From the Guidelines
The optimal investigation for this obese female with acute right upper quadrant (RUQ) pain and tenderness, who has a history of dyspepsia and biliary pain relieved by IV fluids and analgesics, would be ultrasound (US). Ultrasound should be the first-line imaging study in this case as it is readily available, non-invasive, cost-effective, and has high sensitivity for detecting gallstones and acute cholecystitis, which are the most likely diagnoses given the clinical presentation 1. Ultrasound can visualize gallstones, gallbladder wall thickening, pericholecystic fluid, and a sonographic Murphy's sign, all of which are indicators of acute cholecystitis. The absence of fever and jaundice suggests uncomplicated biliary disease, making ultrasound particularly appropriate.
Some of the key benefits of using ultrasound as the initial investigation include:
- High sensitivity for detecting gallstones and acute cholecystitis
- Readily available and non-invasive
- Cost-effective
- Can visualize gallstones, gallbladder wall thickening, pericholecystic fluid, and a sonographic Murphy's sign
If the ultrasound is inconclusive but clinical suspicion remains high, a HIDA scan would be the next appropriate test to evaluate gallbladder function and confirm cholecystitis 1. MRCP would be more appropriate if there was concern for choledocholithiasis with jaundice or abnormal liver enzymes, while ERCP is primarily therapeutic rather than diagnostic and carries risks of complications. It's also important to consider the limitations of ultrasound in obese patients, as noted in the 2024 clinical practice guideline update by the Infectious Diseases Society of America 1. However, the benefits of ultrasound outweigh these limitations, making it the optimal initial investigation for this patient.
From the Research
Optimal Investigation for Obese Female with Sudden RUQ Pain and Tenderness
The patient's symptoms of sudden right upper quadrant (RUQ) pain and tenderness, without jaundice or fever, suggest a possible gallbladder or biliary pathology. The optimal investigation for this patient would be:
- Ultrasound (US) as the initial evaluation, due to its high sensitivity and specificity in detecting gallbladder and biliary diseases 2, 3, 4
- US is a quick, reproducible, convenient, cheap, and low-risk technique, making it the most eligible technique in biliary pathology studies 2
- US can detect gallbladder abnormalities, such as cholelithiasis, cholecystitis, or suspicion of biliary tumors, and can also evaluate the bile ducts 2, 3
Alternative Investigations
Other investigations, such as:
- Magnetic Resonance Cholangiopancreatography (MRCP) may be reserved for problem-solving and evaluating patients with cholestatic presentation 3
- Computed Tomography (CT) may be used as part of a broader evaluation of patient's abdominal pain if non-gallbladder pathologies are also suspected 3, 5
- Hepatobiliary Iminodiacetic Acid (HIDA) scan may be used to evaluate gallbladder function, but it is not the initial investigation of choice for this patient's symptoms
Rationale
The choice of US as the initial investigation is based on its high diagnostic accuracy, convenience, and low risk, making it an ideal modality for evaluating gallbladder and biliary diseases 2, 3, 4. The other investigations, such as MRCP, CT, and HIDA scan, may be used as adjuncts or alternatives, depending on the patient's specific clinical situation and the results of the initial US evaluation 3, 5.