We have previously discussed Chiari mimic in the setting of intracranial hypotension secondary to spinal CSF leak.
spinalcsfleak.org/mimic-chiari/
Chiari malformation is congenital, but descent of the cerebellar tonsils can be secondary to other disorders, including but not limited to intracranial hypotension from spinal CSF leaks. It can also be congenital and exacerbated by other factors such as a spinal CSF leak. This complexity impacts treatment and outcomes.

Spontaneous spinal CSF leaks are often related to an underlying heritable disorder of connective tissue (HDCT). These same HDCTs are associated with a higher prevalence of Chiari. In a patient with a HDCT, a congenital Chiari may exist or a spontaneous spinal CSF leak may result in an “acquired” Chiari or a preexisting Chiari may be exacerbated by a spinal CSF leak. There may be other factors involved. It isn’t always straightforward.

Mark Luciano, MD of Johns Hopkins in Baltimore, MD, has recently given a talk in association with the Chiari & Syringomyelia Foundation that may help you to better understand these issues. The video is shared with permission from Dr. Luciano and the Chiari & Syringomyelia Foundation.

vimeo.com/163167158

You can also learn more about Chiari from the Chiari & Syringomyelia Foundation at csfinfo.org

Remember that when cerebellar tonsillar descent that looks like Chiari is found, when the underlying cause or causes and complicating factors are better understood, management is impacted to achieve better outcomes. When cerebellar descent is secondary to a spinal CSF leak in entirety or as a contributing factor, then treatment of the underlying CSF leak might be the most appropriate first step.