Do you have one? These are killers if neglected. You'll either have a hemorrhagic stroke, or become demented from the wild changes in blood pressure, or have your heart muscle fail from the excess catecholamines, or get heart failure from hypertension. None of these are pleasant. If you are offered surgery, take it.
Yes. If not properly diagnosed and treated appropriately, it can kill you. This is a special disease. You should have an endocrinologist on the case and need to use surgical team who are experienced in treating this disorder.