Crowned Dens Syndrome!

Thanks to Eric and Naina for presenting the fascinating case of an elderly man who presented to the ER with acute, progressive shoulder and neck pain/stiffness that started after a visit to the dentist, found to have Crowned Dens Syndrome (???!!!) on CT imaging!

Clinical Pearls

  • The exam maneuvers we use to determine nuchal rigidity (neck stiffness, Kernig, Brudzinski signs) are not sensitive for meningitis.  Kernig and Brudzinski, when present, are highly specific.  Jolt accentuation is more useful as a screening tool because it is highly sensitive (>90%) but not very specific (~60%).
  • Make sure to check out Beers list when prescribing new meds for our geriatric patients.
  • For patients presenting with traumatic neck pain, consider using NEXUS or Canadian C spine rules to help you determine whether CT imaging is necessary.
  • Crowned Dens Syndrome is a rare finding in patients with CPPD and refers to deposition of calcium pyrophosphate crystals in and around the atlanto-axial articulation, which resembles a crown on CT imaging (image here).
  • The knee accounts for 50% of all acute CPPD flares.

Nexus criteria

  • No indication for CT if all of the following criteria are met
    • Absence of posterior cervical spine tenderness
    • Normal level of alertness
    • No evidence of intoxication
    • No abnormal neurologic findings
    • No painful distracting injuries

Canadian C-spine Rule

  • Step 1: CT indicated if any of the following are present:
    • Age > 65 years
    • Dangerous mechanism of injury
    • Paresthesias in the extremities
  • Step 2: Assess for low risk factors that allow for safe examination of the cervical spine range of motion
    • Simple rear-end mechanism
    • Sitting position in the ED
    • Ambulatory at any time
    • Delayed onset of neck pain
    • Absence of midline cervical spine tenderness
    • If ALL of these are present proceed to step 3
  • Step 3: Examine range of motion
    • Test active range of motion
    • Perform radiography in patients who are not able to rotate their neck actively 45 degrees both left and right. Patients able to rotate their neck, regardless of pain, do not require imaging


  • Umbrella term that covers
    • Pseudogout: acute synovitis/flare
    • Chondrocalcinosis: radiographic calcification in hyaline and/or fibrocartilage
    • Pyrophosphate arthropathy
  • Epi
    • 4-7% of adults
    • ~50% of those with radiographic findings are >84 years of age
  • Clinical manifestations
    • Asymptomatic (majority)
    • Acute CPP crystal arthritis: self limited acute or subacute attacks of arthritis involving one or several extremity joints. Knee is affected in over 50% of all acute attacks followed by wrists, shoulders, ankles, feet, and elbows.
      • Triggers: Trauma, surgery, severe medical illness. Abnormalities in serum calcium, magnesium, bisphosphonates, hemochromatosis.
    • Chronic CPP arthritis
      • Chronic inflammatory arthritis (5% of cases): resembles RA, multiple joints involved
      • Chronic osteoarthritis: Most prevalent form of symptomatic disease.
    • Severe joint degeneration
    • Spinal involvement
      • Crowned dens syndrome: rare, characterized by severe acute or recurrent axial neck pain, neck and shoulder girdle stiffness, and associated fever, elevated inflammatory markers, and CPP or calcium phosphate crystal deposition on CT in and around the atlanto-axial articulation
        • DDx would include PMR, Milwaukee shoulder (deposition of hydroxyapatite crystals, commonly seen in women >70 years of age) less frequently meningitis, cervical discitis, or inflammatory spondyloarthritis
        • Favorable response to NSAIDs and colchicine

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