Appendicitis

Although the clinical presentation of appendicitis has not changed considerably since its first description in 1886 by Reginald Fitz, its mortality has diminished dramatically since Willard Packard performed the first surgery in 1867. It is one of the most common surgical diseases, annually affecting 233 per 100,000 people in the United States. The highest incidence is in 10–19-year-olds and is more common in men (8.6% lifetime incidence vs. 6.7% in women). The appendix is retrocecal in 65% of patients and is in the pelvis in 20%. This variability contributes to the difficulty in diagnosing appendicitis. Appendicitis is caused by luminal obstruction leading to edema, venous congestion, arterial insufficiency, ischemia, necrosis, and ultimately perforation. Stimulation of the visceral nervous system is transmitted through slow C fibers to T-10 and is inferred as originating from the umbilicus. Eventually, the parietal peritoneum is irritated and the somatic nervous system interprets the location in the right lower quadrant (RLQ).