Objective: To study the usefulness of ultrasonography (US) in predicting the diagnostic outcome in patients with polymyalgic symptoms.
Methods: Sixty-one elderly patients with polymyalgic syndrome were recruited in a secondary care setting and followed up in a prospective way. Clinical, laboratory, and US data obtained at onset were re-evaluated after 1 year when diagnostic outcome was defined.
Results: A diagnostic shift was observed in 32 polymyalgic patients (52%). Calcium pyrophosphate deposition disease (CPDD) was diagnosed in nine patients, elderly-onset rheumatoid arthritis (EORA) in 18, and elderly-onset spondyloarthritis (EOSpA) in five. In polymyalgia rheumatica (PMR) patients US demonstrated synovitis in 90% of cases, in both proximal (90%) and peripheral joints (41%). The best predictive US model for the definitive diagnosis of PMR comprised: the presence of subacromial-subdeltoid bursitis [odds ratio (OR) 5.603, p = 0.003], low frequency of wrist (OR 0.074, p < 0.001), metacarpophalangeal (OR 0.052, p < 0.001), and metatarsophalangeal effusion/synovitis (OR 0.107, p < 0.027), low frequency of knee menisci chondrocalcinosis (OR 0.091, p = 0.013), tendinous calcaneal calcifications (OR 0.078, p = 0.006), and Achilles enthesitis (OR 0.107, p = 0.027), and low power Doppler US (PDUS) scores at wrist (OR 0.052, p < 0.001).
Conclusions: US and PDUS can be useful in distinguishing, at onset of disease, pure PMR from other diseases mimicking this condition.