The doctors diagnosed Ménière's disease, a condition in which fluid pressure builds up in the inner ear. This syndrome causes the semicircular canals and motion detectors to become extremely sensitive, resulting in disorientation, dizziness, and nausea. There was no known cure, but in about 20 percent of cases the condition went away by itself. They prescribed diuretics in an attempt to drain the fluid from the ear. They also diagnosed glaucoma. An X-ray found a lump on his thyroid, and on January 17, 1964, surgeons at Hermann Hospital made an incision on his throat and removed 20 percent of his thyroid. The condition caused Shepard to be removed from flight status. Grissom and John Young flew Gemini 3 instead.