The Crystal Crown
A74-year-old man with a history of acute myeloid leukemia presented with right shoulder and neck pain and fever of 2-day’s duration. Physical examination revealed a temperature of 39 C (102.2 0 F), right shoulder joint tenderness, and negative Kernig and Brudzinski signs. Workup revealed leukopenia with an absolute neutrophil count of 0.29 x 109 /L (1.56 to 6.45 x 109 /L). Head and cervical vertebrae computed tomography (CT) scan results were reported to be negative. He was started on vancomycin and cefepime for neutropenic fever. Later, this was de-escalated to prophylactic antimicrobials, as the results of the infectious workup were negative. Subsequently, the patient developed acute bilateral foot pain and worsening shoulder pain. Erythrocyte sedimentation was 130 mm/h (0 to 22 mm/1 h), C-reactive protein was 23.1 mg/L (<=8.0 mg/L), and uric acid was 3.4 mg/dL (3.7 to 8.0 mg/dL). Right-shoulder arthrocentesis showed rhomboid-shaped and positive birefringent crystals consistent with calcium pyrophosphate deposition disease (CPPD).

A dual energy CT (DECT) scan showed bilateral ankle-joint and midfoot diffuse calcium deposition consistent with CPPD. Given these findings, our suspicion for crowned dens syndrome (CDS) was high. We reviewed the cervical spine CT scan obtained on admission, and calcifications of the transverse ligament were detected, which confirmed the diagnosis of CDS. The patient was started on 40 mg prednisone with a slow taper over 2 weeks, after which there was complete resolution of his symptoms.

CDS is a rare syndrome characterized by severe neck pain, fever, and elevated inflammatory markers. CT scan is the gold standard for diagnosis. The key radiographic finding is the presence of periodontoid calcification in a crown or halo configuration. CDS responds favorably to treatment with oral nonsteroidal anti-inflammatory drugs, colchicine, and corticosteroids.2 As CDS presents with febrile neck pain, it can mimic other disorders such as meningitis, giant cell arteritis, and polymyalgia rheumatica. A high index of suspicion is required to diagnose CDS, as it can be frequently missed on imaging.