[Low back pain and MRI-abnormalities: atypical polymyalgia rheumatica].

A 64-year-old man was admitted to hospital with increasing low back pain, radiating to his upper legs. MRI of the lumbar spine showed inflammatory lesions of vertebrae L3-L5, after which the patient was treated with flucloxacilline for 6 weeks. However, he did not improve and the pain became more extensive. Finally, PET-CT study showed abnormalities in shoulders, back and hips, indicating a probable diagnosis of polymyalgia rheumatica. Upon treatment with prednisone, the pain quickly decreased and 3 months later the inflammatory changes visible on MRI were clearly reduced. Polymyalgia rheumatica (PMR) is often recognized by its typical clinical presentation, but in atypical cases, investigation using imaging may be helpful. Abnormalities in shoulder and hip joints are most common, but signs of cervical and lumbar interspinous bursitis might also be found in patients with PMR.