[Acute neck pain caused by calcium pyrophosphate dehydrate deposition in the transverse ligament of the atlas: a case report].

We report a case of pseudogout manifested by severe posterior neck pain. Pseudogout of the neck, also known as the crowned dens syndrome, causes acute neck pain characterized by calcium pyrophosphate dehydrate deposition around the odontoid process. Crowned dens syndrome is typified clinically by severe cervical pain and stiffness, often in conjunction with raised inflammatory markers. A 71-year-old man presented with severe neck pain. On admission, elevation of serum CRP level was confirmed. Magnetic resonance images showed no responsible abnormalities except for degenerating change of the spine. The patient was diagnosed as having pseudogout caused by calcium pyrophosphate dehydrate deposition based on cervical computed tomographic imaging, which showed linear calcification in the transverse ligament of the axis. After administration of non-steroidal anti-inflammatory drugs, the fever and neck pain disappeared and the CRP level returned to within the normal range. Pseudogout of the cervical spine should be considered as a differential diagnosis when we examine patients with acute neck pain. Cervical spinal computed tomographic scan is a more sensitive and useful examination method to diagnose this disease rather than magnetic resonance images.