Introduction: Syringomyelia is oftentimes associated with Chiari I malformation. Postulated pathophysiology of syrinx progression involves increased cervical subarachnoid pressure waves compressing the spinal tissue directing CSF into the spinal cord. While most cases of Chiari and syrinx are discovered at the time of diagnosis, we present a case documenting syrinx formation over the course of 4 days in an incidentally found Chiari I malformation.
Methods: We present a 16 year old who was suffering from fever and headache for 1 week, diagnosed with viral meningitis by CSF analysis. His work up included a CT of his brain which showed a Chiari I malformation. MRI imaging confirmed a 9 mm tonsillar herniation and no evidence for syrinx. Despite treatment for his meningitis, his headache worsened and he developed a myelopathic gait. Repeat imaging studies showed mild progression of hydrocephalus, and new T2 signal hyperintensity within the cervical cord (figure 1). Subsequent spinal imaging showed worsening transependymal flow throughout the cord and a new small syrinx (figure 2). The patient was taken to the operating room for an endoscopic third ventriculostomy, and suboccipital craniectomy with C1 laminectomy and duraplasty for Chiari decompression.
Results: Imaging obtained on post-operative day 3 showed resolution of the syrinx, improved hydrocephalus and transependymal T2 signal in his cord, and increased CSF flow at the cervicomedullary junction. Symptomatically his headaches and myelopathy improved.
Conclusions: Our short term chronologic documentation of syrinx development lends support to the hypothesis that syrinx formation is associated with transependymal CSF flow through the spinal cord. With flow and velocity measurements underway on these serial images, we hope to gain more insight on the pathophysiology of both formation and progression of syrinx associated with Chiari I malformation.
Patient Care: A better understanding of the pathophysiology of syrinx formation and progression in Chiari I malformation can lead to 1) improvements in syringomyelia treatment in patients, 2) innovation of technology for either diagnosis or treatment, and 3) consideration of noval treatment options for recurrent symptomatic syringomyelia.
Learning Objectives: By the conclusion of this session, participants should be able to 1) Describe the physiology of CSF dynamics in Chiari I malformation and syrinx, and 2) Recognize MRI findings associated with syrinx formation in Chiari I malformation
References: Heiss JD et al. "Elucidating the pathophysiology of syringomyelia," J Neurosurg 91:553-562, 1999