Next they try to image what is going on in your belly. An abdominal x-ray may detect fecalith as cause of appendicitis (5%). Free air due to perforation can might be seen on plain film.A barium enema may be used. It is an x-ray test where liquid contrast is used from anus to fill colon. Sometimes it show an impression on colon in area of inflamed appendix. Barium enema also can exclude other intestinal problems that mimic appendicitis.
Ultrasound shows an enlarged appendix or an abscess. Ultrasound is painless, but appendix can be seen in only half of patients. Ultrasound also is helpful in excluding problems with ovaries, fallopian tubes and uterus. Ultrasound machine usually looks like a small thumb on wheels that they bring into your room. Technician puts gelly on and drives probe over you belly.
Often they go straight to CT Scan (computer tomography). Especially if patient is not pregnant. CT scan gives relatively high irradiation of your body by x-rays. However benefits of prompt diagnose of appendicitis outweigh risk of radiation. CT scan gives slicing images of your body.
What do they look for? As any inflamation causes edema, wall of appendix will be thickened. This is actually a defensive mechanism - by edema organism try to wall of, to seal off area of infection and inflamation.
But it is useful for us because we can surely say there is an inflammation. The same goes for ultrasound.
CT scan is expensive - around 1000 dollars in an American hospital, though 40 dollars in Russia.
If CT scan is taken during night, CT image may be send to Australia Russia or India.
An American radiologist is paid around 40 dollars to read just an X-ray film. I guess he gets more for reading CT scan. It is only 5 dollars in India. This is why even such clinics as Harvard and Yale adopt this model of work - they send CT scans to cheap labor abroad. Especially during night. Half an hour later fax from Australia arrives. "Inflammatory pericecal mass in right iliac fossa consistent with diagnosis of severe acute appendicitis." Any doctor can read an x-ray film or CT scan. Radiologists are doctors who specialize in reading of films. They may find what was missed by others.
At this point diagnosis is usually clear. In cases if it is not, there is Laparoscopy. Laparoscopy is a surgical procedure. Small fiberoptic tube with a camera is inserted into abdomen through a small puncture in abdominal wall.
Yet there is no test that will diagnose appendicitis with 100% certainty.
The position of appendix may vary. If it is longer than normal, appendix may go deep down into pelvis. It also may move behind colon (called a retro-caecal appendix). From one hand it is better because retro-caecal appendix has less chances to burst into peritoneal cavity, from other it is difficult to diagnose and it is difficult to approach surgically. Inflammation of other organs, for example, female pelvic organs, may resemble inflammation of appendix. Pregnant women may have appendix pushed up in abdomen by enlarged uterus. Athletic young adults may tolerate more pain and may have not so obvious symptoms of appendicitis. Old patients may have vague symptoms as well.