MRCP2-4599
A 68-year-old woman presents to her GP with a 2-week history of progressive shoulder pain. She reports difficulty getting dressed in the morning due to the pain. She also feels weak and fatigued and has lost around 2 kg in weight. There is no significant medical history. On examination, she has a temperature of 37.8 °C, heart rate of 90 bpm, and blood pressure of 127/77 mmHg. Heart sounds are normal, and breath sounds are vesicular bilaterally. Abdomen is soft and non-tender with no palpable organomegaly. Bilateral proximal muscle stiffness is noted. What is the most likely diagnosis?