Final answer:
The diagnosis is likely Polymyalgia rheumatica, and the treatment is corticosteroids. PMR typically presents with pain and stiffness in specific areas of the body in patients over 50 and is associated with an elevated ESR. RA could present similarly, but usually targets different joints and involves additional diagnostic blood tests.
Step-by-step explanation:
A patient over 50 years old with pain and stiffness in the neck, shoulders, and pelvic girdle, and an elevated erythrocyte sedimentation rate (ESR) likely has a diagnosis of Polymyalgia rheumatica (PMR). The treatment for PMR is generally corticosteroids. PMR is characterized by quick onset of pain in the mentioned areas and is often associated with another condition called Giant cell arteritis, which would also be treated with corticosteroids but has additional symptoms such as headaches and visual problems. It's worth noting that Rheumatoid Arthritis (RA) could cause similar symptoms but usually affects the hands, feet, and cervical spine and is more common in people with declining estrogen levels, particularly post-menopausal individuals. The onset of RA typically ranges between 40 to 50 years. Diagnosing RA may include checking for rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP) through blood tests.