Crowned Dens Syndrome
Crowned dens syndrome is an acute inflammatory condition characterized by severe neck pain and stiffness, often accompanied by fever and elevated inflammatory markers, resulting from the deposition of calcium pyrophosphate dihydrate (CPPD) or, less commonly, hydroxyapatite crystals in the ligaments surrounding the odontoid process (dens) of the axis (C2 vertebra). It is also known as acute pseudogout of the neck.
The calcifications typically form a "crown" or "halo" around the dens, most commonly involving the transverse ligament of the atlas, and are best visualized on cervical computed tomography (CT), which is the diagnostic imaging modality of choice due to its high sensitivity for detecting periodontoid calcifications.
Clinically, crowned dens syndrome presents almost exclusively in elderly patients, with a predilection for women, and manifests as acute onset of upper cervical pain, marked restriction of neck motion (especially rotation), and frequently fever and elevated CRP and ESR. The syndrome is often misdiagnosed as meningitis, polymyalgia rheumatica, or giant cell arteritis due to overlapping symptoms.
First-line treatment consists of NSAIDs, which typically result in rapid symptom improvement. Glucocorticoids and colchicine are also effective, particularly in refractory or severe cases. Recognition of crowned dens syndrome is essential to avoid unnecessary invasive procedures such as lumbar puncture or temporal artery biopsy.
