Dx: Is this gallstone a red herring?
The ultrasound image shows the gallbladder with a single mobile gallstone with posterior acoustic shadowing. The gallbladder wall is not thickened and there is no pericholecystic fluid (bottom image). The common bile duct does not appear dilated. The novice sonographer might at this point declare, “Aha, (I’m so smart) I found the cause of your pain”, but you realize that this case actually requires a bit deeper thought. The stone does not appear to be impacted in the gallbladder neck and so if it had been the cause of the patient’s pain, that pain should be gone or at least abating by now. However, her pain was actually continuing to worsen. A mobile gallstone may have caused an attack of biliary colic, but if the pain persists beyond 6 hours a diligent search for another cause needs to be considered. If a gallstone is lodged in the gallbladder neck it may be the nidus for early cholecystitis. If it is instead, mobile, it may just be a red herring. Since about 15% of adults have asymptomatic gallstones, the discovery of a gallstone in a patient with abdominal pain does not necessarily mean that it is or was the cause of the patient’s pain. Other common considerations should include acute appendicitis, kidney stones, pancreatitis, ulcers, enteritis, PID or a ruptured abdominal aortic aneurysm. Sending the patient home with a script for hydrocodone may do no more than mask a serious medical condition, adding insult to injury.
Astutely, you inform the patient that she has a gallstone, but you do not think that it is what is making her sick. Suspecting that what she actually may have is neither food poisoning, nor early cholecystitis, but rather colitis or even an atypically located appendicitis, you first repeat your physical exam and then decide to order a CT scan of the abdomen and pelvis. The CT demonstrates acute appendicitis with the tip of the appendix in an atypical location all the way in the right upper quadrant. This patient really forgot to read the medical books before coming in to see you. At least she didn’t have chronically elevated LFT’s from a fatty liver to add to the confusion. You pat yourself of the back for all the pitfalls you have avoided and then call one of your surgical colleagues, who books the OR and removes the appendix without complication.
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