Early symptoms of acute appendicitis may include:
- constipation, diarrhea, or gas
- dull pain beginning around the navel, turning to sharp pain in the lower right portion of the abdomen– this takes place over about 2 hours
- migrating pain (pain that shifts) – this occurs in 50 – 60% of cases
- loss of appetite
- low fever (37°C to 39°C)
- nausea and vomiting
- tenderness when pressure is applied in the lower right abdomen; a good indicator of appendicitis is rebound tenderness (this means it hurts less when the fingers press over the tender area than it does when the pressure is suddenly released)
These are the classic symptoms common in adolescents and young adults. In younger children, pain is less localized and there may be no tender points. In older adults, there is generally less pain.
Symptoms of more advanced appendicitis include:
- abdominal swelling and rigidity
- pain on the right side of the abdomen when pressed on the left side
These are both signs that inflammation has spread to the abdominal cavity or peritoneum. Left untreated, appendicitis will proceed from mild to severe symptoms. When the infection has reached this stage, it's called peritonitis, which is life-threatening, and a doctor should be seen immediately.
During the first 24 hours after first symptoms develop, about 90% of people develop inflammation. In some patients, inflammation is accompanied by necrosis ("tissue death") of the appendix, which places them at an increased risk for perforation of the appendix.
The great danger in appendicitis is rupture or perforation of the appendix. All the inflammatory agents and bacteria in the appendix spill out into the abdominal cavity, causing severe peritonitis. Sometimes there's mild peritonitis even before the appendix ruptures.
Occasionally, a mass of scar tissue forms an abscess around the appendix. In some ways, this reduces risk, since it insulates the abdomen from the dangerous pus inside. It tends to complicate surgery, however, often requiring two operations.