PEDIATRICS Vol. 107 No. 5 May 2001, pp. 1231-1231

Computed Tomography in Diagnosing Suspected Appendicitis

To the Editor.

In the September 1999 issue of Pediatrics, Garcia Peña et al¹ review their experience in using computed tomography (CT) to aid in the diagnosis of suspected cases of appendicitis. They conclude that any of a variety of strategies employed using CT scans resulted in reduced costs and improved diagnosis, management, and outcome for children with appendicitis. The authors should be complimented for a rigorous examination of data from a large series of patients. The study has generated considerable attention in the lay press, with Time magazine among others reporting on the diagnostic value of CT scanning in possible cases of appendicitis in children. As a pediatric surgeon, I have had several families inquire since the publication of this article about whether I would be ordering a CT scan on their child who was being evaluated for appendicitis.

The diagnosis of appendicitis in childhood can be an extremely difficult one to make, and the ability to use CT scanning to assist in making that diagnosis is apparent from the data in the article. I feel less certain, however, that the article justifies the routine use of CT scans for all equivocal cases of suspected appendicitis. In particular, a large part of the conclusion is based on cost savings, increased diagnostic accuracy, and shorter hospital stays, which are figured using a normal appendectomy rate of 23.2%. Although the authors allude to false-negative rates of up to 45% (in adult patients) with the clinical diagnosis^2,3 and up to 20% in children with acute appendicitis seen in the emergency setting,^4-7 these figures may substantially exceed the rate seen in settings where the early involvement of experienced pediatric surgical personnel is obtained. In particular, I would refer the authors to another of their own citations, the series of Putnam, Gagliano, and Emmens.⁸ Over a 5-year period in an era that predated the routine use (or availability) of either CT or ultrasound to assist in diagnosis, they had a negative appendectomy rate of 1.7% (7 of 406 operations). I wonder how the conclusions of the article would be altered if a negative appendectomy rate of 1.7% was used in place of the 23.2%. Regardless, the series of Putnam et al supports the concept that the clinical acumen of a pediatric surgeon can be superior to CT scanning (whose sensitivity and specificity was only 97%).

Additionally, several other issues bear mentioning related to the conclusions drawn. The technique of CT scanning employed used administration of oral gastrograffin. My experience in evaluating patients with possible appendicitis would indicate that a high percentage are vomiting at the time of presentation and thus might tolerate oral gastrograffin very poorly and even be at risk for aspirating it. Also, the availability to get a CT scan performed expeditiously and read by a staff radiologist within a few hours of presentation is probably not routine in many teaching hospitals. Variance of standards of care here would also diminish the efficacy of using CT in the emergency setting.

My own sentiment is that CT scanning in the emergency setting in assisting in diagnosing appendicitis has a role, but it should be a highly selective one, which should be used only after an experienced pediatric surgeon has had the chance to exercise his or her clinical judgment.

John Lawrence
Department of Surgery
University of New Mexico
Albuquerque, NM 87131

REFERENCES

1. Garcia Peña BM, Taylor GA, Lund DP, Mandl KD Effect of computed tomography on patient management and costs in children with suspected appendicitis. Pediatrics. 1999; 104:440-446 [Abstract/Free Full Text]
2. Izbicki JR, Knoefel WT, Wilker DK, Accurate diagnosis of acute appendicitis: a retrospective and prospective analysis of 686 patients. Eur J Surg. 1992; 158:227-231 [Medline]
3. Berry J Jr, Malt RA Appendicitis near its centenary. Ann Surg. 1984; 200:567-575 [Medline]
4. Reynolds SL Missed appendicitis in a pediatric emergency department. Pediatr Emerg Care. 1993; 9:1-3 [CrossRef][Medline]
5. Trautlein JJ, Lambert RL, Miller J Malpractice in the emergency department-review of 200 cases. Ann Emerg Med. 1984; 13:709-711 [CrossRef][Medline]
6. Rothrock SG, Skeoch G, Rush JJ, Johnson NE Clinical features of misdiagnosed appendicitis in children. Ann Emerg Med. 1991; 20:45-50 [Medline]
7. Rusnack RA, Borer JM, Fastow JS Misdiagnosis of acute appendicitis: common features discovered in cases after litigation. Am J Emerg Med. 1994; 12:397-402 [CrossRef][Medline]
8. Putnam TC, Gagliano N, Emmens RW Appendicitis in children. Surg Gynecol Obstet. 1990; 170:527-532 [Medline]

In Reply.

