Pakistan Journal of Medical Sciences

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ISSN 1681-715X

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ORIGINAL ARTICLE

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Volume 25

January - March 2009

Number  1


 

Abstract
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Diagnostic Accuracy of Alvarado Score in
the Diagnosis of acute Appendicitis

Ayaz Ahmed Memon1, Lubna Mushtaque Vohra2,
Tanvir Khaliq3, Ahmer Adnan Lehri4

ABSTRACT

Objective: To determine the diagnostic accuracy of Alvarado score in the diagnosis of acute appendicitis.

Methodology: Study was conducted in Surgical Ward 5, Pakistan Institute of Medical Sciences Islamabad. Duration of study was Six month from December 2006 to June 2007. Hundred consecutive patients which presented to our surgical team with acute appendicitis were assessed prospectively using Alvarado score. They were given specific scores according to the variable and divided into two groups, group one (score >7) group two (score <7). All patients were operated irrespective of score, if clinical diagnosis of acute appendicitis was made. Postoperatively, diagnosis was confirmed by histopathology report. Validity of scoring system was assessed by calculating sensitivity, specificity and positive predictive value.

Results: Total 100 patients were included in the study, which included 65 males and 35 females, at score >7, appendicitis was confirmed in 53/54 patients, while at scores <7 appendicitis was confirmed in 38/46 patients. The sensitivity was 58.2%, specificity was 88.9% and positive predictive value was 98.1%.

Conclusion: Clinical experience remains of major importance in diagnosing acute appendicitis. The Alvarado score is a simple, easy scoring system at both end of scale.

KEY WORDS: Appendicitis, Alvarado score, Accuracy.

Pak J Med Sci    January - March 2009    Vol. 25 No. 1    118-121

How to cite this article:

Ahmed AM, Vohra LM, Khaliq T, Lehri AA. Diagnostic Accuracy of Alvarado Score in the Diagnosis of acute Appendicitis. Pak J Med Sci 2009;25(1):118-121.


1. Dr. Ayaz Ahmed Memon, MCPS, FCPS
P.G Trainee,
2. Dr. Lubna Mushtaque Vohra, MCPS, FCPS
Medical Officer,
3. Dr, Tanvir Khaliq, FCPS, FRCS
Associate Professor,
4. Dr. Ahmer Adnan Lehri, MBBS
House Officer
1-4: Pakistan Institute of Medical Sciences (PIMS),
Islamabad – Pakistan.

Correspondence

Dr. Ayaz Ahmed Memon,
P.G Trainee,
Department of Surgery, Unit IV,
Pakistan Institute of Medical Sciences,
Islamabad – Pakistan.
Email: memonayaz2002@yahoo.com

* Received for Publication: October 28, 2008
* Accepted for Publication : January 31, 2009


INTRODUCTION

Over a hundred years have passed since Mc Burney reported his study on acute appendicitis in eight patients with emphasis on early appendicectomy.1 It is common surgical condition with lifetime prevalence of 7-8%.2 A million of people annually comes to accident and emergency or worldwide hospitals. Although abdominal surgeons have been encountering the acute appendicitis for more than 100 years, prompt diagnosis is elusive in order to reduce morbidity and to avoid serious complication.3

Although patients with acute appendicitis often present with a characteristic symptoms and physical findings, atypical presentation are common and accurate identification of patient who required immediate surgery as opposed to those who will benefit from active observation is not always easy. Many times age and gender confounds the clinical picture, like in premenopausal female diagnostic considerations are broader, even in elderly patient diagnosis is a challenge, because of delay in seeking medical care or difficulty in obtaining a proper medical history and a need of accurate physical examination.3

Delay in diagnosis and treatment of appendicitis are associated with increased rate of morbidity and mortality. So to avoid this problem surgeons have a traditional approach for early intervention even in the absence of definitive diagnosis.4 Negative appendicectomy rate of 15-40% has been reported in literature and many surgeons would accept this rate as inevitable.5,6

Differential diagnosis and management of patient presenting with right iliac fossa pain is a continuing surgical challenge. Imaging modalities might improve diagnostic accuracy, however their use has not been shown to improve the outcome in acute appendicitis when compared to clinical judgement.7

Several scoring systems have been devised to increase the sensitivity and specificity in diagnosis of acute appendicitis. They help to reduce the rate of negative appendicectomy.8-10 Alvarado score in this context is a simple, easy to apply, a cheap tool and an effective mean of stratifying patients according to the risk of acute appendicitis. It is based on history, clinical examination, and few laboratory investigations, which helps to reduce negative appendicectomy rate and improved patient quality of care.11

