Morphine-augmented cholescintigraphy and acute a calculous cholecystitis in critically ill patients: interest and new way of interpreting

Introduction: Acute acalculous cholecystitis (AAC) is a serious disease, difficult to diagnose in critically ill patients. The aim of the study was to evaluate the diagnostic performances of abdominal ultrasonography (US) and morphine-augmented cholescintigraphy (MC) and to improve diagnostic strategy in patients of intensive care unit (ICU) with suspected AA C. Methods: We retrospectively studied 82 consecutive ICU patients with suspected AA C. US was positive if the triad of gallbladder distension, gallbladder wall thickening and sludge was found. MC was positive if the gallbladder remained non-visualized after morphine injection. In a second time, other scintigraphic criteria of interpretation were tested, according to the visualization of the gallbladder before or after morphine administration. Treatment was decided on the basis of clinical, laboratory and imaging data. Results: The diagnosis of AAC was retained in 34 patients. US and MC had respectively for the diagnosis of AAC a sensitivity of 20.6 and 70.6%, and a specificity of 95.8 and 100%. Interpreting the MC as positive if the gallbladder remains non-visualized after morphine, as negative if it appears before, and as non-conclusive if visualized after, makes it possible to define respectively patients with high probability (100%), with low probability (7.5%) or with intermediate probability (39%) of AAC. Conclusions: MC is better than US for diagnosing AAC in critically ill patients, having in particular excellent specificity using the classical criteria of interpretation. MC must be thus performed in patients at risk for AAC, determined with clinical, laboratory and eventually echographic findings. To decrease false negative rate of MC, a probability categorical classification is proposed to improve patients' care. (author)