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Comparison of men and women presenting to an ED with acute appendicitis
Comparison of Men and Women Presenting to an ED With Acute Appendicitis DAVID A. GUSS, MD AND CHRISTOPHER RICHARDS, MD Appendicitis is a common problem presenting to the Emergency Department (ED). Missed or delayed diagnosis can result in increased morbidity and is a common cause of malpractice claims. Diagnosis in women is more difficult because of additional clinical considerations. The study hypothesis is that women with appendicitis presenting to an ED experience a longer delay to operative intervention resulting in an increased rate of perforated appendix. A retrospective chart review of 196 male and female patients between twelve and fifty years of age presenting to the ED with final discharge diagnosis of appendicitis was performed. Mean time from ED presentation to operative intervention was 477 minutes for men and 709 minutes for women (P ⴝ .02). Perforated appendix was present in 38.7% of men and 23.5% of women (P ⴝ .002). Women with appendicitis presenting to an ED experience significant delay to surgery, however, this is not associated with an increased rate of perforation. (Am J Emerg Med 2000;18:372-375. Copyright r 2000 by W.B. Saunders Company)
Appendicitis is a common disorder affecting people of both sexes as well as all ages and ethnic groups, with an estimated lifetime risk of appendicitis between 7% and 9%.1 Each year in the United States there are approximately 250,000 cases of appendicitis, the majority of which present initially to the emergency department (ED).1 Although improved diagnostic and therapeutic modalities have resulted in a dramatic decline of mortality to less than 1%, the incidence of perforated appendix has remained fairly constant, averaging between 13% and 39%.1-7 Current understanding of the pathophysiology of appendicitis is that it begins with luminal obstruction of the appendix followed by intraluminal hypertension and distention. If unrelieved, the appendiceal wall becomes ischemic which favors bacterial invasion and inflammation. Without interruption, this process will usually lead to gangrene and perforation.7 Although not proven, this pathophysiologic construct would support the notion that delay in diagnosis and treatment is associated with increased risk of perforation. A recent review of almost 5,000 patients undergoing nonincidental appendectomy identified a normal appendix in 13% and perforation in 21%.2 The diagnosing and treating physicians From the Department of Emergency Medicine, UCSD Medical Center, San Diego, CA, and the Department of Emergency Medicine, Brigham and Women’s Hospital, Boston, MA. Manuscript received June 16, 1999, returned July 6, 1999, revision received August 15, 1999, accepted September 11, 1999. Address reprint requests to David Guss, MD, Department of Emergency Medicine, UCSD Medical Center, 200 West Arbor Drive, San Diego, CA 92103-8676. E-mail: [email protected]. Presented at the Society for Academic Emergency Medicine Annual Meeting, May 1997. Key Words: Appendicitis, operative delay, perforation. Copyright r 2000 by W.B. Saunders Company 0735-6757/00/1804-0003$10.00/0 doi:10.1053/ajem.2000.7323
372
in tandem are challenged to simultaneously reduce the rate of perforation and not increase the rate of unnecessary appendectomy. Delayed or missed diagnosis of appendicitis is one of the most frequent causes of medical malpractice claims and settlements for emergency physicians.8,9 The reasons for delay are related to the often protean and highly variable historical and physical manifestations, the inconsistent course, and the formidable list of disease processes to be considered. Confusing the picture further is the likelihood that some cases of appendicitis can go on to resolve without operative intervention.10,11 The issue of differential diagnosis is even greater in women of childbearing age as uterine or adnexal disease may present in a manner clinically indistinguishable from appendicitis. Compared with men, women were noted to have a higher rate of normal appendix at surgery.1,2 A review of