METHODOLOGY

Study was conducted at ward-V Department of General Surgery, Pakistan Institute of Medical Sciences Islamabad from December 2006 to June 2007. One hundred patients were included in the study after taking informed consent. Patients with the diagnosis of acute appendicitis were admitted in the ward and their Alvarado score (Table-I) were calculated. A score of >7 was indicating acute appendicitis and a score below this level meant normal appendix but the decision to undergo surgery was purely on clinical grounds. Patients were operated by conventional method of appendicectomy. Diagnosis was confirmed by histopathology findings, which reveals in early acute appendicitis scant neutrophil exudation throughout the mucosa, submucosa and muscularis, Congestion of subserosal vessels, perivascular neutrophil emigration. The Alvarado score was correlated with the histopathological findings of the removed appendix (Table-II). All data was analysed by SPSS version 10.

RESULTS

Total one hudnred patients were included in the study, which included 65% male and 35% female. Mean age of the patient was 24.80 ± 9 years (Range 13-55). Most of them were in 10-20 years age group i.e. 43%.

There were 54 patients with Alvarado score >7, and 46 patients with score <7. Peroperative observation revealed that 97% of patients had acutely inflamed appendix. On histopathological confirmation 98.1% of patients had acutely inflamed appendix with Alvarado score >7, while 83% with score <7.

The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 58.2%, 88.9%, 98.1%, 17.4% and 61% respectively. (Table-III)

DISCUSSION

Alvarado score is a simple non-invasive diagnostic procedure, which is reliable, safe, repeatable and economical, easy and can be used, in emergency setting, without expensive and complicated supportive diagnostic tools. There was no statistical difference between emergency medicine resident using the Alvarado score and general surgery resident in terms of suspecting the diagnosis of acute appendicitis when using Alvarado score.6,10-14

Several studies validated the Alvarado score but on the other hand many studies recommend taking cut-off point at 4 or 6.15,16 In this study, 98% of patients with Alvarado score >7 have evidence of acute appendicitis on histopathology with positive predictive value of 98.1% and sensitivity of 58% which is comparable to study conducted by Ahmed et al17 giving sensitivity of 53.8%. It clearly indicates that high score may be used as an aid in deciding the need for immediate appendicectomy especially for junior surgeons. Matija et al3 study documented 100% positive predictive value of score >7 in the diagnosis of acute appendicitis in females. Hizbullah et al12 study documented positive predictive value of 85% at score >7. But in another study conducted by Ikramullah et al11 positive predictive value was found to be 83.5% in adults. Another study conducted by Pruekprasert et al18 reported sensitivity of >7 score of 79% while those who were operated upon based on surgeons clinical experience the sensitivity was found to be 96% while in our study 91% sensitivity was seen on the basis of clinical experience irrespective of score.

In our study negative appendicectomy at score >7 was 1.8% i.e. only one patient with >7 had non-inflamed appendix which is comparable to Matija et al3 study who revealed no case of removal of normal appendix at score >7, while Ikramullah et al11 reported it 15.6%. In another study conducted by Khalid et al19 negative appendicectomy rate was 11%. In our study, very low negative appendicectomy rate at score >7 could be due to referred patients who were treated in primary care hospitals initially and then referred with high suspicion of acute appendicitis after 1-2 days of onset of symptoms.

The only case in our study, who had normal appendix at score >7 was a female. Literature support this observation that in female additional investigations are needed to support diagnosis, as Michael et al20 combined the Alvarado score with selective laparoscopy in adult female to increase the diagnostic accuracy and to avoid negative appendicectomy. In his study it was 0% at score >7. However, Ajaz et al21 reported the use of Alvarado score with positive predictive value at score of >7 of 80% as it had a very high negative appendicectomy rate in female giving sensitivity of 61% in female.

However in our study population, those who had score <7 but proceeded to surgery purely on the basis of surgeon’s decision have evidence of acute appendicitis on histopathology in 82% with negative appendectomy rate of 17%. Most of these patients fall at score >5 while all those at score 3 or 4 have normal appendix. Ajaz et al21 reported the positive predictive value 66.6% in case of score <7, but another study conducted by Arsalan et al15 gives figures of negative appendicectomy of 5% at score >4 with positive predictive value of 94%. However, in our study increased number of histopathological diagnosis of acute appendicitis, at score <7 may be due to the fact that Pakistan Institute of Medical Sciences is a tertiary care centre, where patients are generally referred from different centres and it is a common routine practice in our setup that antibiotics are used injudiciously and these drugs may alter the disease process and clinical presentation leads to low Alvarado score.

