Chiari I malformation with associated hydrosyringomyelia and Klippel-Feil syndrome
Patient Data
- cerebellar tonsillar herniation under the basion-opisthion line of about 1.6-cm with crowding of the cerebrum and cervicomedullary junction at the foramen magnum and disappearance of the cisterna magna, consistent with Chiari I malformation
- abnormal flattening of the skull base is seen, due to hypoplasia of the clivus
- atlantooccipital assimilation
- congenital C5 and C6 vertebral body fusion
- syrinx from C4 to C7 with no evidence of a solid component (evaluation with contrast would be helpful)
- no obvious features in the part of the brain imaged to suggest a Chiari II malformation.
Case Discussion
Chest X-ray is recommended to assess other features of Klippel-Feil syndrome: e.g. Sprengel's deformity, omovertebral bone. An ultrasound abdomen to assess possible associated renal anomalies
This study shows a Chiari I malformation classified as stage 3 due hydrosyringomyelia.
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Classification of Chiari I:
stage I: asymptomatic (14-50%)
stage II: brainstem compression
stage III: hydrosyringomyelia
Two or more non-segmented cervical vertebrae are usually sufficient for diagnosis of Klippel-Feil syndrome. This case corresponds to type II.
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Classification of Klippel-Feil syndrome:
type I (9%): massive fusion of cervical and upper thoracic spine resulting in neurological impairment, frequent associated abnormalities
type II (84%): fusion of two or three vertebrae
type III (7%): cervical fusion with lower thoracic or lumbar vertebral fusion