Investigations

1st investigations to order

CBC

Test
Result
Test

Increased polymorphonuclear leukocytes (>75%). High discriminatory power when combined with history. [39]

Result

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

abdominal and pelvic CT scan

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. [40] com.bmj.content.model.Caption@59287c92 [Figure caption and citation for the preceding image starts]: CT abdomen - thickened appendix. Nasim Ahmed, MBBS, FACS; used with permission [Citation ends].

It has become common practice, especially in the US, for any patient presenting to the emergency department with abdominal pain suggestive of appendicitis, to have CT scan of the abdomen and pelvis, unless the patient is pregnant. A CT is also indicated in atypical presentations.

The sensitivity and specificity of CT scan in detecting acute appendicitis have been reported to be 94% and 95%, respectively. [33]

In pregnant women presenting with features of appendicitis, an abdominal sonogram should be performed to identify the appendix. If the sonogram examination is inconclusive, either an abdominal MRI (particularly in early pregnancy) or a CT scan should be performed. [21]

Result

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

urinary pregnancy test

Test
Result
Test

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

Result

negative

Investigations to consider

abdominal ultrasound

Test
Result
Test

Operator-dependent.

Indicated in atypical presentations. May be preferred in children in order to limit radiation exposure with CT scan. [32]

The sensitivity and specificity of ultrasound in detecting acute appendicitis have been reported to be 86% and 81%, respectively. [33]

Result

aperistaltic or noncompressible structure with outer diameter >6 mm

urinalysis

Test
Result
Test

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

Result

negative

abdominal and pelvic MRI in pregnancy

Test
Result
Test

MRI can be used as an alternative to CT scan in pregnancy, particularly in early pregnancy. Its results are comparable to CT scan in pregnant patients for whom sonographic findings are equivocal for the diagnosis of acute appendicitis. [41] [21]

Result

abnormal appendix (diameter >6 mm) identified and evidence of periappendicial inflammatory changes

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