| dc.description.abstract | Background: Acute appendicitis remains the most common indication for surgical intervention in acute abdomen. The negative appendicectomy rate is 25% at KNH according to a recent study.'! Diagnosis of acute appendicitis continues to be a challenge. This is especially so for the less experienced clinicians who are the majority in our setup. There is need for an easily available and cost effective protocol to aid the clinician in making an accurate diagnosis of acute appendicitis.
Objective: To determine the diagnostic accuracy of a protocol that combined modified Alvarado scoring and ultrasonography for equivocal cases in acute appendicitis at Kenyatta National Hospital.
Design: A prospective observational study
Setting: KNH accident and emergency and general surgery departments
Patients and methods: Patients presenting with suspected acute appendicitis were scored using the modified Alvarado scoring system. Patients who scored 7 and above proceeded to surgery while those who scored the equivocal range of 4 to 6 underwent ultrasound scanning for suspected appendicitis as described by puylaert.76 Confirmation of appendicitis was based on histopathology as the reference standard.
Results: A total of 100 patients were recruited in the study over a period of 8 months from July 2011 to March 2012. The ratio of male to female patients was 1.2:1. The range of ages of presentation was 7 to 55 years with a median age of 26.The mean age was 27.9 years with a standard deviation of 11.4. Fifty four patients had a modified Alvarado score of 7 and above while 46 patients scored between 4 and 6 and underwent ultrasonography. The area under the curve for the receiver operating curves was 0.60 and 0.58 for ultrasonography and MAS plus ultrasonography respectively. There was no statistical difference between the PPV of MAS between 4 and 6 and of ultrasonography in the equivocal cases. Ultrasonography had sensitivity, speciflcitv, PPV and NPV values of 93.50/0(95% Cl,78.5-99.2), 26.7%(95% Cl,7.8-55.1), 72.5%(95% Cl,56.1-85.3) and 66.70/0(95% Cl,22.2-95.6) respectively. The overall sensitivity, spedticitv, PPV and NPV of the protocol was 97.5%(95%Cl,91.2-99.7),19%(95% Cl,5.4-41.9),81.9%(950/0 Cl,72.6-89.1) and NPV 66.7%(95% Cl,22.2-95.7) respectively. The crude negative appendicectomy rate for the series was 21%. The calculated negative appendicectomy rate with the protocol factored in was 18%. The protocol had a missed appendicitis diagnosis rate of 2%. The overall accuracy of the protocol in the diagnosis of acute appendicitis was 81 % .
Conclusions: The diagnosis of acute appendicitis is first and foremost a clinical diagnosis with scoring systems and imaging being necessary adjuncts in the equivocal cases. The use of a protocol based on modified Alvarado score and ultrasonography is a useful and easily available tool in the diagnosis of acute appendicitis. The protocol can aid the clinician to 'rule-in' appendicitis. However, the specificity of the protocol is still low in the KNH setting and may largely be dependent on the learning curve of ultrasonography technique. | en_US |
