title: A rare case of crowned dens syndrome mimicking aseptic meningitis.
abstract: BACKGROUND
  Crowned dens syndrome (CDS), related to microcrystalline deposition in the periodontoid process, is the main cause of acute or chronic cervical pain. Microcrystal-line deposition most often consists of calcium pyrophosphate dehydrate crystals and/or hydroxyapatite crystals.
  
  
  METHODS
  This report describes the case of an 89-year-old woman who presented with sudden onset, high fever, severe occipital headache, and neck stiffness. A laboratory examination revealed a markedly elevated white blood cell count (11,100/µl) and C-reactive protein level (23.8 mg/dl). These clinical findings suggested severe infection such as meningitis with sepsis. However, the results of blood culture, serum endotoxin, and procalcitonin were all negative, and cerebrospinal fluid studies revealed only a slight abnormality. The patient was first diagnosed with meningitis and treated with antiviral and antibiotic agents as well as non-steroidal anti-inflammatory drugs, but they only had limited effects. A cervical plain computed tomography (CT) scan and its three-dimensional (3D) reconstruction detected a remarkable crown-like calcification surrounding the odontoid process. On the basis of the CT findings, the patient was diagnosed as a severe case of CDS and was immediately treated with corticosteroids. The patient's condition drastically improved within a week after one course of corticosteroid therapy.
  
  
  CONCLUSIONS
  Some atypical symptoms of CDS are misleading and may be misdiagnosed as meningitis, as happened in our case. A CT scan, especially a 3D-CT scan, is necessary and useful for a definitive diagnosis of CDS. CDS should be considered as a differential diagnosis of a possible etiology for fever, headache, and cervical pain of unknown origin.
authors.affiliation: Department of Neurology, Hino Municipal Hospital, Keio University, Tokyo, Japan.
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Takahashi
authors.forename: Yugo
authors.initials: Y
authors.lastname: Minakata
authors.forename: Masato
authors.initials: M
authors.lastname: Tamura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Takasu
authors.forename: Marohito
authors.initials: M
authors.lastname: Murakami
keywords: Calcium pyrophosphate dehydrate crystals; Cervical computed tomography scan; Corticosteroids; Crowned dens syndrome; Meningitis; Odontoid process