ABSTRACT
Radiologic Imaging Imaging studies for suspected appendicitis are being ordered more and more frequently and have even been advocated by some for routine use.(9) Imaging itself can occasionally lead to more unanswered questions with nondiagnostic findings, such as increased appendiceal diameter or nonvisualization of the appendix with or without isolated RLQ fat stranding only. Nonetheless, use of imaging to aid the diagnosis for appendicitis has increased dramatically. Results from an analysis from 1991 to 1999 showed a threefold increase in the usage of preoperative CT or ultrasound (US) for appendicitis. Despite this rapid growth in imaging, the negative appendectomy rates have remained unchanged for virtually the same time period from 1987 to 1999.(10) Still CT and US both have good positive predictability at 97% and 94%,
respectively. More evidence has suggested that CT is more sensitive, specific, and accurate than US as well as more likely to detect an intra-abdominal abscess or phlegmon or an alternative diagnosis.(11-15) However, a negative test cannot rule out appendicitis and can still be associated with appendicitis in 12% of patients after CT and 30.5% of patients after US.(10) Furthermore, it is often unclear how to proceed and what the clinical consequences are when CT findings are equivocal or nondiagnostic findings exist. Daly et al. reviewed 1,344 CT scans of patients with the indication of suspected appendicitis with equivocal findings in 13% or 172 scans. Of those with equivocal CT findings, appendicitis was still found in 31%. Other factors such as appendiceal size have been used diagnostically with an average appendiceal diameter of 6 mm but studies of normal adults range from 3 mm to 10 mm.(16) In this same group of patients with equivocal CTs, appendiceal diameter on CT greater than 9 mm resulted in appendicitis 50% of the time, but still occurred in 13% of those with an appendiceal diameter less than 9 mm. Thus a significant overlap in appendiceal diameter exists between normal and abnormal appendices and size alone should not be used to confirm the diagnosis, but the diagnosis should also be based on appearance and presence of any other secondary signs of disease. (16) Appendicitis can still occur even when the appendix is not visualized on CT and no other findings are present. Fortunately, this event is seen in less than 2% of patients.(17, 18) However, nonvisualization with any amount of RLQ stranding or fluid resulted in appendicitis in 44% of patients.(19) CT is superior to US in correctly identifying appendicitis in adults, CT is likely to be more useful at the extremes of ages, and surgical evaluation prior to imaging may help reduce the number of unnecessary CT scans. Although many have advocated for the routine use of radiologic imaging for appendicitis, several studies have shown that routine imaging often adds minimally to the diagnostic accuracy for appendicitis and that an accurate history and physical are oftentimes all that are needed to attain the diagnosis.(20)
The patient is given 2 l of lactated ringers, IV ceftriaxone and metronidazole in the emergency department and brought immediately to the operating room and explored laparoscopically. Purulent fluid is seen on entry to the abdomen with adhesions present in the RLQ surrounding an inflammed cecum and terminal ileum. After much manipulation the appendix is visualized and found to be grossly inflamed and perforated at the base of the cecum. The surrounding tissue is difficult to handle due to the inflammation and adhesions.