the medical literature does not reveal any study comparing men and women with respect to delay in operative intervention or incidence of perforation. The hypothesis of this study is that there is a greater delay in diagnosis and operative intervention for women of childbearing age with appendicitis compared with men in a similar age range and that, as a result, women have a higher incidence of perforated appendix. METHODS This study used a retrospective chart review design. The site was a University Medical Center ED in Southern California with an average annual census of 35,000 staffed by residents in emergency medicine, medicine, family medicine, and faculty board certified in emergency medicine. Inclusion criteria were broad and encompassed all patients between the ages of 12 and 50 years of age seen in the ED between 1989 and 1994 with a final hospital discharge diagnosis of appendicitis. All ED and inpatient records along with operative reports and pathological reports were reviewed. Historical data points included: age; sex; time placed in an ED examination room; history of nausea, vomiting, diarrhea, and anorexia; history of pelvic inflammatory disease or abdominal surgery; and time of operative incision. Physical examination data included: temperature, blood pressure, pulse rate, abdominal tenderness, tenderness at McBurney’s point, psoas sign, rebound tenderness, cervical motion tenderness, adnexal tenderness, and cervical discharge. Ancillary information included: white blood cell count (WBC), abdominal radiographs, abdominal or pelvic ultrasound, abdominal computed tomography (CT), and laparoscopy. All data were entered into a database and analyzed using SASS software (SASS, Cury NC). Student’s t test was used
GUSS AND RICHARDS 䊏 MEN AND WOMEN WITH APPENDICITIS
to compare age, time to operation, percentage perforated, percentage undergoing abdominal radiograph, abdominal CT and laparoscopy. Chi-squared analysis was used to compare percentages of men and women with nausea, vomiting, diarrhea, anorexia, prior abdominal surgery, tenderness at McBurney’s point, psoas sign, and rebound tenderness. Statistical significance was set at P ⬍ .05 (two-tailed). This study was approved by our Institutional Review Board. RESULTS Two hundred and seventy-seven patients were identified of whom 196 met all study inclusion criteria. Thirty-nine charts were either incomplete or unavailable for review and 42 others were excluded. Eighteen were excluded because appendectomy was performed incidental to another operative procedure and not because of a presentation suggestive of appendicitis. Nineteen were excluded because of presentation from a site other than the ED. Three patients had percutaneous drainage of a periappendiceal abscess and an appendectomy was performed on an elective basis at a later date. Two patients were excluded because of factors that were felt to bias the management decisions: one patient was the spouse of a surgical resident and the other experienced an inordinate delay in operative management because of parental consent issues. Of the 196 patients comprising the study population, 113 were men with a mean age of 26.5 and 83 were women with a mean age of 26.4 (P ⫽ .93). Key clinical, historical, and physical examination parameters are summarized in Table 1. There was no statistically significant difference between men and women with respect to nausea, vomiting, anorexia, diarrhea, or rebound tenderness. Mean total WBC was 15,500/mm3 in men and 15,200/mm3 in women (P ⫽ .55). Abdominal computed tomography was performed on two men and one woman. The rates of other ancillary imaging tests are summarized in Figure 1. The mean time to operation was 477 minutes for males and 709 minutes for women (P ⫽ .02). Perforated appendix was identified in 44 men (38.7%) and 21 women (23.5%) (P ⫽ .002). Mean time to surgery in women with perforated appendix was 1,140 minutes versus 561 minutes for women without perforation (P ⫽ .0004). Mean time to surgery for men with perforated appendix was 487 minutes versus 472 minutes for those without perforation (P ⫽ .84). These data are summarized in Figure 2. TABLE 1.
