Appendicitis Clinical Pathway — Emergency Department

Imaging

Imaging Choices

US is the study of choice for assessing suspected appendicitis.
US, CT, and MRI are equivalent for identifying a normal appendix in children
CT and MR are equivalent for identifying appendicitis after a first-line ultrasound.

Common reasons for non-visualized appendix on US are:

Abundant stool and gas in the RLQ
Variant positioning of the appendix
- Deep pelvis or retrocecal, followed by mid-pelvis or subhepatic
Patient guarding due to pain
Limitations on US due to body habitus, e.g. obesity, severe scoliosis, etc

Initial study to assess for appendicitis in pts < 100 kg

Male:
Female:

US Abd RLQ – Appendicitis only
US Abd RLQ – Appendicitis only
Consider US Pelvis w/ doppler, but do not delay US Abd RLQ

MRI

Initial study of choice for pts > 100 kg as US visualization is limited
Non-contrast (no IV, no PO)
30 minute scan time
Patients are typically not sedated
May identify other causes of abdominal inflammation
Note: Normal ovaries on MRI rules out ovarian torsion
Abnormal ovary on MRI may require US Pelvis w/ doppler

CT Abdomen/Pelvis

Contrast enhanced, IV only, no PO
Scan time < 1 minute
Appropriate for children who are unable to tolerate 30 min scan time
- e.g., Too young, agitated, or neurodevelopmental concerns

Interpreting the US Results

Appendix not seen and No secondary signs	Consider as low probability for appendicitis Consider other causes of RLQ pain GE, mesenteric lymphadenitis, constipation, UTI, etc. For further imaging evaluation Abdominal XR or other US image may be useful directed by clinical evaluation and differential If appendicitis is still high in the differential, cross-sectional imaging (CT or MRI) will be needed.
Appendix not seen and Positive secondary signs	Consider as high probability for appendicitis or another inflammatory process Differential may include the following among other possibilities: Perforated or non-perforated appendicitis Inflammatory bowel disease Meckel complication Pelvic inflammatory disease Tubo-ovarian abscess Osteomyelitis Pyelonephritis Neoplasm Consider Surgical Consultation Cross-sectional imaging (CT or MRI) will be needed to better characterize source of inflammation.

Appendix not seen
and
No secondary signs

Consider as low probability for appendicitis
Consider other causes of RLQ pain
- GE, mesenteric lymphadenitis, constipation, UTI, etc.
For further imaging evaluation
- Abdominal XR or other US image may be useful directed by clinical evaluation and differential
If appendicitis is still high in the differential, cross-sectional imaging (CT or MRI) will be needed.

Appendix not seen
and
Positive secondary signs

Consider as high probability for appendicitis or another inflammatory process
Differential may include the following among other possibilities:
- Perforated or non-perforated appendicitis
- Inflammatory bowel disease
- Meckel complication
- Pelvic inflammatory disease
- Tubo-ovarian abscess
- Osteomyelitis
- Pyelonephritis
- Neoplasm
Consider Surgical Consultation
Cross-sectional imaging (CT or MRI) will be needed to better characterize source of inflammation.

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The clinical pathways are based upon publicly available medical evidence and/or a consensus of medical practitioners at The Children’s Hospital of Philadelphia (“CHOP”) and are current at the time of publication. These clinical pathways are intended to be a guide for practitioners and may need to be adapted for each specific patient based on the practitioner’s professional judgment, consideration of any unique circumstances, the needs of each patient and their family, and/or the availability of various resources at the health care institution where the patient is located.

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