Rashmi Damodaran

rashmi.damodaran@cambio.se

@ CambioCDS

To help determine need for advanced imaging such as formal ultrasound or CT and also, to identify low risk patients who can be observed in or discharged from the ED with follow up or return precautions.

Use in children ≥5 years old presenting to the emergency department or outpatient setting with acute abdominal pain (duration <96 hours). It uses 8 variables to calculate the pARC score in two different settings of Pediatric ED and Community setting (outpatient setting). The variables include; Age, gender, Duration of pain, ANC, Presence of pain with walking, Maximal tenderness in RLQ, Abdominal guarding, History of migration of pain to RLQ. Formulas: ANC = (neutrophil, % x WBC, cells x 10^3/µL) / 100 and If neutrophil count is not available, ANC = (-0.8783 + 1.1008 x √WBC, cells x 10^3/µL)^2. pARC Score (ED) = e^x / (1 + e^x) pARC Score (Community) = e^-0.615 + 1.1x / (1 + e^-0.615 + 1.1x) Where x = −8.6855 + addition of the assigned values to each of the variables. Variable Value Gender Female 0 Male 1.2780 Age Male >13 years or female >11 years 0 Female 3-7 years 0.3810 Female 8-11 years 0.6513 Male 3-7 years -0.6653 Male 8-13 years -0.0654 Duration of pain, hrs <24 0 24 to <48 0.4696 48 to 96 0.1003 >96 0 Unknown (defaults to <24 hrs) 0 ANC*, cells x 103/µL <14 1.7734 x √ANC >=14 6.6195 Presence of pain with walking No 0 Yes 1.0494 Maximal tenderness in RLQ No 0 Yes 1.1435 Abdominal guarding No 0 Yes 0.6736 History of migration of pain to RLQ No 0 Yes 0.4557 Interpretations: Pediatric ED setting: pARC Score (ED) Risk Group Clinical Recommendation ≤5% Ultra low Outpatient follow up appropriate if PCP evaluation available within 24 hrs; no diagnostic imaging required 6-15% Low Consider ED observation for 6 hrs for serial exams; if improved, ensure outpatient follow-up in 24 hrs; no imaging required 16-25% Low-moderate If patients symptoms <24 hrs, consider observation for 12 hrs; if not improved, obtain ultrasound and repeat CBC; if pain ≥24 hrs of symptoms, obtain ultrasound for evaluation 26-50% Moderate Ultrasound recommended as first line imaging; admit for observation if ultrasound equivocal 51-75% Moderate Ultrasound recommended as first line imaging; CT if ultrasound equivocal 76-90% Moderate-high Consult surgery; consider imaging based on surgery recommendations >90% High Consult surgery; imaging not required Community Setting: pARC Score(Community) Risk group <5% Very low 5-14% Low 15-84% Intermediate ≥85% High

Not recommended for children < 5 years old, as Appendicitis is relatively rare in children this age group, and is more likely to present with atypical features not captured by this calculator.

1. Kharbanda AB, Vazquez-Benitez G, Ballard DW, Vinson DR, Chettipally UK, Kene MV, et al. Development and Validation of a Novel Pediatric Appendicitis Risk Calculator (pARC). Pediatrics [Internet]. 2018 Apr;141(4). Available from: http://dx.doi.org/10.1542/peds.2017-2699 2. Cotton DM, Vinson DR, Vazquez-Benitez G, Margaret Warton E, Reed ME, Chettipally UK, et al. Validation of the Pediatric Appendicitis Risk Calculator (pARC) in a Community Emergency Department Setting [Internet]. Vol. 74, Annals of Emergency Medicine. 2019. p. 471–80. Available from: http://dx.doi.org/10.1016/j.annemergmed.2019.04.023

OBSERVATION.basic_demographic.v1, OBSERVATION.pediatric_appendicitis_risk_calculator.v0, OBSERVATION.lab_test-full_blood_count.v1