Shoulder ultrasonography in the diagnosis of polymyalgia rheumatica: A case-control study

Objective. Magnetic resonance imaging (MRI) showed that subacromial/subdelt oid bursitis is the most frequent shoulder lesion in polymyalgia rheumatica (PMR). We evaluated whether shoulder ultrasonography (US) was as effective as MRI in the detection of this lesion and assessed the sensitivity and sp ecificity of bilateral subacromial/subdeltoid bursitis in the diagnosis of PMR. Methods. A case-control study of 57 consecutive case patients with untreate d PMR and 114 controls seen over a 6 month period in 3 secondary referral r heumatology centers. Control patients consisted of the next 2 consecutive p atients with bilateral shoulder aching and stiffness observed after the cas e patient. In all case and control patients the glenohumeral joint space, b ursae, and lung head biceps tendon were assessed by bilateral shoulder US. The first 24 case patients were also examined by bilateral shoulder MRI. Results. US showed subacromial/subdeltoid bursitis in 55/57 (96%) patients with PMR and in 25/114 (22%) controls (p < 0.001). The lesion was bilateral in 53/55 (96%) case patients and in 1/25 (4%) controls (p < 0.001), Thr fr equency of glenohumeral joint synovitis and biceps tenosynovitis did not di ffer significantly between case patients and controls. In 100% of case pati ents MRI showed subacromial/subdeltoid bursitis confirming US findings. The sonographic evidence of bilateral bursitis had a sensitivity of 92.9%, spe cificity of 99.1%, and positive predictive value of 98.1% for the diagnosis of PMR. Conclusion. US and MRI were equally effective in confirming bilateral subac romial and subdeltoid bursitis in PMR. This finding, in view of its high se nsitivity and specificity, could be used as a new diagnostic criterion for PMR.