Characteristics of Study Patients
Age (years) Temperature (F) WBC (1000/mm3) Nausea (%) Vomiting (%) Diarrhea (%) Anorexia (%) Rebound Tenderness (%)
Male N ⫽ 113
Female N ⫽ 83
P
26.5 99.5 15.5 79.6% 66.1% 22.0% 78.5% 62.5%
26.4 99.1 15.2 86.6% 68.3% 21.0% 74.6% 52.0%
.93 .12 .55 .20 .74 .88 .57 .16
373
DISCUSSION In the cohort of patients studied, the time from presentation to the ED to operative intervention was 48% longer in women than men, supporting part one of the study hypothesis. This difference is even more dramatic when comparing the subgroup of patients with perforation, 1,140 minutes for women and 487 minutes for men. The delay in operative intervention could not be explained by differences in clinical history or findings on physical examination at the time of initial evaluation. Delay in women might be explained, in part, by the higher rates of use of diagnostic imaging tests such as abdominal or pelvic ultrasound and abdominal CT. The reasons for this are speculative but likely related to the broader range of diagnostic considerations in women. Part two of the study hypothesis is rejected by this investigation, as the increased time to operative intervention in women compared with men was not associated with an increased rate of perforated appendix. This finding is difficult to explain considering that women with perforation had a much greater mean delay in operative intervention than women without perforation (1,140 minutes versus 561 minutes). This study did not permit determination of time from symptom onset to surgical intervention. If women tended to present earlier after symptom onset than men, the actual time from symptom onset to surgical intervention might have been shorter for women. If future study were to substantiate such a pattern, it would offer some explanation for the lower perforation rate encountered in women. An alternative explanation for the observed perforation rates would require some gender-based difference in the inflammatory response that results in an increased risk of perforation in men relative to women. The concept that right lower quadrant pain in women of childbearing age is a more complex clinical problem than it is in men is not novel. Women have historically had higher rates of negative laparotomy.1,3 Rothrock reported on 174 nonpregnant women with appendicitis and noted that 33% were misdiagnosed.12 Anderson reported decreased diagnostic accuracy for appendicitis among women, particularly in the third decade of life.5 The need for improved diagnostic testing in the evaluation of patients with appendicitis is suggested by this study both from the perspective of the delay encountered in the women as well as the extremely high perforation rate in men. A variety of approaches have been investigated including ultrasound, helical CT, WBC scanning, clinical scoring systems, and neural networks.13-21 A recent study using helical CT scanning with rectal contrast reported a diagnostic accuracy of 98%.20,21 Laparoscopy has been suggested as a strategy to reduce the rate of negative laparotomy and the time delay to final diagnosis.22 Although this approach is likely to reduce the rate of negative laparotomy, it is still an invasive procedure with significant cost and potential morbidity and would probably be associated with a high rate of negative laparoscopy. There are several limitations to this study. The retrospective design compromised the ability to reliably collect all data points resulting in the elimination of many cases. This
374
AMERICAN JOURNAL OF EMERGENCY MEDICINE 䊏 Volume 18, Number 4 䊏 July 2000
FIGURE 1. Diagnostic testing. e male, 䊏 female.
particular study focused on only those patients with surgically confirmed appendicitis and did not consider all patients in whom the diagnosis of appendicitis was considered. As a result we cannot comment on the rates of false-positive laparotomy, or determine if there are important differences between men and women in this regard. Finally, the gender differences in the time to surgery identified in this study may be peculiar to this institution and to the ED setting and thereby not applicable to other locales.
FIGURE 2. Time to operation. e male, 䊏 female.
CONCLUSION Compared with men, women presenting to the ED with a final hospital discharge diagnosis of appendicitis are associated with a significantly longer delay in operative intervention. Despite this delay, women have a significantly lower rate of perforated appendix. The authors thank Marian Jasek for her thoughtful review and assistance with the preparation of this manuscript.
