The performance of scores such as the Alvarado score and the Pediatric Appendicitis Score, however, are variable.The Alvarado score is the most known scoring system. A score below 5 suggests against a diagnosis of appendicitis, whereas a score of 7 or more is predictive of acute appendicitis. In a person with an equivocal score of 5 or 6, a CT scan or ultrasound exam may be used to reduce the rate of negative appendectomy. Pathology
Even for clinically certain appendicitis, routine histopathology examination of appendectomy specimens is of value for identifying unsuspected pathologies requiring further postoperative management. Notably, appendix cancer is found incidentally in about 1% of appendectomy specimens.Pathology diagnosis of appendicitis can be made by detecting a neutrophilic infiltrate of the muscularis propria. Periappendicitis, inflammation of tissues around the appendix, is often found in conjunction with other abdominal pathology. Differential diagnosis
Children: Gastroenteritis, mesenteric adenitis, Meckels diverticulitis, intussusception, Henoch–Schönlein purpura, lobar pneumonia, urinary tract infection (abdominal pain in the absence of other symptoms can occur in children with UTI), new-onset Crohns disease or ulcerative colitis, pancreatitis, and abdominal trauma from child abuse; distal intestinal obstruction syndrome in children with cystic fibrosis; typhlitis in children with leukemia. Women: A pregnancy test is important for all women of childbearing age since an ectopic pregnancy can have signs and symptoms similar to those of appendicitis.
There is pain in the sudden release of deep tension in the lower abdomen (Blumberg sign). If the appendix is retrocecal (localized behind the cecum), even deep pressure in the right lower quadrant may fail to elicit tenderness (silent appendix). This is because the cecum, distended with gas, protects the inflamed appendix from pressure. Similarly, if the appendix lies entirely within the pelvis, there is typically a complete absence of abdominal rigidity. In such cases, a digital rectal examination elicits tenderness in the rectovesical pouch. Coughing causes point tenderness in this area (McBurneys point), historically called Dunphys sign. Causes
Acute appendicitis seems to be the result of a primary obstruction of the appendix. Once this obstruction occurs, the appendix becomes filled with mucus and swells. This continued production of mucus leads to increased pressures within the lumen and the walls of the appendix. The increased pressure results in thrombosis and occlusion of the small vessels, and stasis of lymphatic flow. At this point, spontaneous recovery rarely occurs. As the occlusion of blood vessels progresses, the appendix becomes ischemic and then necrotic. As bacteria begin to leak out through the dying walls, pus forms within and around the appendix (suppuration). The result is appendiceal rupture (a burst appendix) causing peritonitis, which may lead to sepsis and in rare cases, death. These events are responsible for the slowly evolving abdominal pain and other commonly associated symptoms.The causative agents include bezoars, foreign bodies, trauma, intestinal worms, lymphadenitis and, most commonly, calcified fecal deposits that are known as appendicoliths or fecaliths.