Case Presentation: A 95-year-old man with hypertension, benign prostatic hyperplasia, irritable bowel syndrome, and a recent herpes zoster ophthalmicus infection presented to the emergency department (ED) with fevers. The patient had been well until 3 days prior, when he developed a temperature of 103°F followed by severe pain in the neck radiating to both shoulders. On arrival his temperature was 103.1°F, heart rate 58, blood pressure 123/46, respiratory rate 17, and oxygen saturation 98% on room air. Physical exam revealed tenderness to palpation along the cervical spine with decreased range of motion. Laboratory results showed normal white blood cell count and elevated inflammatory markers, including C-reactive protein of 10.5 mg/dl and erythrocyte sedimentation rate of 71 mm/hr. A lumbar puncture was performed, and cerebrospinal fluid analysis was unremarkable. Magnetic resonance imaging (MRI) of the cervical spine revealed nonspecific prevertebral edema and epidural enhancement, raising concern for soft tissue infection and early developing phlegmon. The recent herpes zoster infection was considered to be a potential portal of entry for a bacterial infection, and intravenous antibiotics were initiated. Neck pain continued to worsen, and fever persisted. The patient then developed sudden onset atraumatic left elbow and knee pain, leading to knee arthrocentesis. Synovial fluid cultures were negative, but positively birefringent rhomboid-shaped crystals were observed. Computer tomography (CT) of the cervical spine revealed calcifications of the periodontal ligaments around the second cervical vertebra’s odontoid process, also called dens. Antibiotics were discontinued and the patient was started on high-dose steroids. This resulted in the resolution of fevers, improvement in neck pain and range of motion, and a decrease in inflammatory markers. The patient was diagnosed with calcium pyrophosphate crystal deposition (CPPD) disease of the spine, specifically the so-called crowned dens syndrome.
Discussion: CPPD disease, also known as pseudogout, is a metabolic arthropathy caused by crystal deposition in connective tissues and usually affects large joints. Crowned dens syndrome (CDS) is a rare radio-clinical syndrome characterized by severe acute neck pain and stiffness, fever, elevated inflammatory markers and CPPD around the atlanto-axial joint. We describe a case of CDS, initially treated as a purulent infection based on the MRI scan. Notably, MRI does not visualize calcifications well, and CT might be necessary. Diagnosis of CDS remains challenging as the imaging findings are not absolutely specific. Calcifications along the spinal column can sometimes be seen in asymptomatic individuals. Therefore it needs to be carefully assessed if presence of characteristic crown-like deposits on the dens is indeed the cause of the presentation. Symptoms overlap with polymyalgia rheumatica and meningitis, which frequently need to be ruled out. Treatment involves non-steroidal anti-inflammatory drugs (NSAIDS), colchicine, or systemic steroids in cases with polyarthritis.
Conclusions: Acute neck pain is a common complaint in the ED and when accompanied by fever it often leads to a hospital admission. Hospitalists should consider spine involvement of CPPD disease as a differential diagnosis, especially in elderly patients with polyarthritis. Early diagnosis can help to avoid invasive investigations and prevent prolonged hospital stays with unnecessary broad-spectrum antibiotic exposure.