GUSS AND RICHARDS 䊏 MEN AND WOMEN WITH APPENDICITIS
REFERENCES 1. Addiss DG, Shaffer N, Fowler BS, et al: The epidemiology of appendicitis and appendectomy in the United States. Am J Epidemiol 1990;132:910-925 2. Hale DA, Molloy M, Pearl RH, et al: Appendectomy: A contemporary appraisal. Ann Surg 1997;225:252-261 3. Rogers H, Faxon HH: A statistical study of six hundred and seventy one cases of appendicael periotnitis. N Engl J Med 1942;226: 707-717 4. Pieper R, Kager L, Nasman P: Acute appendicitis: A clinical study of 1018 cases of emergency appendectomy. Acta Chir Scand 1982;148:51-62 5. Anderson RE, Ilugander A, Thulin AJ: Diagnostic accuracy and perforation rate in appendicitis: Association with age and sex of the patient with appendectomy rate. Eur J Surg 1992;158:37-41 6. Lewis FR, Holcroft JW, Boey J, et al: Appendicitis: A critical review of diagnosis and treatment in 1000 cases. Arch Surg 1975;110: 677-684 7. Greenfield RH, Henneman PL: Disorders of the small intestine, in Rosen P (ed): Emergency Medicine Concepts and Clinical Practice. St Louis, MO, Mosby, 1998, pp 2005-2022 8. Trautlein J, Lambert R, Miller J: Malpractice in the emergency department—Review of 200 cases. Ann Emerg Med 1984;13:709711 9. Rusnak R, Borer J, Fastow J: Misdiagnosis of acute appendicitis: Common features discovered in cases after litigation. Am J Emerg Med 1994;12:397-402 10. Migraine S, Atri M, Bret PM, et al: Spontaneously resolving acute appendicitis: Clinical and sonographic documentation. Radiology 1997;205:55-58
375
11. Barber M, McLaren J, Rainey J: Recurrent appendicitis. Br J Surg 1997;84:110-112 12. Rothrock SG, Green SM, Dobson M, et al: Misdiagnosis of appendicitis in nonpregnant women of childbearing age. J Emerg Med 1995;13:1-8 13. Zeidan BS, Wasser T, Nicholas GG: Ultrasonography in the diagnosis of acute appendicitis. J R Coll Surg Edinb 1997;42:24-26 14. Foley CR, Latimer RG, Rimkus DS: Detection of acute appendicitis by technetium 99 HMPAO scanning. Am Surg 1992;58: 761-765 15. Lane MJ, Katz DS, Ross BA, et al: Unenhanced helical CT for suspected acute appendicitis. Am J Roentgenol 1997;168:405-409 16. Teicher I, Landa B, Cohen M, et al: Scoring system to aid in diagnosis of appendicitis. Ann Surg 1983;198:753-759 17. Eriksson S: Acute appendicitis—Ways to improve diagnostic accuracy. Eur J Surg 1996;162:435-442 18. Edwards FH, Davies RS: Use of bayesian algorithm in the computer-assisted diagnosis of appendicitis. Surg Gynecol Obstet 1984;158:219-222 19. Alvarado A: A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med 1986;15:557-564 20. Rao P, Rhea J, Novelline R, et al: Helical CT combined with contrast material administered only through the colon for imaging of suspected appendicitis. Am J Roentgenol 1997;169:1275-1280 21. Rao P, Rhea J, Novelline R, et al: Helical CT technique for the diagnosis of appendicitis: Prospective evaluation of a focused appendix CT examination. Radiology 1997;139-144 22. Deutsch A, Zelikovsky A, Reiss R: Laparoscopy in the prevention of unnecessary appendectomies: A prospective study. Br J Surg 1982;69:336-337
Appendicitis is a common disorder affecting people of both sexes as well as all ages and ethnic groups, with an estimated lifetime risk of appendicitis between 7% and 9%.1 Each year in the United States there are approximately 250,000 cases of appendicitis, the majority of which present initially to the emergency department (ED).1 Although improved diagnostic and therapeutic modalities have resulted in a dramatic decline of mortality to less than 1%, the incidence of perforated appendix has remained fairly constant, averaging between 13% and 39%.1-7 Current understanding of the pathophysiology of appendicitis is that it begins with luminal obstruction of the appendix followed by intraluminal hypertension and distention. If unrelieved, the appendiceal wall becomes ischemic which favors bacterial invasion and inflammation. Without interruption, this process will usually lead to gangrene and perforation.7 Although not proven, this pathophysiologic construct would support the notion that delay in diagnosis and treatment is associated with increased risk of perforation. A recent review of almost 5,000 patients undergoing nonincidental appendectomy identified a normal appendix in 13% and perforation in 21%.2 The diagnosing and treating physicians From the Department of Emergency Medicine, UCSD Medical Center, San Diego, CA, and the Department of Emergency Medicine, Brigham and Women’s Hospital, Boston, MA. Manuscript received June 16, 1999, returned July 6, 1999, revision received August 15, 1999, accepted September 11, 1999. Address reprint requests to David Guss, MD, Department of Emergency Medicine, UCSD Medical Center, 200 West Arbor Drive, San Diego, CA 92103-8676. E-mail: [email protected]. Presented at the Society for Academic Emergency Medicine Annual Meeting, May 1997. Key Words: Appendicitis, operative delay, perforation. Copyright r 2000 by W.B. Saunders Company 0735-6757/00/1804-0003$10.00/0 doi:10.1053/ajem.2000.7323
372
