Crowned dens syndrome: a neurologist's perspective.

Crowned dens syndrome is an under-recognized entity that can mimic neurological disease, in particular meningitis or giant-cell arteritis. We present a 48-year-old woman presenting with an inflammatory meningitis-like syndrome with headache and neck stiffness. Lumbar puncture was normal and computed tomography (CT) of the atlantoaxial joint showed abnormal calcifications around the odontoid process, leading to a tentative diagnosis of crowned dens syndrome. In addition, signs of active inflammation in and around the dens were present on cervical MR imaging. Since CDS can mimic meningitis or giant-cell arteritis, neurologists should be aware of this entity. If CDS is suspected, the bone window on the head CT scan can lead to the diagnosis. On the other hand, asymptomatic periodontoid calcifications are common and should not preclude further investigations.