Our review includes 6 cases.
These are examples used to illustrate imaging findings of Crowned Dens Syndrome and its differential diagnoses.
All patients presented with acute,
non-traumatic neck pain.
CASE 1
92-yr-old female presented to A&E with pyrexia,
suspected stroke and urosepsis.
No history of fall or trauma.
White cell count was 13 x 109/L and C-reactive protein was 215mg/L.
Clinical examination found exquisite tenderness at C2-C3 and inability to rotate the neck laterally.
A CT was requested to exclude a fracture (Fig.
4).
Fig. 4: XR Wrist (image 1): chondrocalcinosis of the TFCC.
CT cervical spine axial (image 2 and 3) and sagittal (image 4): linear and mottled retro-odontoid calcifications. No frank erosions and no fracture.
A fracture was excluded at CT but calcification around the odointoid peg was reported.
A previous wrist radiograph showed chondrocalcinosis at the TFCC.
Due to increasing neck pain,
the orthopaedic team requested an MRI to rule out an occult injury,
cord compression or nerve root impingement.
MRI showed no evidence of cord compression or spinal canal stenosis.
Multilevel degenerative exit foraminal narrowing was identified (not shown in pictures).
Fig. 5: T1 and T2 weighted sagittal (top left and top right respectively) and T2*: peri-odontoid material of intermediate signal intensity with minimal irregularity of the odontoid peg.
T1 and T2 weighted images in the sagittal and axial plane confirm the presence of peri-odontoid material of intermediate signal intensity with minimal irregularity of the odontoid peg but no frank erosions and no fracture (Fig.
5).
After discussion with the rheumatology team,
the patient commenced a low dose of steroids and her symptoms improved.
Final diagnosis: acute presentation of CPPD deposition with Crowned Dens Syndrome.
CASE 2
A 70-yr-old female patient is referred from the walk-in centre with sudden onset of severe neck pain and pyrexia.
At clinical examination,
she is found to have pain and swelling in her hands,
wrists and ankles.
C-reactive protein is 88mg/L.
She is admitted to the rheumatology ward with suspected inflammatory arthritis.
Fig. 6: XR cervical spine - lateral view: erosion around the dens (arrow) and pre-vertebral soft tissue swelling (double arrow).
The initial radiograph shows erosion around the dens and pre-vertebral soft tissue swelling (Fig.
6).
A CT of the neck with contrast is requested to rule out an abscess as both WCC and C-reactive protein have increased to 13x109/L and 179mg/L respectively.
Fig. 7: CT sagittal view with bone and soft tissue window: calcification posterior to the odontoid process (arrows) with a small well defined erosion (blue circle).
CT shows faint calcification posterior to the odontoid process with a small erosion with well defined edges.
Underlying inflammatory arthropathy or crystal deposition diseases is suspected and a soft tissue abscess excluded (Fig.
7).
An MRI is requested to exclude a cord compression and rule out discitis, when the patient developes new weakness in her upper limbs.
Fig. 8: T2-weighted (left) and T1-weighted (right) sagittal images: intermediate to low signal material surrounding the peg and bulging into the spinal canal.
T1 and T2-weighted images show intermediate to low signal material surrounding the peg and bulging into the spinal canal (Fig.
8).
Post contrast images did not show enhancement of the retro-odontoid signal and no features of discitis (Fig.
9).
Fig. 9: T1-weighted sagittal (left): peri-odontoid intermediate signal (blue circle). Post contrast T1-weighted sagittal (middle) and axial (right) did not demonstrate contrast enhancement.
Review of previous imaging demonstrated localized erosions in the mid-foot,
calcifications in the plantar fascia and severe unilateral hip arthropathy (Fig.
10).
There was also a past history of psoriasis.
Fig. 10: XR Foot - AP view (left): localized, marginal erosions at the first TMTJ (blue circle).
XR Ankle - lateral view (top right): calcifications in the plantar fascia (arrow).
XR Pelvis - AP view (bottom right): severe unilateral right hip arthropathy (blue circle).
