Pain in the right lower abdomen and raised infection parameters
In the case of an appendicitis it is always important to look for a possible cause. In many cases a fecolith is seen obstructing the appendix. Also an inflamed appendix can be secondary to other inflammatory bowel diseases. Especially in older patients an appendicitis can be caused by an obstructing cecal mass.
References
Puylaert JB. Ultrasonography of the acute abdomen: gastrointestinal conditions.Radiol Clin North Am. 2003 Nov;41(6):1227-42, vii. Review
Brown MA. Imaging acute appendicitis Semin Ultrasound CT MR. 2008 Oct;29(5):293-307. Review