Crowned dens syndrome misdiagnosed as polymyalgia rheumatica, giant cell arteritis, meningitis or spondylitis: an analysis of eight cases

Background. The crowned dens syndrome, related to microcrystalline deposition in the peri-odontoid articular and abarticular structures, is mainly responsible for acute or chronic cervical pain. Patients. We report eight cases of crowned dens syndrome with atypical presentations mimicking giant cell arteritis, polymyalgia rheumatica, meningitis or discitis. The clinical and radiological aspects of these cases are presented and discussed. Results. For all patients, fever, cervical stiffness, headaches and biological inflammatory syndrome were reported. For three patients, impairment of general condition, occipito-temporal or mandible pain and weakness with inflammatory pain of the shoulder girdle was suggestive of giant cell arteritis and/or polymyalgia rheumatica, leading to temporal artery biopsy and/or long-term steroid treatment. Recurrence of clinical symptoms when tapering steroids was noted. In two cases, previous breast carcinoma led to the initial diagnosis of metastatic spondylitis. For three patients with vomiting, nausea and Kernig's and/or Brudzinski's sign, the first diagnosis was meningitis, leading to unhelpful lumbar puncture. In all cases, diagnosis of crowned dens syndrome once evoked, was confirmed by cervical CT scanning and dramatic improvement with non-steroidal anti-inflammatory drugs or colchicine. Conclusion. This under-recognized entity must be considered as a differential diagnosis of meningitis and discitis, but also of giant cell arteritis and polymyalgia rheumatica, as well as a possible aetiology for fevers of unknown origin. CT scanning is necessary for diagnosis. Clinicians should be aware of such misleading clinical presentations.