Description

A 69-year-old man with hyperlipidaemia presented to the emergency department with a 4-day history of new onset pain in the neck. The pain was severe (rated 9/10 in severity), constant, localised to the base of the skull and was associated with significant restriction of neck motion; any movements resulted in dramatic worsening of the pain. He also reported subjective fevers at home. He did not report trauma, photophobia, phonophobia, nausea, vomiting, insect bites, visual disturbances, trouble swallowing or speaking, jaw claudication or morning stiffness. There were no sick contacts. He did not have pain at any other sites. He had tried some topical diclofenac gel for the past 2 days without much relief. His only scheduled medication was atorvastatin.

On physical examination, his temperature was 38.1°C, blood pressure was 128/82 mm Hg, heart rate was 82/min and respiratory rate was 14/min. He was visibly trying not to move his neck, and the range of passive motion in the neck was restricted. Systemic examination including detailed neurological and musculoskeletal examinations were within normal limits; there was no papilloedema.

The differential diagnoses were broad at this time, including musculoskeletal causes, meningitis and giant cell arteritis. Laboratory analysis revealed a neutrophilic leucocytosis (white cell count 15.3 x 10⁹/L, 92% neutrophils) and elevated inflammatory markers (erythrocyte sedimentation rate 40 mm/h, C-reactive protein 12 mg/dL). Blood cultures were drawn (later reported no growth) and a lumbar puncture was performed which was unremarkable. A plain radiograph of the neck revealed mild degenerative joint changes. A non-contrast CT scan of the cervical spine showed calcification posterior to the odontoid process (figure 1). A diagnosis of crowned dens syndrome was made, and scheduled ibuprofen therapy was initiated and the patient discharged. At a follow-up 1 week later, the patient reported near-complete relief of symptoms, and ibuprofen was discontinued.

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Figure 1

Axial view of a non-contrast CT scan of the cervical spine performed on a patient presenting with excruciating neck pain with any movement. Note the granular calcification posterior to the odontoid process (red arrow), consistent with the crowned dens syndrome.

Crowned dens syndrome is a rare, inflammatory manifestation of calcium pyrophosphate crystal deposition disease, first described in 1985.1 It occurs most commonly in the elderly (age >70 years).2 It usually presents with acute or recurrent, severe, axial neck pain. Pain is usually localised to the base of the skull, with restricted neck motion (especially rotation).2 Fevers and elevated inflammatory markers are typical. Chondrocalcinosis, or deposition of hydoxyapatite crystals in any of the periodontal ligaments surrounding the odontoid process (also called the ‘dens’) of the axis (second cervical vertebra) gives the appearance of a ‘crown’ surrounding it. This is usually evident on CT scans of the cervical spine.3 Plain radiographs may not demonstrate this finding.

The acute presentation and combination of neck pain, fever and elevated inflammatory markers can be alarming for the presence of polymyalgia rheumatica, giant cell arteritis, meningitis or inflammatory spondylarthrosis such as rheumatoid arthritis.2 3 Clinicians must maintain a strong suspicion to be able to diagnose this condition. It generally responds favourably to short courses of non-steroidal anti-inflammatory drugs or colchicine.2 3 Complications are rare, but cervical cord compression can occur due to developing inflammatory pannus.