Does a patient with calculous cholecystitis and ultrasound (US) signs of pancreatitis, but normal lipase levels, require a computed tomography (CT) scan?

From the Guidelines

A CT scan is necessary in this case of calculous cholecystitis with ultrasound findings suggesting pancreatitis, despite normal lipase levels, to accurately diagnose and manage potential complications. The presence of pancreatitis signs on ultrasound, even with normal lipase levels, warrants further investigation due to the possibility of early or mild pancreatitis where lipase might not be elevated 1. According to the 2024 clinical practice guideline update by the Infectious Diseases Society of America, if complications of acute cholecystitis or acute cholangitis are suspected, CT should be obtained as subsequent imaging 1.

Given the clinical scenario, the following points support the use of CT:

• Ultrasound limitations, such as abdominal tenderness and patient obesity, which may lead to equivocal results 1.
• The need for better visualization of the pancreas and surrounding structures to detect potential complications like pancreatic inflammation, necrosis, or fluid collections.
• The possibility of other causes of abdominal pain that might mimic or coexist with cholecystitis, which CT can help rule out.
• The importance of assessing the severity of both cholecystitis and pancreatitis to determine the appropriate management, including the need for urgent surgical intervention or drainage procedures.

Key considerations for the CT scan include:

• Preferably using CT with IV contrast for better visualization of the abdominal structures 1.
• The high clinical suspicion for acute cholecystitis and the presence of signs suggesting pancreatitis, which necessitate comprehensive imaging to guide treatment decisions.

From the Research

Diagnosis and Imaging

• Ultrasonography (US) is the preferred initial imaging technique for patients suspected of having acute calculous cholecystitis due to its high sensitivity in detecting gallbladder stones, real-time character, speed, and portability 2.
• US may show signs of pancreatitis, but normal lipase levels can make diagnosis challenging.
• Computed Tomography (CT) is particularly useful for evaluating complications of acute calculous cholecystitis 2, 3.

Role of CT in Diagnosis

• CT can help identify complications such as hemorrhagic, gangrenous, and emphysematous cholecystitis, as well as gallbladder perforation 3.
• Preoperative detection of complicated cholecystitis using CT can help care providers and operating surgeons prepare for a potentially more complicated procedure and course of recovery 3.

Management of Acute Calculous Cholecystitis

• Early laparoscopic cholecystectomy (ELC) is the recommended treatment for acute calculous cholecystitis, with high-risk patients potentially benefiting from alternative treatments like biliary drainage 4, 5.
• The use of broad-spectrum antibiotics is indicated for high-risk patients, especially in the presence of gallbladder necrosis 5.

Decision to Use CT

• Given the potential for complications and the importance of early diagnosis, CT may be considered as a secondary imaging modality to evaluate the extent of disease and guide management, even if US shows signs of pancreatitis with normal lipase levels 2, 3.