MSFinals-2511
Liam is a 50-year-old man who visits his GP complaining of fatigue and low mood. Upon further inquiry, he reveals experiencing muscle stiffness, particularly in his shoulders, which can last up to an hour upon waking. During examination, there is no apparent joint swelling, and power is 5/5 in all muscle groups. However, movement is painful during shoulder abduction and elevation. Despite the pain, there is good range of movement, and there are no other neurological symptoms. Liam has a medical history of type 2 diabetes, for which he takes metformin. What is the most probable diagnosis?