025. A CASE OF CROWNED DENS SYNDROME: AN IMPORTANT CAUSE OF NECK PAIN

Abstract

Background: The crowned dens syndrome (CDS) is an important, underrecognized cause of neck pain caused by crystal deposition disease affecting the cervical spine. It is characterized by severe neck pain and stiffness, biological inflammatory response, a radio-dense halo or crown of crystals around the odontoid peg on computed tomography (CT), and dramatic response to non-steroidal antiinflammatory drugs (NSAIDs) or glucocorticoids. It is usually caused by calcium pyrophosphate or hydroxyapatite crystals, and occurs more commonly in patients with crystal deposition disease at other sites. Method(s): We present a case of CDS in an elderly lady, demonstrating rapid resolution with NSAIDs. This 79 year old lady presented to her General Practitioner (GP) with a short history of severe inter-scapular pain and malaise, with elevated C-reactive protein (158 mg/L). She had no significant past medical history except one previous episode of pseudogout affecting her hand. She was referred to the acute chest pain clinic, where a cardiac cause was ruled out and it was noted that inter-scapular pain had evolved into neck pain and stiffness. Investigations revealed normocytic, normochromic anaemia (haemoglobin 93 g/L), mildly raised alkaline phosphatase (161 IU/L, increase in bone fraction) and alanine transferase (78 IU/L), and elevated CRP at 158 mg/L. Troponin T, myeloma screen, lipid profile, renal function, electrolytes and the remainder of her full blood count were all normal. A blood film demonstrated a reactive picture. Cervical spine X-ray showed degenerative changes. Result(s): The patient was given a trial of NSAIDs and referred for urgent review in rheumatology outpatients. She reported rapid resolution, upon treatment with naproxen, of a broad range of symptoms including fatigue, nausea, anorexia, breathing difficulty and pain on deep inspiration, blurred vision and mental dullness. Repeat blood tests showed complete normalization of all parameters. The crowned dens syndrome was suspected, and CT of the cervical spine demonstrated the typical radio-dense ring around the odontoid peg. Conclusion(s): CDS is an important differential in the patient with neck pain. The typical presentation with severe pain and dramatic inflammatory response, often with fever and systemic symptoms, commonly raises suspicion of other inflammatory, infectious and malignant conditions including giant cell arteritis, polymyalgia rheumatica, bacterial meningitis, cervical myelopathy, spinal metastasis and localized infection. Patients can be exposed to unnecessary and invasive procedures, e.g. lumbar puncture, inappropriate treatment such as empirical antibiotics and prolonged glucocorticoid therapy and delay in diagnosis. While serious pathology may need to be excluded, particularly at first presentation, consideration should be given to empirical NSAID treatment and timely CT imaging, as making this diagnosis will help the clinician to minimize potential harm through unnecessary investigation and treatment.