Chiari I - Idiopathic Intracranial Hypertension Association After Failed Posterior Fossa Surgery. Case Report

Objectives: Several papers have been published relating the Idiopathic Intracranial Hypertension Syndrome (HTII) to the Arnold Chiari type I malformation (AC1M). Both entities have clinical and demographic similarities, a poorly defined etiology and, sometimes common therapeutic posibilities. A correlation between both entities has been suggested, especially in a subgroup of patients in whom posterior fossa decompression surgery fails. With regard to a case, we reviewed the literature and proposed our hypothesis about the origin of Chiari-HTII syndrome and its therapeutic possibilities. Case presentation: A 41year-old patient with mild obesity, menstrual abnormalities and empty Sella Turcicae, was operated on with an AC1M associating basilar impression and syringomyelia causing all together a centromedullary syndrome. After posterior fossa decompression surgery and successful arthrodesis, she improved in the immediate postoperative period. Nevertheless, she soon developed symptoms of intracranial hypertension (ICH), and showed increased opening pressure in lumbar puncture compatible with HTII syndrome. A ventriculoperitoneal shunt (VPS) was implanted with clinical improvement and 12 months later the syringomyelia was absent on in the magnetic resonance (MRI). Conclusion: The Chiari I-HTII syndrome is described as the coexistence of ICH symptoms after failed posterior fossa surgery, in patients with no flow MRI anomalies, and increased opening pressure at the lumbar puncture. In our experience, both entities seem to overlap in a common syndrome and must be taken into account, especially in patients with atypical onset of symptoms or patients in whom conservative treatment fails.