Which condition causes pain and stiffness in muscles and joints, commonly seen in elderly patients?

Polymyalgia rheumatica is a condition that commonly affects older adults, typically those over 50, and is characterized by pain and stiffness in the muscles and joints, particularly in the shoulders, neck, and hips. The onset is often abrupt and can lead to significant discomfort and limitations in daily activities.

The underlying cause of polymyalgia rheumatica is thought to be related to an inflammatory process in the body, although the exact etiology remains unclear. This condition is distinct from osteoarthritis and rheumatoid arthritis, which have different pathophysiological mechanisms and clinical presentations. Unlike fibromyalgia, which primarily involves widespread pain and may also include non-restorative sleep and fatigue, polymyalgia rheumatica's stiffness is notably worse in the morning and improves with movement throughout the day.

In summary, the choice of polymyalgia rheumatica aligns with its characteristic presentation in the elderly, making it the most fitting answer for the given question.