Novel scoring system using US findings holds promise in child acute appendicitis diagnosis

A new scoring system appears to be a good alternative to existing schemes, such as the Alvarado score, in quantifying the risk of complications and strength of recommendation for surgical intervention in child acute appendicitis, a Singapore study has shown.

“[T]his study proposed a newly developed scoring scheme [called POPs] that integrates inflammatory predictors and ultrasonographic (US) findings into a comprehensive score, allowing for effective risk stratification in paediatric cases of acute appendicitis, with a range of 0–20 risk points,” the researchers said. “Although further calibration would certainly be beneficial, the proposed scoring scheme is simple, as well as easy to understand, remember, and apply in the emergency room.”

Overall, 179 patients with suspected appendicitis who had undergone US examination were enrolled in this study. They were further categorized into confirmed appendicitis (n=101) and nonappendicitis (n=78) groups based on their medical evaluation and postsurgical histopathological results.

The appendix was visualized in 66 patients (65.3 percent) in the appendicitis group. In cases where the appendix was not visualized, the researchers examined any secondary inflammatory signs, which were found in 32 patients (31.7 percent). [Singapore Med J 2020;doi:10.11622/smedj.2020102]

Stepwise logistic regression showed the following significant risk factors for appendicitis: Blumberg’s sign, free fluid or collection, hyperaemia, noncompressible appendix, and an appendix diameter >7 mm. Using these inflammatory predictors and US findings, the researchers then developed the POPs-based diagnostic scheme, with an area under the receiving operating characteristic curve of 0.958 (95 percent confidence interval [CI], 0.929–0.986).

The visualization rate in this study was comparable to that of Mittal and colleagues, who found a lower rate of appendix visualization in hospitals where US examinations is less often conducted (25 percent) as compared to those where US was routinely employed in appendicitis diagnosis (56 percent). [Acad Emerg Med 2013;20:697-702]

In addition, a study by Trout and colleagues stressed the high false negative and false positive rates in US examinations. The current researchers suggested the involvement of experienced personnel and additional training to improve diagnostic performance. [Pediatr Radiol 2012;42:813-823]

“US findings have been used to enhance diagnosis methods of acute appendicitis in many studies, although a quantitative scoring system for suspected appendicitis in children is not yet available,” the researchers noted.

A study by Larson and colleagues, which evaluated the diagnostic accuracy of US of paediatric appendix among 1,357 examinations, reported a 96.8-percent accuracy of a five-category interpretive scheme. The current study, however, did not classify US findings into categories, but a discriminative power of US by area under the curve (0.807, 95 percent CI, 0.642–0.972) was found. [AJR Am J Roentgenol 2015;204:849-856]

“Diagnosis of acute appendicitis in children is difficult due to many factors, and the removal of a healthy appendix is associated with a greater risk of abdominal adhesions as compared to acute appendicitis,” the researchers said. “This is a hazard to be considered in contrast with an increasing rate of appendiceal perforation in delayed surgical interventions.” [Asian J Surg 2013;36:144-149]

However, surgery must not be delayed in paediatric patients with a high suspicion of appendicitis due to the high risk of perforation and further secondary complications, according to the researchers.