A 76-year-old female was admitted from an outside hospital for concern for osteomyelitis of her cervical spine. She had previously had a week of neck pain with limited range of motion due to pain. She was treated for E. coli sepsis following positive blood and urine cultures, but her neck pain persisted. Upon transfer, lab results revealed ESR of 39 mm/hr and CRP of 20.4 mg/dL. MRI results showed no findings to suggest osteomyelitis, but revealed marked soft tissue swelling at the craniocervical junction along the margin of the odontoid process, as well as fluid collection at the C4-C5 level. A CT guided aspiration was performed which showed positive birefringent rhomboid crystals. The diagnosis of CPPD was made, and the patient was started on naproxen and colchicine. One day later her pain was markedly reduced with improved mobility.
Discussion:
This report describes a rare but well-documented presentation of CPPD. During the presentation of this case, several things were included in the differential. Given the concerns from the outside hospital and prior positive blood cultures, osteomyelitis or other infective causes (abscess) were at the top of the differential diagnosis. CPPD was only considered after CT-guided biopsy of the C4-C5 fluid pocked revealed pyrophosphate crystals.
CPPD is a well-known cause of arthritis, formerly referred to as psuedogout, that has several different presentations. However, one rare form is crowned dens syndrome, defined as CPPD involveing the atlanto-axial joint, specifically the odontoid process. Radiographs typically show calcification of the cruciform ligament as well. CDS typically causes acute cervical pain and stiffness, fever, and headache. In some cases, the stiffness and limited range of motion is the predominating symptom, confusing the diagnostic picture. Rarely, it can present with neuropathy by compressing spinal nerve roots. Laboratory results are non-specific, but typically involve elevated inflammatory markers, specifically ESR and C-reactive protein and elevated WBC. This can create a confusing clinical picture, as spondyloarthritis, meningitis, polymyalgia rhuematica, giant cell arteritis, and several other disease processes can present similarly. These syndromes are not only more common and well-known, but are also much more serious diseases and require a high degree of clinical suspicion when evaluating, therefore are often higher on the differential than crowned dens syndrome.
While crowned dens syndrome is rarely reported, there is evidence to suggest that it is frequently misdiagnosed, as the symptoms can masquerade as other more frequent and often more clinically serious disease processes. Furthermore, most cases fully resolve after a short course of NSAIDS, steroids, or colchicine, which are often used to treat non-descript muscle pain in the acute setting. Tajima et al. proposes this further reduces the incidence of crowned dens syndrome, as many cases are treated without being diagnosed as such. This case report hopes to raise the awareness and clinical suspicion for crowned dens syndrome in the hospitalist or internist given the appropriate context.
Conclusions:
Crowned dens syndrome is rare but likely under-diagnosed condition that can easily be mistaken for several other more serious conditions. We present a case that presented in this way, and propose that CDS should be considered by the hospitalist in the differential for acute neck pain.