in tandem are challenged to simultaneously reduce the rate of perforation and not increase the rate of unnecessary appendectomy. Delayed or missed diagnosis of appendicitis is one of the most frequent causes of medical malpractice claims and settlements for emergency physicians.8,9 The reasons for delay are related to the often protean and highly variable historical and physical manifestations, the inconsistent course, and the formidable list of disease processes to be considered. Confusing the picture further is the likelihood that some cases of appendicitis can go on to resolve without operative intervention.10,11 The issue of differential diagnosis is even greater in women of childbearing age as uterine or adnexal disease may present in a manner clinically indistinguishable from appendicitis. Compared with men, women were noted to have a higher rate of normal appendix at surgery.1,2 A review of the medical literature does not reveal any study comparing men and women with respect to delay in operative intervention or incidence of perforation. The hypothesis of this study is that there is a greater delay in diagnosis and operative intervention for women of childbearing age with appendicitis compared with men in a similar age range and that, as a result, women have a higher incidence of perforated appendix. METHODS This study used a retrospective chart review design. The site was a University Medical Center ED in Southern California with an average annual census of 35,000 staffed by residents in emergency medicine, medicine, family medicine, and faculty board certified in emergency medicine. Inclusion criteria were broad and encompassed all patients between the ages of 12 and 50 years of age seen in the ED between 1989 and 1994 with a final hospital discharge diagnosis of appendicitis. All ED and inpatient records along with operative reports and pathological reports were reviewed. Historical data points included: age; sex; time placed in an ED examination room; history of nausea, vomiting, diarrhea, and anorexia; history of pelvic inflammatory disease or abdominal surgery; and time of operative incision. Physical examination data included: temperature, blood pressure, pulse rate, abdominal tenderness, tenderness at McBurney’s point, psoas sign, rebound tenderness, cervical motion tenderness, adnexal tenderness, and cervical discharge. Ancillary information included: white blood cell count (WBC), abdominal radiographs, abdominal or pelvic ultrasound, abdominal computed tomography (CT), and laparoscopy. All data were entered into a database and analyzed using SASS software (SASS, Cury NC). Student’s t test was used
GUSS AND RICHARDS 䊏 MEN AND WOMEN WITH APPENDICITIS
to compare age, time to operation, percentage perforated, percentage undergoing abdominal radiograph, abdominal CT and laparoscopy. Chi-squared analysis was used to compare percentages of men and women with nausea, vomiting, diarrhea, anorexia, prior abdominal surgery, tenderness at McBurney’s point, psoas sign, and rebound tenderness. Statistical significance was set at P ⬍ .05 (two-tailed). This study was approved by our Institutional Review Board. RESULTS Two hundred and seventy-seven patients were identified of whom 196 met all study inclusion criteria. Thirty-nine charts were either incomplete or unavailable for review and 42 others were excluded. Eighteen were excluded because appendectomy was performed incidental to another operative procedure and not because of a presentation suggestive of appendicitis. Nineteen were excluded because of presentation from a site other than the ED. Three patients had percutaneous drainage of a periappendiceal abscess and an appendectomy was performed on an elective basis at a later date. Two patients were excluded because of factors that were felt to bias the management decisions: one patient was the spouse of a surgical resident and the other experienced an inordinate delay in operative management because of parental consent issues. Of the 196 patients comprising the study population, 113 were men with a mean age of 26.5 and 83 were women with a mean age of 26.4 (P ⫽ .93). Key clinical, historical, and physical examination parameters are summarized in Table 1. There was no statistically significant difference between men and women with respect to nausea, vomiting, anorexia, diarrhea, or rebound tenderness. Mean total WBC was 15,500/mm3 in men and 15,200/mm3 in women (P ⫽ .55). Abdominal computed tomography was performed on two men and one woman. The rates of other ancillary imaging tests are summarized in Figure 1. The mean time to operation was 477 minutes for males and 709 minutes for women (P ⫽ .02). Perforated appendix was identified in 44 men (38.7%) and 21 women (23.5%) (P ⫽ .002). Mean time to surgery in women with perforated appendix was 1,140 minutes versus 561 minutes for women without perforation (P ⫽ .0004). Mean time to surgery for men with perforated appendix was 487 minutes versus 472 minutes for those without perforation (P ⫽ .84). These data are summarized in Figure 2. TABLE 1.
