Treatment and diagnostic algorithm for pregnant women 2–3 trimesters with suspected acute appendicitis

Introduction. Diagnosing the causes of acute abdominal pain in pregnant women is challenging. Due to the absence of ionizing radiation and better visualization of the appendix compared to ultrasound, magnetic resonance imaging is increasingly recommended as an alternative for examining pregnant women with acute abdominal pain. However, in some cases, it is not possible to perform MRI, which limits the use of this method and necessitates stratification of pregnant patients according to the likelihood of adding MRI to the diagnostic complex.
The objective was to develop a model for predicting the risk of developing acute appendicitis in pregnant women in the 2nd and 3rd trimesters.
Methods and materials. The analysis of data of pregnant patients hospitalized at the Pavlov First Saint Petersburg State Medical University with suspected acute appendicitis was performed from January 2020 to January 2025 (n=94). The study took into account epidemiological, clinical, laboratory, instrumental, surgical and postoperative data. A univariate analysis was performed to predict the presence of acute appendicitis in pregnant women in the 2nd and 3rd trimesters, followed by the construction of a diagnostic model and the identification of risk classes. To confirm the quality of the constructed model, regression analysis was used followed by risk analysis.
Results. A model for predicting acute appendicitis in pregnant women in the 2nd–3rd trimesters was constructed based on clinical and laboratory parameters and ultrasound diagnostics with the identification of risk levels (AuRoc 0.84). The patients included in the average risk group underwent MRI to clarify the diagnosis of acute appendicitis and perform differential diagnostics with other pathologies of the abdominal cavity and pelvic organs. The proposed model for predicting acute appendicitis in pregnant women in the 2nd–3rd trimesters using MRI diagnostics in the average risk group has a high predictive quality (AuRoc 0.98) with a sensitivity of 96.9 % and a specificity of 97.6 %.
Conclusion. The identified factors (pain in the right lower quadrant of the abdomen, leukocyte level≥12.5·109/l, granulocyte percentage ≥76.4, positive Kocher sign, nausea/vomiting and C-reactive protein level> 6.0 mg/l) can be used to predict acute appendicitis in pregnant women in the 2nd and 3rd trimesters, taking into account the data of instrumental studies (ultrasound and MRI). The constructed model for predicting acute appendicitis, based on clinical and laboratory parameters and ultrasound diagnostics with the identification of risk levels, can be recommended for use in the diagnostics of acute appendicitis in pregnant women in the 2nd and 3rd trimesters. Stratification of pregnant women by the risk level of acute appendicitis allows for the reasonable use of MRI only in the average risk group for the purpose of differential diagnosis of the disease.

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