Interspinous bursitis is common in polymyalgia rheumatica, but is not associated with spinal pain

Dario Camellino, Francesco Paparo, Silvia Morbelli, Maurizio Cutolo, Gianmario Sambuceti, Marco A Cimmino

IntroductionPolymyalgia rheumatica (PMR) is a common inflammatory disease of the elderly characterized by shoulder/pelvic girdle, and cervical and, occasionally, lumbar pain. Interspinous bursitis has been suggested as a potential cause of spinal symptoms. We evaluated, by 18 F-Fluorodeoxyglucose (FDG) positron emission tomography integrated with computed tomography (PET/CT), the vertebral structures involved in PMR in a cohort of consecutive, untreated patients.MethodsSixty-five consecutive patients with PMR were studied. After a standardized physical exam, which included evaluation of pain and tenderness in the vertebral column, they underwent FDG-PET/CT. Sites of increased uptake and their correlation with spontaneous and provoked pain were recorded. For comparison, FDG-PET/CT was performed also in 65 age- and sex-matched controls and in 10 rheumatoid arthritis (RA) patients.ResultsThe most frequent site of spontaneous and provoked pain was the cervical portion. FDG uptake was more frequent in the lumbar portion than at any other locations, and in the cervical than in the thoracic portion (P <0.0001). No correlation was found between uptake and spontaneous or provoked pain. There was an association between presence of cervical and lumbar bursitis (r =0.34, P =0.007). None of the control patients and one out of ten RA patients showed interspinous bursitis.ConclusionsInterspinous bursitis is a frequent finding in the lumbar spine of patients with PMR. However, it is not associated with clinical symptoms and can hardly explain the spinal pain reported by the patients. Cervical pain is more frequent than lumbar pain in PMR patients and may be caused by shoulder girdle involvement.