Crowned dens syndrome, yet another rheumatic disease imposter.

Crowned dens syndrome (CDS) is defined as acute cervical or occipital pain due to a local inflammatory reaction related to calcifications in the ligaments surrounding the odontoid process. Virtually, all previous descriptions of CDS have related to calcium pyrophosphate dehydrate (CPPD) arthropathy. We prospectively identified a total of twenty-four consecutive inpatients with Crowned dens syndrome from January 2016 to December 2017 in our institution. All patients (age range 54 to 87 years, 67% females) presented with acute onset pain in the upper neck and/or occiput accompanied with extreme neck stiffness. Most patients (79%) had elevated inflammatory markers. Four patients underwent temporal artery biopsy, which was negative for arteritis in all cases, and one was subjected to lumbar puncture, which was non-contributory. Seventeen patients (71%) had known rheumatic disease on presentation: 10 patients had the diagnosis of calcium pyrophosphate dehydrate arthropathy, 3 patients had ankylosing spondylitis, 2 patients had rheumatoid arthritis, 1 patient had Behcet's disease, and 1 suffered from Familial Mediterranean Fever. In 4 more patients, crowned dens syndrome was the presenting symptom of calcium pyrophosphate dehydrate disease. All patients were treated with glucocorticoids as 0.5 mg/kg prednisone plus colchicine 0.5 mg bid resulting in dramatic improvement in both clinical (head/neck pain alleviated and cervical spinal mobility regained) and laboratory measures. Crowned dens syndrome should be considered, and craniocervical junction imaged in the context of acute cervical or occipital pain with stiffness and elevated inflammation markers not only in patients previously diagnosed with calcium pyrophosphate dehydrate arthropathy but also in diverse clinical settings.Key Points• This report highlights that crowned dens syndrome should be considered in various clinical setting besides calcium pyrophosphate dehydrate (CPPD) arthropathy.• Vigilance to this syndrome allows rapid treatment and may spare the patient unnecessary invasive procedures (i.e., temporal artery biopsy or lumbar puncture).