Characteristics of Study Patients
Age (years) Temperature (F) WBC (1000/mm3) Nausea (%) Vomiting (%) Diarrhea (%) Anorexia (%) Rebound Tenderness (%)
Male N ⫽ 113
Female N ⫽ 83
P
26.5 99.5 15.5 79.6% 66.1% 22.0% 78.5% 62.5%
26.4 99.1 15.2 86.6% 68.3% 21.0% 74.6% 52.0%
.93 .12 .55 .20 .74 .88 .57 .16
373
DISCUSSION In the cohort of patients studied, the time from presentation to the ED to operative intervention was 48% longer in women than men, supporting part one of the study hypothesis. This difference is even more dramatic when comparing the subgroup of patients with perforation, 1,140 minutes for women and 487 minutes for men. The delay in operative intervention could not be explained by differences in clinical history or findings on physical examination at the time of initial evaluation. Delay in women might be explained, in part, by the higher rates of use of diagnostic imaging tests such as abdominal or pelvic ultrasound and abdominal CT. The reasons for this are speculative but likely related to the broader range of diagnostic considerations in women. Part two of the study hypothesis is rejected by this investigation, as the increased time to operative intervention in women compared with men was not associated with an increased rate of perforated appendix. This finding is difficult to explain considering that women with perforation had a much greater mean delay in operative intervention than women without perforation (1,140 minutes versus 561 minutes). This study did not permit determination of time from symptom onset to surgical intervention. If women tended to present earlier after symptom onset than men, the actual time from symptom onset to surgical intervention might have been shorter for women. If future study were to substantiate such a pattern, it would offer some explanation for the lower perforation rate encountered in women. An alternative explanation for the observed perforation rates would require some gender-based difference in the inflammatory response that results in an increased risk of perforation in men relative to women. The concept that right lower quadrant pain in women of childbearing age is a more complex clinical problem than it is in men is not novel. Women have historically had higher rates of negative laparotomy.1,3 Rothrock reported on 174 nonpregnant women with appendicitis and noted that 33% were misdiagnosed.12 Anderson reported decreased diagnostic accuracy for appendicitis among women, particularly in the third decade of life.5 The need for improved diagnostic testing in the evaluation of patients with appendicitis is suggested by this study both from the perspective of the delay encountered in the women as well as the extremely high perforation rate in men. A variety of approaches have been investigated including ultrasound, helical CT, WBC scanning, clinical scoring systems, and neural networks.13-21 A recent study using helical CT scanning with rectal contrast reported a diagnostic accuracy of 98%.20,21 Laparoscopy has been suggested as a strategy to reduce the rate of negative laparotomy and the time delay to final diagnosis.22 Although this approach is likely to reduce the rate of negative laparotomy, it is still an invasive procedure with significant cost and potential morbidity and would probably be associated with a high rate of negative laparoscopy. There are several limitations to this study. The retrospective design compromised the ability to reliably collect all data points resulting in the elimination of many cases. This
374
AMERICAN JOURNAL OF EMERGENCY MEDICINE 䊏 Volume 18, Number 4 䊏 July 2000
FIGURE 1. Diagnostic testing. e male, 䊏 female.
particular study focused on only those patients with surgically confirmed appendicitis and did not consider all patients in whom the diagnosis of appendicitis was considered. As a result we cannot comment on the rates of false-positive laparotomy, or determine if there are important differences between men and women in this regard. Finally, the gender differences in the time to surgery identified in this study may be peculiar to this institution and to the ED setting and thereby not applicable to other locales.