CONCLUSION

Clinical findings and experience remains of major importance in diagnosing acute appendicitis. Alvarado score is a useful tool in the diagnosis of acute appendicitis especially at both end of scale. The diagnosis in patients with equivocal features can be difficult. In our sub population, Alvarado scoring cut off should be >5, which readily increases the sensitivity and accuracy of Alvarado score in diagnosing acute appendicitis. Different cut off point may be considered for different sub population.

REFERENCE

1. McBurney C. Experience with early operative interference in. cases of disease of the vermiform appendix. NY Med J 1889;50:676-84.

2. Christian F, Christian GP. A simple scoring system to reduce the negative appendicectomy rate. Ann R Coll Surg Engl 1992;74:281-5.

3. Horzic M, Salamon A, Kopljar M, Skupnjak M, Cupurdija K, Vanjak D. Analysis of Scores in Diagnosis of Acute Appendicitis in Women. Coll Antropol 2005;29:133-8.

4. Pittman-Waller VA, Myers JG, Stewart RM, Dent DL, Page CP, Gray GA, et al. Appendicitis: why so complicated? Analysis of 5755 consecutive appendectomies. Am Surg 2000;66:548-54.

5. Bhopal FG, Khan JS, Iqbal M. Surgical audit of acute appendicitis. J Coll Physicians Surg Pak 1999;9:223-6.

6. Talwar S, Talwar R, Prasad P. Continuing diagnostic challenge of acute appendicitis: evaluation through modified alvarado score: comment. Aust N Z J Surg 1999;69:821-2.

7. McDonald GP, Pendarvis DP, Wilmoth R, Daley BJ. Influence of preoperative computed tomography on patients undergoing appendectomy. Am Surg 2001;67:1017-21.

8. Fenyo G, Lindberg G, Blind P, Enochsson L, Oberg A. Diagnostic decision support in suspected acute appendicitis: validation of a simplified scoring system. Eur J Surg 1997;163:831-8.

9. Alvarado A. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med 1986;15:557-64.

10. Eskelinen M, Ikonen J, Lipponen P. Sex-specific diagnostic scores for acute appendicitis. Scand J Gastroenterol 1994;29:59-66.

11. Khan I, Rehman A. Application of Alvarado scoring system in diagnosis of acute appendicitis. J Ayub Med Coll Abottabad 2005;17:41-4.

12. Jan H, Khan J. Evaluation of modified Alvarado score in the diagnosis of acute appendicitis. Pak J Surg 2007;23:248-50.

13. Denizbasi A, Unluer EE. The role of the emergency medicine resident using the Alvarado score in the diagnosis of acute appendicitis compared with the general surgery resident. Eur J Emerg Med 2003;10:296-301.

14. Hsiao KH, Lin LH, Chen DF. Application of the MANTRELS scoring system in the diagnosis of acute appendicitis in children. Acta Paediatr Taiwan 2005;46:128-31.

15. Bukhari SAH, Rana SH. Alvarado Score: A new approach to Acute Appendicitis. Pak Armed Forces Med J 2002;52:47-50.

16. Shrivastava UK, Gupta A, Sharma D. Evaluation of the Alvarado score in the diagnosis of acute appendicitis. Trop Gastroenterol 2004;25(4):184-6.

17. AlHashemy AM, Saleem MI. Appraisal of the modified Alvarado score for acute appendicitis in adults. Saudi Med J 2004;25:1229-31.

18. Pruekprasert P, Maipang T, Geater A, Apakupakul N, Ksuntigij P. Accuracy in diagnosis of acute appendicitis by comparing serum C-reactive protein measurements, Alvarado score and clinical impression of surgeons. J Med Assoc Thai 2004;87:296-303.

19. Malik KA, Sheikh MR. Role of modified Alvarado score in acute appendicitis. Pak J Surg 2007;23:251-4.

20. Lamparelli MJ, Hoque HM, Pogson CJ, Ball AB. A prospective evaluation of the combined use of the modified Alvarado score with selective laparoscopy in adult females in the management of suspected appendicitis. Ann R Coll Surg Engl 2000;82:192-5.

21. Malik AA, Wani NA. Continuing diagnostic challenge of acute appendicitis: Evaluation through modified Alvarado score. Aust N Z J Surg 1998;68:504-5.


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