The calculator in question is the Classification Criteria for Polymyalgia Rheumatica (PMR). This scoring system is used in the clinical setting to help diagnose patients suspected of having polymyalgia rheumatica, a condition characterized by muscle pain and stiffness, particularly in the shoulder and hip regions.
The criteria are applicable to patients aged 50 years and above who have bilateral shoulder pain and stiffness for at least one month, and who have elevated inflammatory markers such as C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR).
The clinical utility of this calculator is to aid in the diagnosis of PMR, which can be challenging due to its nonspecific symptoms and the absence of a definitive diagnostic test. The criteria can also help differentiate PMR from other conditions with similar symptoms, such as rheumatoid arthritis or giant cell arteritis.
Exclusion criteria for the use of this calculator include the presence of other diseases that could explain the patient's symptoms, such as active infections, malignancies, or other rheumatic diseases. Additionally, patients with recent use of corticosteroids, which can mask the symptoms of PMR, may not be suitable for this scoring system.
Reference
Bhaskar Dasgupta, Marco A Cimmino, Hilal Maradit-Kremers et al. 2012 provisional classification criteria for polymyalgia rheumatica: a European League Against Rheumatism / American College of Rheumatology collaborative initiative. Ann Rheum Dis. 2012 Apr;71(4):484-92.
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