I. How to Use

When to Use

Use in cases of suspected appendicitis in pediatric patients (< 18 years old).

Pearls / Pitfalls

The Pediatric Appendicitis Score (PAS) predicts the likelihood of appendicitis in pediatric patients (3-18 years old) with abdominal pain of ≤4 days duration.

The PAS should NOT be used in patients with known GI disease (eg. inflammatory bowel disease), pregnancy, or in patients with a history of previous abdominal surgeries.

Acute appendicitis can present in a wide variety of ways in children, particularly in younger ages. Younger children may have difficulty fully explaining their pain, or in differentiating abdominal pain from nausea. Signs of peritonitis may be absent, especially early on in the clinical course. The PAS should be used alongside clinical gestalt and should not be used in isolation to determine whether the diagnosis is present.

Why Use

The Pediatric Appendicitis Score has been validated in multicenter studies.

The PAS may be as good as clinician gestalt at identifying patients at low risk for appendicitis versus those with appendicitis. The score can help determine the need for surgical consultation or imaging.

II. Next Steps

Advice

For patients who are not low risk, next steps include checking NPO status, administering IV fluids, analgesics as needed, and imaging or surgical consultation.

In real life practice, imaging is often obtained simultaneously with labs for the evaluation of appendicitis. The PAS can help to determine whether further imaging is needed in cases of an equivocal ultrasound, for example. However a “low risk” score does not completely rule out appendicitis.

Use caution in evaluating for appendicitis in younger age groups (age < 5 years), as their ability to articulate their symptoms and their overall clinical presentation may vary greatly.

Management

Low Risk PAS (<4)

  • Low likelihood of acute appendicitis; imaging may not be warranted.

  • The score has a higher negative predictive value (95%) when patients do not have right lower quadrant pain, do not have pain with walking, jumping, or coughing, and have an ANC < 6,750.

  • Consider other causes of acute abdominal pain.

Equivocal PAS (4-6)

  • Imaging can be helpful for this subgroup of patients. Typically, ultrasound is the first study of choice for pediatric patients to reduce the risk of radiation exposure. When not available, or if other imaging results are equivocal, cross sectional imaging such as CT abdomen/pelvis with IV contrast can be considered.

  • Consider surgical consultation for patients with equivocal scores and imaging where the appendix cannot be visualized, where available.

High Risk PAS (>6)

  • Consider surgical consultation prior to or alongside imaging studies for these patients.

  • Imaging may still be pursued, but patients should only undergo ultrasound prior to a surgical consult.

Critical Actions

Acute appendicitis can cause severe illness and sepsis. In cases of unstable patients with suspected sepsis, regardless of cause, empiric antibiotic and fluid resuscitation should not be delayed in order to obtain imaging studies or diagnostic tests.

Patients in the low risk group according to the PAS do not have zero risk. In other words, a low risk score does not completely rule out the diagnosis of acute appendicitis. Use clinical discretion if imaging or surgical consultation may aid in diagnosis.

Other diagnoses such as mesenteric adenitis or ovarian torsion may present similarly to acute appendicitis. The PAS should be used in conjunction with clinical assessment to aid in determining further evaluation or consultation for suspected pediatric appendicitis.

III. Evidence

Evidence Appraisal

The Pediatric Appendicitis Score was developed by Madan Samuel in 2002 in a prospective cohort study of 1,170 patients ages 4 to 15 years with abdominal pain.

Clinical history, physical exam, and laboratory data were analyzed to find 8 variables that showed statistical significance for acute appendicitis and were included as part of the final 10 point scale. The presence of anorexia, fever (>38.0C), nausea or vomiting, leukocytosis (WBC > 10,000), neutrophilia (ANC > 7,500), and pain migration to the right lower quadrant are each worth one point toward the total score. The presence of right iliac fossa tenderness is worth two points, as is the presence of pain with cough, jumping, or percussion (two points added if any of the above are present; see table in “Facts & Figures”).

It has since been validated in external multicenter studies, including in a broader cohort with ages ranging from 1-17 years (Goldman et al. in J Pediatr, 2008). Shah and colleagues developed a diagnostic algorithm in 2016 which they used prospectively in 840 patients, 267 of which were ultimately diagnosed with appendicitis. The algorithm was found to be 98.6% sensitive and 94.4% specific, with a decrease in utilization of CT from 75.4% to 24.2%.

There are multiple other scales that aim to predict the risk of appendicitis in children, none of which have reliably outperformed the others. In a head-to-head comparison of the PAS and the Alvarado score, Schneider et al. found that the scores performed similarly in terms of their test characteristics, but that neither had high enough sensitivity and specificity to determine the need for surgery independent of surgical evaluation or definitive imaging. Other scores include the Pediatric Appendicitis Risk Calculator (pARC) and the RIPASA score.

Formula

Addition of the selected points (below).

Facts & Figures

Variable Points
Right lower quadrant (RLQ) tenderness to cough, percussion, or hopping 2
Anorexia 1
Fever (temp ≥38.0ºC/100.4ºF) 1
Nausea or vomiting 1
Tenderness over right iliac fossa 2
Leukocytosis (WBC ≥10,000) 1
Neutrophilia (ANC >7,500) 1
Migration of pain to RLQ 1

Literature

Original/Primary

https://com-emergency.sites.medinfo.ufl.edu/files/2013/02/Pediatric-Appendicitis-Score.pdf

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

Validation

https://www.sciencedirect.com/science/article/pii/S0022347608000735

Goldman RD, Carter S, Stephens D, et al. Prospective Validation of the Pediatric Appendicitis Score. J Pediatr 2008;153(2):278-282.

http://ebm.bmj.com/content/14/1/26.extract

Goldman RD. The Paediatric Appendicitis Score (PAS) was useful in children with acute abdominal pain. Evid Based Med 2009;14:26 doi:10.1136/ebm.14.1.26

http://jamanetwork.com/journals/jamapediatrics/fullarticle/1263344

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. doi:10.1001/archpediatrics.2012.490

Other References

https://www.ncbi.nlm.nih.gov/pubmed/27433918

Shah SR, Sinclair KA, Theut SB, Johnson KM, Holcomb GW 3rd, St Peter SD. Computed Tomography Utilization for the Diagnosis of Acute Appendicitis in Children Decreases With a Diagnostic Algorithm. Ann Surg. 2016 Sep;264(3):474-81.

https://pubmed.ncbi.nlm.nih.gov/17383771/

Schneider C, Kharbanda A, Bachur R. Evaluating appendicitis scoring systems using a prospective pediatric cohort. Ann Emerg Med. 2007;49(6):778-784.e1. doi:10.1016/j.annemergmed.2006.12.016