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Crowned Dens Syndrome Presenting as Altered Mental Status

      Case

      A 77-year-old male presented from a rehabilitation facility for acute onset of confusion, significant pain in his neck and extremities, muscle rigidity and subjective fever. Comorbidities included Parkinson disease, Lewy body dementia, anxiety, depression and recent right shoulder surgery complicated by pulmonary embolism, for which he was started on apixaban. On admission, physical exam revealed severely limited range of motion in the neck, diffuse rigidity and weakness in all extremities, diffuse joint pain with movement of extremities and neck, and disorientation. His temperature was 37.6°C and initial investigations revealed a leukocytosis with white blood cell count of 14 thousands/microliter, erythrocyte sedimentation rate of 115 mm/h, C-reactive protein of 308 mg/L, urinalysis with numerous white blood cell counts, many bacteria and leukocyte esterase, with urine culture positive for Klebsiella pneumoniae and Enterococcus faecalis. An acute tick-borne panel was subsequently negative.
      Initial management included antibiotics for a urinary tract infection. In addition, given the recent initiation of tramadol for post-operative pain as well as chronic home medications including fluoxetine, trazodone, and sodium valproate and the initial presentation, serotonin syndrome was considered in the differential. However, despite initial management (antibiotics and cessation of potential offending medications) the patient's pain and confusion persisted, leading to alternative diagnoses other than urinary tract infection and serotonin syndrome being sought.
      As the pain was most prominent in the left shoulder and neck, a computed tomography scan of the cervical spine was pursued and revealed no acute fracture or traumatic subluxation. However, there was marked calcification of the soft tissue surrounding the retro-odontoid space (FigureA). Synovial fluid was aspirated from the left glenohumeral shoulder joint and revealed intra- and extra-cellular calcium pyrophosphate (CPP) crystals and plain radiographs of the knees also revealed chondrocalcinosis (FigureB). Therefore, given this constellation of findings, the diagnosis of crowned dens syndrome was made and prednisone 40 mg daily commenced, tapering by 10 mg every 5 days with rapid improvement and resolution of pain and confusion within 48 hours of initiation. At follow-up with Rheumatology approximately 2 weeks after completion of prednisone therapy, the patient remained pain free.
      Figure
      Figure(A) Computed tomography scan of cervical spine revealed marked calcification of the soft tissue surrounding the retro-odontoid space. (B) Plain radiographs of the knees revealed chondrocalcinosis.

      Discussion

      Crowned dens syndrome is a clinical and radiographic entity that refers to crown-shaped CPP crystal deposition around the odontoid process leading to acute neck pain.
      • Bouvet JP
      • Le Parc JM
      • Michalski B
      • et al.
      Acute neck pain due to calcifications surrounding the odontoid process: the crowned dens syndrome.
      It is a relatively uncommon condition and its incidence is not well established, although in a Japanese cohort, the incidence of crowned dens syndrome in individuals presenting with acute neck pain was 2%.
      • Goto S
      • Umehara J
      • Aizawa T
      • Kokubun S
      Crowned dens syndrome.
      Crowned dens syndrome can be easily mistaken for other conditions such as polymyalgia rheumatica, giant cell arteritis, or meningitis, because in addition to neck pain, it is typically accompanied by fever and an inflammatory response.
      • Ledingham D
      • Cappelen-Smith C
      • Cordato D
      Crowned dens syndrome.
      Additional challenges in diagnosis include its heterogeneous presentation with signs and symptoms potentially also including positive Kernig sign, positive Brudzinski sign, or both; malaise; and occipito-temporal as well as mandible pain and weakness with inflammatory pain of the shoulder girdle.
      • Salaffi F
      • Carotti M
      • Guglielmi G
      • Passarini G
      • Grassi W
      The crowned dens syndrome as a cause of neck pain: clinical and computed tomography study in patients with calcium pyrophosphate dihydrate deposition disease.
      The gold standard investigation to assist in diagnosis of crowned dens syndrome is computed tomography scan of the cervical spine revealing crown-like calcification surrounding the odontoid process as in the case described.
      • Takahashi T
      • Minakata Y
      • Tamura M
      • Takasu T
      • Murakami M
      A rare case of crowned dens syndrome mimicking aseptic meningitis.
      As also seen in the present case, the presence of chondrocalcinosis in other joints, a marker of CPP deposition in cartilage, and identification of CPP crystals in synovial fluid can provide useful adjunctive information.
      • Zhang W
      • Doherty M
      • Bardin T
      • et al.
      European League Against Rheumatism recommendations for calcium pyrophosphate deposition. Part I: terminology and diagnosis.
      Further supportive evidence can include the presence of inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate, an absence of traumatic injury and exclusion of other potential diagnoses.
      • Goto S
      • Umehara J
      • Aizawa T
      • Kokubun S
      Crowned dens syndrome.
      In previous case reports, treatment with nonsteroidal anti-inflammatory drugs, colchicine or corticosteroids has been reported to result in quick resolution of symptoms.
      • Aouba A
      • Vuillemin-Bodaghi V
      • Mutschler C
      • De Bandt M
      Crowned dens syndrome misdiagnosed as polymyalgia rheumatica, giant cell arteritis, meningitis or spondylitis: an analysis of eight cases.
      ,
      • Sato Y
      • Yasuda T
      • Konno S
      • Kuwayama A
      • Komatsu K
      Pseudogout showing meningoencephalitic symptoms: crowned dens syndrome.
      In this case, the patient responded quickly to corticosteroid, which was chosen because nonsteroidal anti-inflammatory drugs were contraindicated due to the patient being on anticoagulation. Therefore, it is crucial to have crowned dens syndrome in the differential of patients who present with acute neck pain who have risk factors or prior evidence of CPP disease.

      References

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