Ultrasound Case #3 – The Burger Pain

A 40 year old female presents to your ED with a chief complaint of RUQ pain that started 2 hours ago. She has no PMHx and notes that the pain only started right after she ate a hamburger. She denies ever having pain like this before.

Vitals on arrival” BP 126/80, Temp 37.4 C, HR 104, SpO2 100% on RA.

What do you see in these images and what is your next step in management?

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Clip 1 and 2 both show a long view of the gallbladder with a bright hyperechoic line close to the neck with posterior shadowing. These images do not show any obvious focal gallbladder wall thickening or pericholecystic fluid.
Clip 3 is labeled as “roll” indicating that we had the patient roll over onto their left sign. The reason that we did this is to confirm our suspicion that this was a stone in neck also known as SIN sign. If you see a stone in the gallbladder neck and you have the patient roll and the stone remains lodged in the neck you have confirmed a positive SIN sign. The SIN sign is highly specific for cholecystitis and should prompt a surgical consultation in the emergency department.

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In 2011 a paper published in Critical Ultrasound described the stone in neck (SIN) sign in 2011. (1) The authors found that SIN sing had a 97% specificity and a positive predictive value of 93% in diagnosing cholecystitis. For comparison, in general CT scan is 79.1% sensitive and 100% specific for cholecystitis. (2) In general ultrasound has shown 87% sensitivity and 82% specificity for diagnosing cholecystitis. (3) For each additional finding of cholecystitis you identify on your ultrasound you increase the specificity. SIN sign is the most specific.
The other 4 signs of cholecystitis are: GB wall thickening > 4mm, pericholecystic fluid, sonographic Murphy’s sign, and hydropic gallbladder measuring 10 x 5 cm or larger.

References
1. Nelson M, Ash A, Raio C, Zimmerman M. Stone-In-Neck phenomenon: A new sign of cholecystitis. Crit Ultrasound J. 2011;3(2):115–7.
2. Barakos JA, Ralls PW, Lapin SA, Johnson MB, Radin DR, Colletti PM, et al. Cholelithiasis: evaluation with CT. Radiology [Internet]. 1987 Feb;162(2):415–8. Available from: http://pubs.rsna.org/doi/10.1148/radiology.162.2.3797654
3. Scruggs W, Fox JC, Potts B, Zlidenny A, McDonough J, McDonough J, et al. Accuracy of ED Bedside Ultrasound for Identification of gallstones: retrospective analysis of 575 studies. West J Emerg Med [Internet]. 2008 Jan;9(1):1–5. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19561694