Do all patients with suspected appendicitis benefit from CT imaging in community-based emergency departments?

The classic presentation of acute appendicitis involves the orchestrated complaint of vague periumbilical pain that localizes to the right lower quadrant and is accompanied by anorexia, nausea and emesis. However, this classic presentation is not usually the rule and approximately 15 to 21% of all appendectomies performed are unnecessary. The diagnosis has been particularly difficult in young children, elderly patients, and especially in women of childbearing age. In the latter, the negative appendectomy rate can be as high as 40 to 47%.

It is difficult to directly compare the results of different studies that have used computed tomography (CT) scan to evaluate patients for appendicitis due to the use of various exclusion and inclusion guideline criteria, different CT scanning techniques and protocols that use or do not use any combination of oral, rectal, and IV contrast. Several reports do not support the use of CT scan over surgical evaluation to increase the accuracy of diagnosing appendicitis. (1,2) In fact, a period of active in-hospital observation demonstrated the ability to yield a low negative appendectomy rate. (3) In contrast, significant evidence has been compiled to support its use in adults as a tool to improve accuracy and decrease misdiagnosis without an increase in the perforation rate. (4-6) Perforation of the appendix is usually higher in patients who delay seeking hospital care, the elderly, and in patients with nonclassic presentations. In the last two instances, the use of CT scans improves accuracy and enables the identification of an alternate diagnosis in 6 to 66.2% of patients. (6,7) In fact, in cases of suspected appendicitis, nonpregnant women of child-bearing age benefit the most from the routine use of CT scans and achieve a significant reduction in the negative appendectomy rate.

In community-based hospital emergency rooms, specialty consultants may not be readily available and CT scan interpretation by an experienced radiologist can facilitate the diagnosis in a patient that presents with right lower quadrant pain. Holloway et al (8) reported that a protocol that used CT scans in a community hospital to evaluate patients with suspected appendicitis led to a reduction in the negative appendectomy rate and allowed an alternate diagnosis to be made in 36% of patients. What is relevant in Chiumento et al's (9) study is that routine evaluation with CT scan in a community-based emergency department significantly reduces the negative appendectomy and perforation rate only in women between the ages of 15 and 55 without significant detrimental effects on the rest of the patients. It is implied that an alternate diagnosis was made in those who did not have their appendix removed. However, in neither study is it clearly established whether a surgeon was involved in the decision to obtain the scan. Selection of patients by surgeons to obtain a CT scan has been a factor in studies that have demonstrated a high accuracy for this technique and a low negative appendectomy rate. (5,10)

Reliance on CT scan should not distract the clinician from a careful history and physical examination. The era of clinical diagnosis of appendicitis has not come to an end, especially for adult men in whom routine use of CT scan has not proved better than surgical evaluation. (5,6,11) Because of the potential detrimental effects of radiation exposure and either enteral or IV contrast administration, establishing a clinical pathway that efficiently selects those who will be routinely assessed with CT scan may help establish appropriate management and therapy for patients with right lower quadrant abdominal pain.

References

1. Morris KT, Kavanagh M, Hansen P, et al. The rational use of computed tomography scans in the diagnosis of appendicitis. Am J Surg 2002;183:547-550.

2. Perez J, Barone JE, Wilbanks TO, et al. Liberal use of computed tomography scanning does not improve diagnostic accuracy in appendicitis. Am J Surg 2003;185:194-197.

3. Jones PF. Suspected acute appendicitis: trends in management over 30 years. Br J Surg 2001;88:1570-1577.

4. Jacobs JE, Birnbaum BA. CT imaging in acute appendicitis: techniques and controversies. Semin Ultrasound CT MR 2003;24:96-100.

5. Naoum JJ, Mileski WJ, Daller JA, et al. The use of abdominal computed tomography scan decreases the frequency of misdiagnosis in cases of suspected appendicitis. Am J Surg 2002;184:587-590.

6. Neumayer L, Kennedy A. Imaging in appendicitis: a review with special emphasis on the treatment of women. Obstet Gynecol 2003;102:1404-1409.

7. Storm-Dickerson TL, Horattas MC. What have we learned over the past 20 years about appendicitis in the elderly? Am J Surg 2003;185:198-201.

8. Holloway JA, Westerbuhr LM, Chain J, et al. Is appendiceal computed tomography in a community hospital useful? Am J Surg 2003;186:682-684.

9. Mathis RD, Chiumento AB, Yeh B, et al. An Outcome Study of the Use of Computed Tomography for the Diagnosis of Appendicitis in a Community-based Emergency DepartmentSouth Med J 2005;98:1169-1172.

10. Rao PM, Rhea JT, Novelline RA, et al. Effect of computed tomography of the appendix on treatment of patients and use of hospital resources. N Engl J Med 1998;338:141-146.

11. Paulson EK, Kalady MF, Pappas TN. Clinical practice. Suspected appendicitis. N Engl J Med 2003;348:236-242.

To one who has faith, no explanation is necessary. To one without faith,
no explanation is possible.
--St. Thomas Aquinas

Joseph J. Naoum, MD, FACS 

From the Department of Surgery, University of Texas Medical Branch, Galveston, TX.

Reprint requests to Joseph J. Naoum, MD, FACS, Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555. Email: [e-mail]

Accepted August 25, 2005.