Appraisal of the modified Alvarado score for acute appendicitis in the adults

Mohamed I. Seleem and Ahmed M. Al-Hashemy

Keywords: Modified Alvarado Score, Acute Appendicitis, adult.

Abstract

Background

Decision making in cases of acute appedicitis may be difficult specially for junior surgeons. Radiological investigations do not appear to be helpful. In some studies the Modified Alvarado Scoring System (MASS) was helpful in minimizing unnecessary appendicectomies. The aim this study was to evaluate the sensitivity of MASS in the diagnosis of acute appendicitis in adults.

Patients and methods

All adult patients aged 16 years and above who were admitted with a provisional diagnosis of acute appendicitis into the Armed Forces Hospitals, Southern Region, Khamis Mushayt, KSA, over one year period were prospectively entered into the study. The study included 125 patients between the ages of 16 and 76 years. They were prospectively evaluated on admission using the Modified Alvarado Score(MAS) to determine whether or not they had acute appendicitis. The MAS was correlated with the operative and histopathological findings.

Results

110 patients (88%) had appendicectomies of which 30 patients (27.3%) had normal appendices on histopathology examination. Overall the MAS system showed a sensitivity of 53.8% and a specificity of 80%. For males the sensitivity was 56.4% and the specificity was 100%. For females the sensitivity and specificity were 48% and 62.5% respectively.

Conclusion

From the results, the MASS is not sufficiently sensitive adopted as a method of diagnosing of acute appendicitis in adults in our environment. Further requirements may be needed to improve its sensitivity and specificity.

Keywords: Modified Alvarado Score, acute appendicitis, adults

Introduction

The classical signs and symptoms of acute appendicitis were first reported by Fitz 1 in 1886. Since then it has remained the most common diagnosis for hospital admission requiring laparotomy.2,3 Approximately 6% of the population will suffer from acute appendicitis during their lifetime, therefore much effort has been directed toward early diagnosis and intervention.4 This effort has successfully lowered the mortality rate to less than 0.1% for non complicated appendicitis, 0.6% where there is gangrene, and 5% for perforated cases.4 The diagnosis of appendicitis can be difficult, occasionally taxing the diagnostic skills of even the most experienced surgeon. Equivocal cases usually require inpatient observation. This delay in diagnosis may increase the morbidity and costs. Attempts to increase the diagnostic accuracy in acute appendicitis have included computer aided diagnosis, imaging by ultrasonography, laparoscopy, and even radioactive isotope imaging.5,6,7,8 Various scoring systems have been devised to aid diagnosis.9,10,11 The Alvarado score was described in 1986 12and has been validated in adult surgical practice. This study was undertaken to evaluate the sensitivity of the MASS in adult patients with a diagnosis of acute appendicits admitted to our hospital.

Patients and Methods

One hundred and twenty five adult patients (76 male patients with mean age 28.57 years and 49 female patients with mean age 25.98 years) with a mean age of 27.1 ± 11.38 years (Range 16-76 years) admitted to the surgical department, Armed Forces Hospital over a one year period formed the bass of this study. At admission, all the patients were prospectively evaluated using the MASS to determine whether they had acute appendicitis or not. The scores were subsequently correlated with the clinical, operative and histopathological findings of the removed appendices.

The decision to apply the score is based on the following presentations, three symptoms, three signs and one investigation as shown in (Table- 1)13 The classic Alvarado Score included left shift of neutrophil maturation (score 1) yielding a total score of 10 but Kalan et al 13 omitted this parameter which is not routinely available in many laboratories, and produced a modified score. Patients with a score of 1-4 are considered unlikely to have acute appendicitis, those with a score of 5-6 have a possible diagnosis of acute appendicitis, not convincing enough to have urgent surgery, and those with score of 7-9 are regarded as probable acute appendicitis.

The MAS was recorded on the admission sheet and played no role in the management of the patients. The diagnosis of acute appendicitis was made clinically by the surgical on call team (Residents and Specialists). Abdominal ultrasonography was performed in 21 doubtful cases leading to the diagnosis of two cases each of right ovarian cyst, right iliac fossa mass respectively and one case of dilatation of the pelvicalcyeal system of right kidney. All patients were operated upon using clinical diagnosis.

Result

The operative finding in the 110 patients who underwent appendicectomies are summarised in (Table-2)

In 43 patients (34.4%) who were placed under observation, the MAS was re-assessed 6 hourly after admission. In 6 patients the MAS decreased from 7 to 3 and in 4 patients from 5 to 4 , however, in 4 patients MAS increased. In the remaining 29 patients, MAS remained unchanged.

Our data showed that clinical diagnostic accuracy was greater than MASS (Table 3).

Our false positive appendicectomy rate was 27.3% (There were three patients with clear intra-operative pathology, one patient had salpingitis, one patient had ovarian cyst and one patient had ceacal abscess). Utilizing the Modified Alvarado Score, 52 patients had a score ³ 7 of whom 43 had confirmed appendicitis, and 73 patients had score < 7 of whom 48 had confirmed appendicitis by histopathology. The overall sensitivity of the MASS was 53.8% and its specificity 80% (Table-4).

Discussion

The diagnosis of acute appendicitis continues to be difficult due to the variable presentation of the disease and the lack of reliable diagnostic test. Although there has been some improvement in the diagnosis of acute appendicitis over the past several decades, the percentage of normal appendices reported in various series varies from 8 to 33%.14-16 Clinical scoring systems have proved useful in the management of number of surgical conditions. In the past few years various scores have been developed to aid the diagnosis of acute appendicitis.17 Although many diagnostic scores have been advocated, most are complex and difficult to implement in the clinical situation.17 The Alvarado score, is a simple scoring system that can be instituted easily.12 In a prospective study of 215 adults and children in Cardiff, use of the Alvarado score decreased an unusually high false-positive appendicectomy rate of 44% to14%.18 Fenyo 11, reported in one study a sensitivity of 90.2% and specificity of 91.4% and others reportedand a sensitivity of 73%, specificity of 87% with negative laparotomy rate of 17.5%. 19 To be useful, a scoring system must be both sensitive and specific. The modified Alvarado score proved to be effective in one study in adult patients with acute appendicitis13 but in another study was not successful in paediatric age group.20 Our study demonstrates that modified Alvarado score applied to all adult paitients is substantially inferior to our current clinical acumen in the diagnosis of acute appendicitis in adults. In sub group analysis however, we do note that all 31 males with a score of 7 or more did in fact have appendicitis but the MASS was of no predictive value in males scoring less than 7 and none at all in females regardless of the score.

Conclusion

From our data, the MASS was not found to be a useful complementary method in the diagnosis of suspected case of acute appendicitis in adult patients. Further requirements may be needed to improve its sensitivity and specificity.

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