Chiari-like malformation(CLM) is a condition in which a portion of the cerebellum descends through the foramen magnum affecting normal cerebral spinal fluid (CSF) flow.
The specific cause has not been determined; however, compressive malformations in the caudal fossa, volume mismatches between the cerebellum, brain stem and the caudal fossa, or the loss of the collagenous suspensory mechanism of the cerebellum may play a role in the cerebellar descent.
The subsequent changes in CSF flow dynamics result in hypertrophy of the regional meninges and eventual dural fibrosis.
The well documented change in CSF pressure and flow velocity can cause an abnormal accumulation of fluid within the substance of the spinal cord called a “syrinx” or syringomyelia in affected patients. Cervical hyperesthesia, pruritis and spinal lumbar hyperpathia are common clinical findings. It is considered to be a hereditary condition in Cavalier King Charles Spaniels and is commonly confused with many other conditions.
Chiari-like malformation affects small breed dogs and has been found in several cats.
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