911 - Coronated By Calcium: Manifestations of Crowned Dens Syndrome, A Case Report

An 85-year-old male presented to the emergency department with several weeks of neck pain and bilateral upper extremity numbness. MRI of the cervical spine demonstrated myelopathy with mild to moderate cervical spinal stenosis and moderate to severe foraminal stenosis from C2-C7. The patient underwent C5-6 anterior cervical discectomy & fusion followed by acute rehabilitation. While undergoing rehab the patient began to decline, ultimately requiring maximum assistance in therapy.  He endorsed worsening neck pain and quadriparesis exacerbated during therapy. He was found to have elevated C-reactive protein (CRP)  and erythrocyte sedimentation rate (ESR) prompting a repeat CT revealing an inflammatory process at C1-C2, suggestive of crowned dens syndrome (CDS). Anakinra was initiated and he subsequently endorsed symptom improvement. Follow up lab work weeks later showed inflammatory markers within normal limits.

Discussions:

CDS is an uncommon manifestation of calcium pyrophosphate dihydrate (CPPD) deposition, reported in approximately 7% of CPPD cases. It is characterized by crystal accumulation in the atlantoaxial joint, particularly around the dens. Patients typically present with acute neck pain and stiffness, often accompanied by fever and elevated ESR and CRP. In some cases, crystal deposition in the cervical ligamentum flavum or posterior longitudinal ligament may lead to spinal stenosis, spinal cord compression, or acute nerve compression syndromes. 

The exact pathophysiology of CPPD crystal deposition remains unclear, though contributing factors include age, genetic predisposition, trauma (including surgery), and metabolic disorders. Importantly, CDS is rarely an isolated manifestation of CPPD. The diagnostic gold standard is a cervical CT scan with particular focus on the C1–C2 region.

 

Conclusions: While CDS is rare, awareness of presentation is important as it can significantly complicate the rehab course. In addition to ordering the diagnostic work up, if there is suspicion of CDS, we recommend holding therapy until the patient is evaluated by rheumatology.