Gastroparesis. I have never seen a death due to gastroparesis alone. Theoretically, the resulting dehydration from the vomiting could kill you, if not treated appropriately, particularly if you have other disease conditions. Gastroparesis usually involves chronic vomiting due to paralysis of the stomach which leads to dehydration, and often requires hospitalization to manage the dehdyration and salt losses.
No. Have not heard of this being a lethal condition. Medications can frequently treat but if they fail, a laparoscopic gastric pacemaker or laparoscopic sleeve gastrectomy are surgical options that have met with good success rates.