Investigations

1st investigations to order

Test
Result
Test

Increased polymorphonuclear leukocytes (>75%). High discriminatory power when combined with history.[52]

Leukocytosis ≥16,000/microliter and CRP level on admission ≥10 mg/L are strong predictive factors for appendicitis in children.[10]

Result

mild leukocytosis (10,000 to 18,000/microliter)

Test
Result
Test

C-reactive protein is likely to be elevated.[38]

CRP level on admission ≥10 mg/L and leukocytosis ≥16,000/microliter are strong predictive factors for appendicitis in children

Result

there is no clear cut-off value for a raised CRP in children, CRP likely to be elevated

Test
Result
Test

Wall thickening, wall enhancement, and inflammatory changes in the surrounding tissues are additional findings seen in a CT scan of abdomen and pelvis.[53]com.bmj.content.model.Caption@6440fc41[Figure caption and citation for the preceding image starts]: CT abdomen - thickened appendix.Nasim Ahmed, MBBS, FACS; used with permission [Citation ends].

Appendiceal CT scan is increasingly used as the initial diagnostic test for acute appendicitis, and it is routine practice in the US to request a CT for patients presenting to the emergency room with features of acute appendicitis.[26] A CT is also indicated in atypical presentations.[30][48]

Intravenous contrast-enhanced CT scan with or without oral contrast has up to 100% sensitivity compared with 92% sensitivity in nonintravenous, contrast-enhanced CT scan.[50][51]

In pregnant women presenting with features of appendicitis, an abdominal sonogram should be performed to identify the appendix. If the sonogram examination is inconclusive, abdominal MRI (particularly in early pregnancy) may be appropriate.[30][48]

Result

abnormal appendix (diameter >6 mm) identified or calcified appendicolith seen in association with periappendiceal inflammation, fat stranding

Test
Result
Test

If positive, the possibility of ectopic pregnancy should be considered.

Result

negative

Investigations to consider

Test
Result
Test

In children, point-of-care ultrasound is the most appropriate first-line diagnostic tool, if an imaging investigation is indicated based on clinical assessment.

Sensitivity and specificity of ultrasound may be higher in children compared with adults.[43][45][46]

In children with inconclusive ultrasound results, a second-line imaging technique (CT or MRI) can be chosen based on local availability and expertize.[10]

Result

aperistaltic or noncompressible structure with outer diameter >6 mm, fluid collection if perforated, fat stranding, appendicolith

Test
Result
Test

If positive for red cells, white cells, or nitrates, an alternative diagnosis such as renal colic or urinary tract infection should be considered.

Result

negative

Test
Result
Test

In pregnant women presenting with features of appendicitis, an abdominal sonogram should be performed to identify the appendix. If the sonogram examination is inconclusive, abdominal MRI (particularly in early pregnancy) may be appropriate.[30][48]

A negative or inconclusive MRI does not exclude appendicitis and surgery should still be considered if clinical suspicion is high.[10]

Result

abnormal appendix (diameter >6 mm) identified and evidence of periappendicial inflammatory changes, appendicolith, fat stranding

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