The patient started treatment with 10 mg of prednisolone and her symptoms improved with reduction of inflammatory markers within a few days.
Final diagnosis: Sero-negative RA or psoriatic arthritis with features of co-existing CPPD deposition and CDS.
CASE 3
An 85-yr-old male usually fit and well,
is admitted with suspected urinary tract infection.
He complains of neck pain.
Laboratory tests reveal high inflammatory markers (CRP 198 mg/L and WCC 19x109/L) and negative rheumatoid factor.
An MRI is requested to rule out discitis or para-spinal abscess due to increasing neck pain.
Fig. 11: XR Cervical spine (image 1): erosive changes around the odontoid peg (blue circle).
T1-weighted and T2-weighted sagittal (image 2 and 3): bone erosion, oedema and irregularity of the odontoid peg (bleu circle). Superior migration of the odontoid peg in the foramen and distortion of the spino-medullary junction.
The MRI shows a gross abnormality involving C1 and C2; there is bone erosion,
oedema and irregularity of the odontoid peg.
There is also superior migration of the odontoid peg in the foramen and distortion of the spino-medullary junction (Fig.
11).
A CT was suggested to better define anatomy and exclude a fracture of C1.
The CT (Fig.
12) confirms erosive changes of the odontoid peg and its base.
These have relatively well defined margins indicative of a long-standing process.
Associated soft tissue density along the dorsal aspect of the odontoid indenting the ventral aspect of the cord.
Subtle retro-odontoid calcification coexist.
Fig. 12: CT Sagittal and axial: erosive changes of the odontoid peg and its base (blue circle and arrows on image 2, 3 and 4). These have relatively well defined margins indicative of a long-standing process. Associated soft tissue density along the dorsal aspect of the odontoid indenting the ventral aspect of the cord (image 1, blue arrows). Subtle retro-odontoid calcification coexist (dashed white arrows on image 3 and 4).
Reviewed by orthopaedic spinal team the patient was not deemed fit for any intervention and was then started on 30-40 mg/day prednisolone with gradual reduction of prednisolone to 10 mg/day. Her responded well to steroids and both inflammatory markers and pain improved.
Final diagnosis: Crowned Dens Syndrome,
presumably exacerbated by recurrent UTI.
CASE 4
An 85-yr-old female patient presented acutely with severe headache and neck pain.
No associated neurological symptoms.
No history of fall or trauma.
An urgent CT head out-of-hours excluded an acute intracranial event but noted pronounced bone erosions around the odontoid peg and anterior arch of C1 suggestive of erosive arthropathy (Fig.
13).
Rheumatology referral is organized and an MRI requested.
MRI confirmed very abnormal appearances of the odontoid peg with stenosis of the foramen magnum.
There is soft tissue material mildly enhancing on post-contrast images surrounding the odontoid peg and atlanto-axial subluxation (Fig.
13).
Laboratory tests showed Rheumatoid Factor at 140 U/ml and CRP at 11mg/L.
Fig. 13: Sagittal STIR (image 3), T1-weighted (image 1) and T2-weighted (image 2): abnormal appearances of the odontoid peg. Atlanto-axial subluxation and stenosis of the foramen magnum.
Axial T1-weighted post contrast (image 5): enhancing soft tissue material surrounding the odontoid peg.
CT axial, bone window (image 4): bone erosions around the odontoid peg and anterior arch of C1 (blue circle).
The case was discussed with spinal team and the patient was deemed not suitable for any intervention.
Final diagnosis: Rheumatoid arthritis of the cervical spine with erosive changes,
pannus and instability.
CASE 5
A 71-yr-old male was admitted acutely with upper cervical spine and occipital pain.
Mildly increased C- Reactive Protein and white cell count at 8.5mg/L and 13x109/L respectively.
No history of trauma or falls.
Plain radiograph at admission shows degenerative changes only (Fig.
14).
Initial MRI done to rule out neural compression and infection shows a posterior smooth erosion of the odontoid peg with a trace of fluid around it (Fig.
14).
A small bone fragment adjacent to the tip of the peg is also reported.
