Objective: To determine if ultrasonography (US) and power Doppler (PD) may be useful in identifying polymyalgia rheumatica (PMR) patients with relapsing disease.
Methods: For a mean of 41 months, 57 consecutive untreated patients with PMR were prospectively assessed for relapses/recurrences. This cohort represented all the patients diagnosed over a 18-month period in one Italian secondary referral centre. Clinical signs and symptoms as well as ESR and CRP were evaluated. US examination of the shoulders was performed in all 57 patients at diagnosis and after the onset of prednisone treatment (mean 24 +/- 3 weeks). Power Doppler ultrasonography (PDUS) was performed in 24 patients. Shoulder sonograms were obtained according to standardized techniques.
Results: Prednisone therapy significantly reduced the frequency and the degree of subacromial/subdeltoid bursitis, long head biceps tenosynovitis and glenohumeral synovitis. At diagnosis, a positive PD signal was observed more frequently in the subacromial/subdeltoid bursae (33%). Prednisone therapy significantly reduced the frequency of patients with positive PD signal. Of the 44 patients in remission or with low disease activity at the time of the second US, 26 (59%) still had evidence of persistent inflammatory lesions. There was no association between the persistence of inflammation at US and relapses/recurrences; in contrast, a positive PD signal at diagnosis was significantly associated with the occurrence of relapses/recurrences at follow-up.
Conclusion: Subclinical inflammation detected by US persists in most PMR patients despite glucocorticoid treatment. PDUS may be useful to detect at diagnosis the patients with most active inflammation who have a higher risk of relapses/recurrences.