Postprandial Referred Shoulder Pain: A Case Report

The precise mechanism of referred pain is not well understood; however, diaphragmatic irritation is a well-known etiology of referred pain. Left side referred pain due to diaphragmatic irritation is most commonly attributed to splenic laceration i.e. Kerr's sign. Here, we report an unusual case of left-sided referred pain that followed eating. An adult male presented vague and chronic left shoulder pain that followed eating. The pain was described as a deep boring type of discomfort that was poorly localized to the region deep to the acromion and extended superomedially along the upper fibers of the trapezius muscle. The pain was present immediately after eating heavy meals and always abated approximately 30 minutes later. There was no history of previous surgery and physical examination was unremarkable. CT examination of the abdomen and thorax did not show any pathology or anatomical variations that would result in such referred pain. Although the exact etiology of this case is unclear, the most likely cause would be left-sided diaphragmatic irritation from the stomach after eating. The current literature does not enclose reports pertaining to similar findings. Although unusual and seemingly rare, postprandial referred shoulder pain should be considered by clinicians alongside other causes of referred shoulder pain when presented with shoulder pain without an obvious musculoskeletal or neural etiology.