Pediatric Appendicitis Score (PAS)

About the PAS

The Pediatric Appendicitis Score is built on variables that have showed statistical significance for acute appendicitis and can be easily derived from patient history, physical and laboratory data:

PAS stratifies patients into three risk groups (high, equivocal and low risk):

Scores ≤3: “Appendicitis diagnosis unlikely”

Scores 4 – 6: “Score does not rule in or out appendicitis diagnosis – consider employing imaging and/or surgical consult.”

Scores ≥ 7: “Appendicitis diagnosis likely”

Pediatric patients who score less than 4 points are at low likelihood of suffering from acute appendicitis and the clinician should consider other causes of acute abdominal pain.

In the absence of the following (absence of RLQ pain, absence of pain with walking or coughing) and an ANC of less than 6,750, the score has a 95% negative predictive value. Caution and clinical gestalt is to be applied as patients in the low risk group do not have a zero risk.

Pediatric patients who score between 4 and 6 points are in the equivocal risk group (acute appendicitis cannot be ruled in or out) hence can benefit from imaging (ultrasound or MRI) and if findings are inconclusive, clinical consult.

Pediatric patients with a PAS greater than 6 should go straight to surgical consult.

About the original study

The Pediatric Appendicitis Score was developed by Samuel et al. in 2002, following a 5-year study on a cohort of 1,170 pediatric patients aged 4 to 15 years, with abdominal pain presentation.

734 of the subjects were subsequently diagnosed with appendicitis. Multiple linear logistic regression analysis of all clinical and investigative parameters was performed for a model comprising 8 variables to form a diagnostic score. See below the diagnostic index of each of the 8 variables:

■ (0.96) Right lower quadrant (RLQ) tenderness to cough, percussion, or hopping;

■ (0.88) Anorexia;

■ (0.87) Fever (temp ≥38.0ºC/100.4ºF);

■ (0.86) Nausea or vomiting;

■ (0.84) Tenderness over right iliac fossa;

■ (0.81) Leukocytosis (WBC ≥10,000);

■ (0.80) Neutrophilia (ANC >7,500);

■ (0.80) Migration of pain to RLQ.

6 of the variables are assigned 1 point if present whilst “Right lower quadrant (RLQ) tenderness to cough, percussion, or hopping” and “Tenderness over right iliac fossa” are assigned 2 points.

PAS alone was found to have a Sensitivity of 80% and a Specificity of 70%. PAS & Ultrasound (for scores 4 – 6) was found to have a Sensitivity of 92% and a Specificity of 95%.

The pediatric appendicitis score has been validated in multicenter studies.

References

Original reference

Samuel M. Pediatric Appendicitis Score. Journal of Pediatric Surgery, Vol 37,No 6 (June),2002: pp 877-881.

Validation

Goldman RD. The Paediatric Appendicitis Score (PAS) was useful in children with acute abdominal pain. Evid Based Med. 2009; 14:26

Kharbanda, AB. Validation and Refinement of a Prediction Rule to Identify Children at Low Risk for Acute Appendicitis. Arch Pediatr Adolesc Med. 2012; 166(8):738-744.

Other references

Saucier A, Huang EY, Emeremni CA, Pershad J. Prospective evaluation of a clinical pathway for suspected appendicitis. Pediatrics. 2014; 133(1):e88-95

Kulik DM, Uleryk EM, Maguire JL. Does this child have appendicitis? A systematic review of clinical prediction rules for children with acute abdominal pain. J Clin Epidemiol. 2013; 66(1):95-104.