We reported in these pages the results of a retrospective chart review and decision analysis of children admitted from 1996 to 1997 for suspected appendicitis.¹ We found that several strategies using CT with intravenous and oral contrast both reduced costs and improved outcomes for children with suspected appendicitis. We subsequently performed a prospective cohort study from July to December 1999 evaluating the use of a clinical practice protocol involving ultrasonography and computed tomography with rectal contrast to diagnose appendicitis in children with equivocal presentations.² This ultrasound-CT protocol demonstrated a 94% accuracy, sensitivity, and specificity.

In our model, we used a 23% negative appendectomy rate based on our retrospective review. Dr Lawrence states that the published figures of 20% in the literature substantially exceed the rate seen in settings where early involvement of a pediatric surgeon is obtained. Besides the Putnam article,³ we can find no other studies to support this. Instead, published articles on acute appendicitis report established negative appendectomy rates between 10% and 20%.^4-7 In addition, previous reports have demonstrated that the sensitivity of clinical diagnosis by surgeons for acute appendicitis is as low as 63%⁸ and has never approached the 97% sensitivity for CT scan that we found in our model. Our prospective study confirms this high sensitivity.²

Dr Lawrence is absolutely correct that children tolerate oral gastrograffin very poorly. However, the children in our clinical practice protocol that we studied prospectively received rectal contrast only.² Dr Lawrence's comments about the availability of staff radiologists to interpret the radiographic imaging studies are more appropriate to situations relying on ultrasound rather than CT. At our institution, staff radiologists are available to interpret studies during the day and the fellows, under the supervision of the staff, interpret the studies at night. CT with rectal contrast is easy to perform and interpret and is quickly learned by radiologists-in-training. In addition, CT is not nearly so operator-dependent as is ultrasound for diagnosing appendicitis.

We fully agree with Dr Lawrence that the evaluation of children with suspected appendicitis, whether or not CT scans are used, should be made in consultation with an experienced pediatric surgeon. In this manner, we might be able to decrease both our negative appendectomy and perforation rates as well as to decrease the costs involved with in-hospital observation time.

Barbara M. Garcia Peña
George A. Taylor
Dennis P. Lund
Kenneth D. Mandl
^* Department of Medicine, Division of Emergency Medicine
 Department of Radiology
^§ Department of Surgery
Children's Hospital
Harvard Medical School
Boston, MA 02215

REFERENCES

1. Garcia Peña BM, Taylor GA, Lund DP, Mandl KD Effect of computed tomography on patient management and costs in children with suspected appendicitis. Pediatrics. 1999; 104:440-446
2. Garcia Peña BM, Mandl KD, Kraus SJ. Ultrasonography and limited computed tomography in the diagnosis and management of appendicitis in children. JAMA. 1999;1041-1046
3. Putnam TC, Gagliano N, Emmens RW Appendicitis in children. Surg Gynecol Obstet. 1990; 170:527-532
4. Deutsch A, Shani N Are some appendectomies unnecessary? J R Coll Edinb. 1983; 28:35-40
5. Pieper P, Kager L, Nasman P Acute appendicitis: a clinical study of 1018 cases of emergency appendectomy. Acta Chir Scand. 1982; 148:51-62 [Medline]
6. John H, Neff U, Kelemen M Appendicitis diagnosis today: clinical and ultrasonic deductions. World J Surg. 1993; 17:243 [CrossRef][Medline]
7. Gurleyik E, Gurleyik G, Unalmiser S Accuracy of serum C-reactive protein measurements in diagnosis of acute appendicitis compared with surgeon's clinical impression. Dis Colon Rectum. 1995; 38:1270 [CrossRef][Medline]
8. Wade DS, Marrow SE, Balsara ZN, Accuracy of ultrasound in the diagnosis of acute appendicitis compared with the surgeon's clinical impression. Arch Surg. 1993; 128:1039-1044 [Abstract/Free Full Text]