACH FLU (=gastroenteritis): vomiting first, then diffuse abdominal pain


The psoas sign

Because the abdominal pain with appendicitis is due to peritoneal irritation, there is an involuntary reflex tightening of abdominal wall muscles, which helps the physician to come to the appropriate diagnosis. If the free end of the appendix has moved under the cecum in close proximity to the iliopsoas muscle, the person may limp because with every step this muscle moves and causes pain from the appendicitis. The limp is then an indirect indicator of the appendicitis (doctor lingo: “psoas sign”). Other symptoms are a fever, a fast heart beat, lack of appetite, nausea, vomiting.

An older patient does not express these symptoms and signs as much. Very young patients may have absent signs and symptoms or may have problems communicating them. The physician must be particularly careful and thorough in the very young and old before excluding an appendicitis in order to avoid a false negative diagnosis, which would lead to perforation, septicemia and a high risk of death. This is the reason why there are still a very high percentage of perforation rates in the elderly (60% to 70% according to Ref. 27).

Diagnostic tests

The diagnosis of appendicitis is a clinical one. The physician relies heavily on the examination and watches whether there is tenderness in the right lower abdomen and rebound tenderness when the examining hand suddenly let’s go of the pressure.

A rectal examination depending on the location of the appendix will show tenderness as well. Other tests are blood tests, which usually show a leukocytosis (elevation of white blood cell count), but in elderly patients this can be normal. Ref. 27 states that the following three findings are the most reliable of them all: right lower abdominal pain, rigidity and migrating pain from the umbilical area to the right lower abdomen. A urinalysis will determine whether there are kidney stones or a urinary tract infection. In women a urine sample for pregnancy test can rule out a tubal (ectopic) pregnancy, which can mimic appendicitis. In the acute appendicitis case there is no room for CT scans and ultrasounds. But in a case involving a complex perforation with abscesses thee surgeon may order these tests prior to surgery.


As mentioned above once the clinical diagnosis of appendicitis is certain, the physician arranges surgery as soon as possible.

One of the rules in medicine is that the person has to have fasted for 6 hours before the anesthetist will do a general anesthetic. The reason for this is that the physician does not want the patient to vomit food. When this happens the patient can aspirate this into the lungs causing aspiration pneumonia. A good rule of thumb therefore for the public is to keep a person that they bring to the hospital for abdominal pain away from food and drink. The hospital personnel can start an intravenous access line and give intravenous fluids to keep the patient hydrated. This way, the surgeon can do surgery sooner thus minimizing the risk of perforation and peritonitis while waiting for the surgery.

Laparoscopic versus conventional appendectomy

The surgeon will decide what approach to take.  This could involve doing a laparoscopic appendectomy where he removes the  appendix through a stabbing wound rather than an incision. Alternatively, the surgeon may pursue the conventional surgery (an appendectomy) through a 1 ½ to 2-inch incision. The surgeon can do an uncomplicated appendectomy through a laparoscopy. However, the patient must understand that not infrequently there are adhesions. In this case the surgeon can not deal with this through a laparoscopy and he will change to the regular incisional approach.

Surgery when appendix perforated

Also, if there has been a perforation or there are pre-existing congenital conditions that thee surgeon needs to deal with, this also might be a reason why conventional surgery is needed. If perforation is present, the surgeon will start intravenous antibiotic therapy, swabs are taken during the surgery and a plastic drainage hose is left inside that is brought out through the abdominal wall and skin and is hooked up to a vacuum container. This will suck out secretions and bacteria to help the body overcome the infection together with the antibiotics. The surgery will take only 45 minutes in a straightforward case, but can be a 2-hour ordeal in a complex perforation. Depending on how much surgery the surgeon did, the post- surgical recovery varies from only a few days to 2 or three weeks.

For further info on appendicitis with images of psoas sign click on this link.


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Last modified: October 17, 2019