A Thirsty Swimmer: Medical Mystery Solved

Sharon Callahan was the subject of this week's Primetime: Medical Mystery. In 1985, she was a competitive college diver and pre-med student at a college in Virginia. She complained to her mother, Ginger Callahan, that she was exhausted and had been having hallucinations. Ginger contacted Dr. Fred Miller, a professor of medicine at Drexel University College of Medicine and Executive Vice Chair of the Department of Medicine, and asked him to see Sharon and try to diagnose her condition.

Below is a transcript of the story:

GINGER: "She was hallucinating when she would wake up in the middle of the night. [She] didn't recognize any of her roommates. It was very scary what she was telling me."

SHARON: "I went to the infirmary many times. They had told me it was stress that I was trying to take too much on. We want to a concert that was about an hour away from our dorm. On the way home, I had run out of water. I started having seizures. My hands would shake uncontrollably. I couldn't breathe. I was dizzy. I thought I was going to pass out. I got back and drank maybe a gallon of water right then and there, and the pain started going away. The pins and needles started lightening up. I started to breathe and relax again. At that point I realized there's something seriously wrong, and I called my mother."

GINGER: "Once she came to me, I knew she was scared or she would have taken care of it herself if she could. But his was beyond her."

SHARON: "It was at the point where I realized--I'm not gonna survive with this unless I get help for it or find out what is causing it."

DR. FRED MILLER: "When Sharon first came into my office. She was waking up in the middle of the night at least three or four times, maybe more. Sharon's sleep deprivation symptoms were profound."

SHARON: "The first thing that Dr. Miller said is he wanted to do a CAT scan to rule out the possibility of a brain tumor."

GINGER: "This diagnosis could be the end of everything. The end of her life, the end of my life, if anything happened to her. We were so stressed."

SHARON: "Based on all of my symptoms, I thought for sure that my life was over. When the results of the CAT scan came back it did show there was no brain tumor. In one sense I was relieved, on the other sense I was very depressed. It's been so many years that I was having these symptoms and no one was being able to figure it out. I was thinking at that point I was probably back to square one."

DR. MILLER: "She mentioned the fact that she was bringing glasses of water with her every time she got in a car. And I said, 'Why?' And she said, "Because I'm thirsty all the time."

SHARON: "When I was in college, I was known as the girl with the blue cup. During diving practice, after every dive that I did, I'd have to go and take a big gulp of water. It was beside my bed every night. It was in the car with me. It was pretty much attached to my hip. I was actually drinking about three gallons of water a day and because of that having to go to the bathroom every half hour, very 45 minutes."

DR. MILLER: "What would cause somebody to urinate a lot? And the diseases that would cause somebody to urinate a lot could be emanating from your kidney. It could be coming from certain hormones that affect your kidney. Your kidney itself could be abnormal. And then there are certain diseases where people just drink a lot of water?just because they feel compelled to drink a lot of water. They're under stress and that becomes a disease undo itself."

SHARON: "Dr. Miller did say he thinks he knows what is going on with me. The next step at that point would be a 24-hour water deprivation test to confirm what he was thinking."

DR. Miller: "You put somebody in a controlled environment and you actually stop them from drinking. This is a very scary test because people can urinate out huge volumes and become very dehydrated very quickly. Their blood pressure can go down and actually put them very much in harm's way."

SHARON: I couldn't go a ten minute walk without having water. I couldn't imagine going 24 hours without drinking water. After about an hour I started feeling sick. I was very dizzy, lightheaded. After about three hours I wasn't even able to stand up anymore. I believe I had lost five pounds of weight. Dr. Miller came in and he said we have to stop this test.

DR. MILLER: "After the water deprivation test we knew that Sharon had a lack of hormone that regulates the amount of urine you make a day that's known as central diabetes insipidus."

SHARON: "This is a very rare condition. The only way to get it would be if you hit your head exactly at one particular spot. Now it was up to Dr. Miller to figure out. "How did I get this condition?" He had asked me if I had ever bumped my head"

GINGER: "She said, 'No.' But I remembered four years earlier when she and I were in a really bad automobile accident."

DR. MILLER: "Somebody could hit their head and cause this type of disease. Sharon was able to essentially self-medicate herself with water. It wasn't curing the condition but it was essentially keeping her out of harm's way. Because she needed to get up all night to urinate, was disrupting her sleep pattern. And, in fact, I think the majority of the symptoms that actually brought Sharon into my office were ones of sleep deprivation. The therapy for Sharon's condition is to give her the hormone that's lacking from her brain."

SHARON: "Almost instantly after taking the medication, I started feeling better. By the fall when I went back to college, I felt like a kid again."