Appendicitis

Disclaimer These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.  Read the full CAHS clinical disclaimer

Aim 

To guide PCH Emergency Department (ED) staff with the assessment and management of right iliac appendicitis.

Background^1,2

• Appendicitis is one of the most common surgical conditions of the abdomen.
• Appendicitis, when it presents in the ‘classic’ way, is easy to diagnose clinically. However, appendicitis is notorious for having multiple manifestations with no single sign, symptom or investigation that is reliable to make the diagnosis.
• It is the most commonly misdiagnosed paediatric surgical condition.
• Appendicitis usually results from luminal obstruction of the appendix, followed by infection.

Risk

Delayed diagnosis of appendicitis may lead to perforation or sepsis.

Assessment

History

• The “classic” progression of symptoms is:
  • loss of appetite
  • dull periumbilical pain followed by nausea
  • migration of the pain to the right iliac fossa (RIF)
• Vomiting; after the onset of pain.
• Occasionally loose stools and fever.
• Occasionally irritative urinary symptoms, pyuria or haematuria due to an inflamed appendix adjacent to the bladder.
• Very young children with appendicitis may lack this history of progression and migration of pain and have a tendency towards early perforation and systemic illness.³ This finding also applies to those with communication difficulties such as in autism and global developmental delay.
• Menstrual and sexual history should be assessed in adolescent females.

Examination

A good approach to the diagnosis of appendicitis is to look for evidence of the following.

• Infection: This may include low-grade fever typically 24 to 48 hours after the onset of symptoms.
• Right iliac fossa (RIF) involvement: Pain, tenderness, localised peritonitis (guarding, rebound tenderness)
• The following signs are more relevant in older children
  • Rovsing sign (RIF pain when palpating the left iliac fossa)
  • Psoas sign (RIF pain on hyperextension of the right hip)
  • Obturator sign (RIF pain on internal rotation of the flexed right hip)
• The typical picture in the infant is the septic appearing child who has generalised abdominal tenderness
• If generalised peritonitis develops, then guarding and rebound tenderness also becomes generalised
• Non-abdominal features of the examination – such as ability to hop, move around, climb onto the trolley undistressed may help to support or refute the likelihood of appendicitis.

Investigations

Urine

• Always check urine to exclude urinary tract infections.
• Remember that appendicitis, as well as fever itself, may give rise to mild pyuria or haematuria.
• Urinary beta-human chorionic gonadotropin in adolescent females.

Blood tests

• Full blood count (FBC) / C-reactive protein (CRP): white cell count, absolute neutrophil count and CRP could be helpful in making a diagnosis of appendicitis¹. 

Paediatric Appendicitis Risk Calculator (pARC)⁴

• After initial assessment, urine testing and FBC, children age 5 years or above presenting with right iliac fossa pain can be risk stratified into likelihood of having acute appendicitis using the pARC score.
  • Refer to Pediatric Appendicitis Risk Calculator (pARC).
• Patients with a risk ≥ 75% should be admitted under the surgical team, made nil by mouth (NBM), commenced on IV Fluids and IV antibiotics after discussion with the surgical registrar. Further investigation including abdominal imaging should be requested and arranged by the surgical team if indicated.
• Patients with a risk 16-74% require abdominal ultrasound, requested and arranged by the Emergency Department team. Onwards management is determined based on findings.
• Patients with a risk ≤15% may be suitable for discharge with adequate pain control and safety net advice.

Additional Investigations

Additional investigations are usually not required unless they will change management.

• Urea, electrolytes and creatinine (UEC): Electrolyte abnormalities and dehydration need to be corrected before surgery but only require checking if child is dehydrated or been vomiting.
• Lipase / Liver Function Tests (LFT’s): Only require checking if underlying abdominal aetiology unclear.
• Ultrasound: First line imaging for suspected Appendicitis. Although this is not always required, decision to image should be guided using pARC score.
• Computerised Tomography (CT): Should only be ordered on the request of the surgeon or Senior ED Doctor, following their assessment of the patient.

Management

Initial management

Decisions relating to oral intake, fluids and antibiotics should be guided by the outcome of the pARC score. However, patients who are high risk (≥ 75%) of appendicitis should be managed according to the following principles.

• If shocked, resuscitate:
  • Insert IV cannula.
  • Bloods: FBC, UEC, CRP
  • IV fluid bolus sodium chloride 0.9% - 10 mL/kg and repeat if required.
• If not shocked, maintenance intravenous fluids alone.
• Electrolytes - correct significant abnormalities if indicated.
• The patient is to remain nil by mouth (NBM). Insert a nasogastric tube (NGT) if vomiting is continuous.
• Analgesia
• Antibiotics: IV antibiotics may be requested by the General Surgical Team once the diagnosis is confirmed.
  • Administer IV antibiotics early if patient is septic. Refer to - Sepsis recognition and management (ED Guideline).

If the diagnosis is uncertain

• In patients with persistent pain and where a clinical or ultrasound diagnosis of appendicitis could not be excluded, the child should have a review by the General Surgical Team.
• Patient to remain NBM until advised otherwise by the General Surgical Team.
• Some of these children will need to be admitted under a surgeon and observed for a period of 12-24 hours.
• During this observation period they may be kept NBM, given appropriate IV fluids, adequate analgesia and have regular abdominal examinations.

Low Risk of Appendicitis

• Patients have a low risk of appendicitis and may be discharged with safety net advice if:
  Low pARC score ≤15%
  • Low risk ultrasound findings - appendix <7 mm or not identified and no peri appendiceal inflammatory changes (fluid, fat stranding or hyperaemia).

Nursing

• Complete and record a full set of observations on the observation and response tool and record additional information on the Clinical Comments Chart.
• Minimum hourly observations.
• Minimum hourly pain score.
• Strict fluid balance chart.

Bibliography

1. Brandt M & Esperanza Lopez M. Acute appendicitis in children:Clinical manifestations and diagnosis (UpToDate) 2024
2. Gil, Lindsay A., Katherine J. Deans, and Peter C. Minneci. "Appendicitis in Children." Advances in Pediatrics. Academic Press Inc., 2023. 105-122.
3. Sakellaris G, Tilemis S, Charissis. Acute appendicitis in preschool-age children. Eur J Pediatr. 2005 Feb;164(2):80-3. Epub 2004 Nov 20.
4. Lee, W. H., O'Brien, S., McKinnon, E., Collin, M., Dalziel, S. R., Craig, S. S., & Borland, M. L. (2024). Study of pediatric appendicitis scores and management strategies: A prospective observational feasibility study. Academic Emergency Medicine, 31(11), 1089-1099.
5. Bravo, Michael, et al. "Identification of children with a nondiagnostic ultrasound at a low appendicitis risk using a pediatric appendicitis risk calculator." Academic Emergency Medicine 31.12 (2024): 1256-1263.
6. MDCalc ©2005-2024 (Cited 2025 November 11). Available from: https://www.mdcalc.com/calc/10201/pediatric-appendicitis-risk-calculator-parc#evidence

Endorsed by:	Nurse, Co-director, Surgical Services	Date:	Dec 2025
		Review date:	Dec 2028

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