Multilevel neural foraminal narrowing is noted but no cord compression or spinal canal stenosis.
No signs of discitis or paravertebral abscess.
A CT done to exclude a fracture of the peg demonstrated marginal osteophytes,
joint space narrowing with a small loose body (Fig.
14).
Fig. 14: XR Cervical spine - Lateral view (top left): no obvious abnormality at the cranio-cervical junction.
Sagittal T2-weighted (top right): posterior smooth erosion of the odontoid peg with a trace of fluid around it (blue circle). No signs of discitis or paravertebral abscess.
Sagittal and axial CT - bone window (bottom left and right): marginal osteophytes, joint space narrowing and a small loose body.
Final diagnosis: Osteoarthritis at the atlanto-axial joint.
CASE 6
A 72-yr-old female patient presents with pyrexia,
acute severe sharp neck and occipital pain.
She is unable to move neck without severe pain.
No focal neurology at clinical examination.
No history of trauma. A radiograph of the cervical spine is requested.
The plain film shows thickened pre-vertebral soft tissue (Fig.
15) and recommends cross-sectional imaging.
A CT of the cervical spine with contrast is organized.
The patient is intubated.
Fig. 15: XR Cervical spine - lateral view: preveretebral soft tissue swelling (image 1, double arrows).
CT Sagittal bone and soft tissue window: bone destruction of the peg, body and anterior arch of C1 and clivus (image 2, blue circle). Posterior slip of the odontoid with soft tissue narrow the foramen magnum and spinal canal.
Fluid and a soft tissue mass surround the C1-C2 articulation and cranio-cervical junction (image 3, white dashed arrows).
CT (Fig.
15 and 16) shows bone destruction with sclerosis and loss of height of the peg,
body and anterior arch of C1; further bone destruction of the clivus and occipital condyles. Posterior slip of the odontoid with soft tissue narrow the foramen magnum and spinal canal.
Fig. 16: CT axial - bone and soft tissue window: bone destruction of the peg, body and anterior arch of C1 (blue circle; bone window).
Fluid and a soft tissue mass surround the C1-C2 articulation (blue arrows: soft tissue window)
Fluid and a soft tissue mass surround the C1-C2 articulation and cranio-cervical junction.
An urgent MRI with contrast was requested by the spinal team to define further management.
Fig. 17: Sagittal T2-weighted (image 2): a destructive process around the cranio-cervical junction; high signal surrounds the odointoid process (dashed white line), encroaching on the spinal canal calibre at C1-C2; extensive pre-vertebral oedema/inflammatory changes (blue arrows). The upper spinal cord is flattened and compressed.
Sagittal T1-weighted (image 1), sagittal and axial T1-FS post contrast (image 3, 4 and 5): loss of T1 weighted signal and intense enhancement of the clivus, odontoid peg and body of C2 (white dots; image 1 and 3). Fluid surrounds the peg (arrows on image 4 and circle on image 5). A large inflammatory phlegmon is present with pre-vertebral and ventral epidural compressing the cord (image 3; blue lines).
The MRI (Fig.
17) shows a destructive process around the cranio-cervical junction with destruction of the atlanto-occipital and atlanto-axial joints.
Loss of T1 weighted signal and intense enhancement of the clivus,
odontoid peg and body of C2. A large paravertebral inflammatory phlegmon is present with prevertebral and ventral epidural component encroaching on the spinal canal calibre at C1-C2 and narrowing the naso-pharinx.
The upper spinal cord is flattened and compressed.
The patient deteriorated after conservative treatment with IV antibiotic and underwent occipital C2-C4 fusion,
two days later. Follow up imaging (Fig.
18) demonstrated decompression of the cervico-medullary junction and satisfactory bony alignment at the cranio-cervical junction,
after surgery.
Fig. 18: Sagittal T2-weighted: pre-operative (left) image with encroachment of cervico-medullary junction and post-operative image (right) with satisfactory decompression of the cervico-medullary junction.
Final diagnosis: extensive C0-C1 and C2 osteomyelitis with large epidural abscess/phlegmon and cord compression.