[Rhizomelic pseudopolyarthritis: update]

Crowned dens syndrome: a case report and review of the literature

The crowned dens syndrome (CDS), also known as periodontoid calcium pyrophosphate dehydrate crystal deposition disease, is typified clinically by severe cervical pain, neck stiffness and atlantoaxial synovial calcification which could be misdiagnosed as meningitis, epidural abscess, polymyalgia rheumatica, giant cell arthritis, rheumatoid arthritis, cervical spondylitis or metastatic spinal tumor. Crystalline deposition on cervical vertebrae is less well known disease entity and only a limited number of cases have been reported to date. Authors report a case of CDS and describe the clinical feature.

A rare case of crowned dens syndrome mimicking aseptic meningitis

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.

Case Presentation

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.

Conclusion

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.