Presyrinx in children with Chiari malformations.

BACKGROUND: Presyrinx is a reversible state of spinal cord edema caused by alterations in CSF flow dynamics. Only three pediatric cases have been reported previously. We describe the clinical and radiologic features of presyrinx in six pediatric patients.

METHODS: We electronically searched pediatric spine MRI reports generated at our institution from January 1995 to April 2007 for the keyword "presyrinx" and identified six patients with this radiologic diagnosis. We reviewed the neuroimaging studies and medical records for information regarding symptoms, treatment, and outcome.

RESULTS: Of six patients identified with presyrinx, four had a Chiari I malformation and two had a Chiari II malformation. The MRI characteristics of the presyrinx included T2 prolongation, mild indistinct T1 prolongation, and cord enlargement without frank cavitation. Cine phase-contrast MRI studies were performed in three patients and showed severely diminished or absent CSF flow at the foramen magnum. Five patients underwent surgical decompression. All three patients with postoperative spine imaging showed restoration of CSF flow and resolution of the presyrinx. Symptoms of chronic or acute myelopathy attributable to the presyrinx were present in two patients. These symptoms resolved postoperatively.

CONCLUSIONS: Chiari I and II malformations obstructing CSF flow at the craniocervical junction may cause presyrinx in children. Presyrinx should be considered in the differential diagnosis of chronic or acute myelopathy in patients at risk for abnormal CSF flow dynamics.