Ultrasound scanning in the diagnosis of acute appendicitis in pregnancy

Date First Published:
March 1, 2000
Last Updated:
March 20, 2007
Report by:
Robert Williams, Specialist Registrar in Emergency Medicine (Royal Oldham Hospital)
Search checked by:
Jonathan Shaw, Royal Oldham Hospital
Three-Part Question:
In [women with possible appendicitis in pregnancy] is [abdominal ultrasonography] good at [ruling in or ruling out appendicular disease]
Clinical Scenario:
A 28 year old woman presents to the emergency department with a 4 hour history of right iliac fossa pain, and an examination suggestive of acute appendicitis. You are aware that an isolated blood count is neither specific nor sensitive in the diagnosis of appendicitis, and the on-call surgeon suggests that an ultrasound scan may be helpful.
Search Strategy:
Medline 1950 to February Week 2 2007
Embase 1980 to 2007 Week 08. Using the OVID interface
The Cochrane Library Issue 1 2007
Search Details:
[appendicitis.mp. or exp Appendicitis/] OR [exp Ultrasonography/ or ultrasonography.mp. OR ultrasound.mp. OR sonography.mp.] AND [exp Pregnancy/ OR exp Pregnancy Complications/ OR exp Pregnancy, Abdominal/ OR pregnancy.mp.] Limit to English language and Human.
Diagnosis Clinical Query filter (specificity)

Cochrane:Appendicitis[MeSH explode all trees] AND Pregnancy [MeSH explode all trees] 0 results
Outcome:
10 papers were found, of which 7 were irrelevant or of insufficient quality for inclusion. The 3 remaining papers are shown below
Relevant Paper(s):
Study Title Patient Group Study type (level of evidence) Outcomes Key results Study Weaknesses
Diagnosis of acute appendicitis in pregnant women: value of sonography. Lim HK, Bae SH, Seo GS. 1992, Korea 42 pregnant women with clinically suspected appendicitis.
Gold standard operative finding (22) or observation for a median of 3 weeks (23)		 Diagnostic test study Sensitivity of USS 100% Small numbers
Unclear selection
Varying trimesters
3 women in third trimester excluded as uterus too large
Specificity of USS 96%
Likelihood ratios Positive 27.0<br><br>Negative 0.060
Sonography of acute appendicitis in pregnancy. Barloon TJ, Brown BP, Abu-Yousef MM et al. 1995, USA 22 pregnant women with clinically suspected acute appendicitis.
Gold standard operative finding or clinical follow up for a mean period of 19 months (6 to 36 months)		 Diagnostic test study Sensitivity of USS 67% Those not presenting with 'classical acute appendicitis' were not scanned
Small numbers
Varying trimesters scanned
Specificity of USS 95%
Likelihood ratios Positive 12.6%<br><br>Negative 0.35
Diagnostic imaging of suspected appendicitis in pregnant women: Comparison of CT to ultrasonography. Mullins ME. Rhea JT. Greene MF. Novelline RA. 2001, USA 29 women with suspected appendicitis who had ultrasound scans performed over a 12 year period
Gold standard operative findings or record review		 Retrospective cohort Sensitivity of USS 100% 22 indeterminate scans not included in analysis thus reported clinical utility is for 7 scans
Specificity of USS 83.30%
Author Commentary:
The results of these studies need to be viewed with caution. All suffer from the handicap of small numbers, likely selection biases and the absence of a gold standard. The analysis of the third study is seriously flawed in that indeterminate scans are not included.
Bottom Line:
A positive USS may be useful in the diagnosis of acute appendicitis during pregnancy. Those patients with a negative scan should be further investigated and observed until the symptoms resolve or an alternative diagnosis is reached.
References:
  1. Lim HK, Bae SH, Seo GS.. Diagnosis of acute appendicitis in pregnant women: value of sonography.
  2. Barloon TJ, Brown BP, Abu-Yousef MM et al.. Sonography of acute appendicitis in pregnancy.
  3. Mullins ME. Rhea JT. Greene MF. Novelline RA.. Diagnostic imaging of suspected appendicitis in pregnant women: Comparison of CT to ultrasonography.