I also have been diagnosed with Chiari I malformation along with Arnold's Chiari. My spinal fluid was not leaving by head and caused similar symptons along with a constant pressure headache & eventually passing out if I sneezed, coughed, or gagged. I had a VP shunt inserted to allow my spinal fluid to leave my head. I eventually had to have Chiari Decompression surgery to relieve the headaches from returning when I sneezed, etc. Hope this information is useful.