FIGURE 2. Time to operation. e male, 䊏 female.
CONCLUSION Compared with men, women presenting to the ED with a final hospital discharge diagnosis of appendicitis are associated with a significantly longer delay in operative intervention. Despite this delay, women have a significantly lower rate of perforated appendix. The authors thank Marian Jasek for her thoughtful review and assistance with the preparation of this manuscript.
GUSS AND RICHARDS 䊏 MEN AND WOMEN WITH APPENDICITIS
REFERENCES 1. Addiss DG, Shaffer N, Fowler BS, et al: The epidemiology of appendicitis and appendectomy in the United States. Am J Epidemiol 1990;132:910-925 2. Hale DA, Molloy M, Pearl RH, et al: Appendectomy: A contemporary appraisal. Ann Surg 1997;225:252-261 3. Rogers H, Faxon HH: A statistical study of six hundred and seventy one cases of appendicael periotnitis. N Engl J Med 1942;226: 707-717 4. Pieper R, Kager L, Nasman P: Acute appendicitis: A clinical study of 1018 cases of emergency appendectomy. Acta Chir Scand 1982;148:51-62 5. Anderson RE, Ilugander A, Thulin AJ: Diagnostic accuracy and perforation rate in appendicitis: Association with age and sex of the patient with appendectomy rate. Eur J Surg 1992;158:37-41 6. Lewis FR, Holcroft JW, Boey J, et al: Appendicitis: A critical review of diagnosis and treatment in 1000 cases. Arch Surg 1975;110: 677-684 7. Greenfield RH, Henneman PL: Disorders of the small intestine, in Rosen P (ed): Emergency Medicine Concepts and Clinical Practice. St Louis, MO, Mosby, 1998, pp 2005-2022 8. Trautlein J, Lambert R, Miller J: Malpractice in the emergency department—Review of 200 cases. Ann Emerg Med 1984;13:709711 9. Rusnak R, Borer J, Fastow J: Misdiagnosis of acute appendicitis: Common features discovered in cases after litigation. Am J Emerg Med 1994;12:397-402 10. Migraine S, Atri M, Bret PM, et al: Spontaneously resolving acute appendicitis: Clinical and sonographic documentation. Radiology 1997;205:55-58
375
11. Barber M, McLaren J, Rainey J: Recurrent appendicitis. Br J Surg 1997;84:110-112 12. Rothrock SG, Green SM, Dobson M, et al: Misdiagnosis of appendicitis in nonpregnant women of childbearing age. J Emerg Med 1995;13:1-8 13. Zeidan BS, Wasser T, Nicholas GG: Ultrasonography in the diagnosis of acute appendicitis. J R Coll Surg Edinb 1997;42:24-26 14. Foley CR, Latimer RG, Rimkus DS: Detection of acute appendicitis by technetium 99 HMPAO scanning. Am Surg 1992;58: 761-765 15. Lane MJ, Katz DS, Ross BA, et al: Unenhanced helical CT for suspected acute appendicitis. Am J Roentgenol 1997;168:405-409 16. Teicher I, Landa B, Cohen M, et al: Scoring system to aid in diagnosis of appendicitis. Ann Surg 1983;198:753-759 17. Eriksson S: Acute appendicitis—Ways to improve diagnostic accuracy. Eur J Surg 1996;162:435-442 18. Edwards FH, Davies RS: Use of bayesian algorithm in the computer-assisted diagnosis of appendicitis. Surg Gynecol Obstet 1984;158:219-222 19. Alvarado A: A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med 1986;15:557-564 20. Rao P, Rhea J, Novelline R, et al: Helical CT combined with contrast material administered only through the colon for imaging of suspected appendicitis. Am J Roentgenol 1997;169:1275-1280 21. Rao P, Rhea J, Novelline R, et al: Helical CT technique for the diagnosis of appendicitis: Prospective evaluation of a focused appendix CT examination. Radiology 1997;139-144 22. Deutsch A, Zelikovsky A, Reiss R: Laparoscopy in the prevention of unnecessary appendectomies: A prospective study. Br J Surg 1982;69:336-337