Paediatric appendicitis – Clinical decision rules


 An eight-year old male was admitted to the Emergency Department (ED) with a 6-hour history of severe peri-umbilical abdominal pain. He had one episode of vomiting, complained of nausea, and an absence of appetite (anorexia) he has also described one episode of ‘loose’ stool.

Additionally, the child was known to have recovered from a viral illness in the last two-weeks.

Examination revealed low-grade pyrexia of 37.9 degrees centigrade, with accompanying abdominal tenderness in the right lower quadrant. No umbilical or inguinal herniation was found and testicular examination was unremarkable.

Initial non-invasive investigation by urinalysis excluded urinary tract infection.

So What?

Appendicitis in children can be difficult to diagnose not least because it is mimicked by Mesenteric Adenitis, a non-surgical viral induced lymphadenitis of the mesentery.

The Alvarado Score and Paediatric Appendicitis Score (PAS) assist in the risk stratification of patients attending the ED with suspected appendicitis (Samuel, 2002; Ohle et al, 2011).


Feature Alvarado Score PAS Score
Migration of pain 1 1
Anorexia 1 1
Nausea 1 1
Tenderness in the right lower quadrant 2 2
Rebound pain 1
Elevated temperature 1 1
Leucocytosis 2 1
Shift of white cell count to the left 1 1
Coughing/hopping/percussion pain 2
Total = 10 10

An Alvarado score score of 4 or less is highly sensitive as a “rule-out” criteria (99% sensitive) therefore, patients may be suitable for discharge home with appropriate safety-net advice e.g. parents are to be encouraged to return if their child’s symptoms change or deteriorate (Ohle et al, 2011).

For scores equal or greater than 5, admission is recommended for further observation (65% sensitive in identifying the need for surgical intervention), whereas a score of equal or greater than 7 suggests the need for surgical intervention is highly likely (93% sensitivity)(Ohle et al, 2011).

The PAS has been adapted to specifically cater for the assessment of children (PEM (2002) and may be more useful in practice for those less experienced at examining children. Note the substitution of ‘coughing/hopping/percussion pain’ with greater emphasis (score=2) than ‘rebound pain’ (score=1) in the Alvarado score (Schneider et al, 2016). Furthermore, less importance is given to the presence of Leucocytosis, as in children there can be other more common causes such as UTI.

At the time of the first physical examination the child’s PAS was equal to 6;

Feature PASScore
Migration of pain 1
Anorexia 1
Nausea 1
Tenderness in the right lower quadrant 2
Elevated temperature 1
Leucocytosis 0
Shift of white cell count to the left 0
Coughing/hopping/percussion pain 0
Total = 6

The minimum PAS to suspect acute appendicitis is equal to or greater than 6 (Samuel, 2002), a score that recommends referral to surgical teams and blood sampling in order to ascertain the White Cell Count (WCC) and presence of Leucocytosis. Whilst not confirming acute appendicitis at this point, the clinical picture is clearly suggestive and promotes continued monitoring and admission to facilitate this.

A score equal to or, less than 5 recommends further observation is required, but does not attempt to predict which children will be best managed by admission. This remains a clinical judgement guided by the presentation of the child’s symptoms and examination, assessment of the parents and the experience of the clinician. Appropriate senior advice should always be sort for those clinicians lacking experience in examining children.

It should be noted that although this child did not initially present with pain induced by coughing/ hopping/or direct percussion, regular assessment by the surgical team whilst awaiting the blood results elicited pain on percussion later in the admission. The WCC result was raised >10 c/L and with increasing symptoms the child was taken to theatre later that same day for appendectomy.

Now what?

The Paediatric Appendicitis Score (PAS) attempts to stratify risk when diagnosing appendicitis in children presenting with abdominal pain (Samuel, 2002; Bhatt et al, 2009). Caution should be taken when using this tool to exclude appendicitis, in practice it should be utilised to support selection for surgical referral and as an indication for identifying the smaller population of children presenting with acute abdominal pain requiring invasive investigation such as blood tests.

Shiela Pantrini


Bhatt, M., Joseph, L., Ducharme, F.M., Dougherty, G. MSc, & McGillivray, D. (2009) Prospective Validation of the Pediatric Appendicitis Score in a Canadian Paediatric Emergency Department. Academic Emergency Medicine. 16:591–96

Driscoll, J. (2007) Practicing clinical supervision: a reflective approach for healthcare professionals (2nd edition). Elsevier. Edinburgh.

Ohle, R., O’Reilly, F., O’Brien, K.K., Fahey, T. & Dimitrov, B.D. (2011) The Alvarado score for predicting acute appendicitis: a systematic review. [on-line] BMC Medicine 9:139 (accessed 29/07/16)

Pediatric Emergency Medicine (PEM) Guidelines (2016) Appendicitis Clinical Practice Guidelines. (accessed 29/07/16)

Samuel, M. (2002) Pediatric Appendicitis Score. Journal of Pediatric Surgery 37(6):877-81

Schneider, C., Khabanda, A. & Bachur, R. (2016) Evaluating Appendicitis Scoring Systems Using a Prospective Pediatric Cohort. Annals of Emergency Medicine 49(6):778-84

One thought on “Paediatric appendicitis – Clinical decision rules

  1. John says:

    very useful yet most of the mesenteric adenitis I see would require admission on this system rather than what I do now outside of hospital which is review later but sooner if they get worse.

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