"Dr. Cohen, Mrs. Harada is on the phone. She says Jennifer is dizzy and falling when she walks."
I was on my way into an exam room but ducked into my office to take the call. Jennifer was 3 years old, and nobody had yet figured out why she was developmentally delayed. But this sounded like something new--and worrisome.
"Hi, Karen. What's going on with Jennifer?"
"I don't know, Dr. Cohen. I brought her home from school and she seemed fine. She sat down to play, and when she stood up she couldn't walk right, like she was dizzy. And she just doesn't seem to be herself."
"Is she breathing all right?" First things first. My mind started going over the possibilities.
"Yes, she seems comfortable, just . . . well, dizzy."
"Did she fall or hurt herself?"
"No."
"Could she have gotten into any medications?" Poisoning is always a consideration with a toddler.
"No, I can't think of any."
I certainly needed to see her, but it didn't sound as if she needed an ambulance.
"Why don't you bring her right in and I'll check her out."
Jennifer was the first child of Karen and Mike Harada, both teachers. Karen was in her thirties when Jennifer was born, and she was a bit anxious about the baby. It didn't help that her child was born with developmental dysplasia of the hip. Infants with this condition require a few months in a special harness that helps guide their hips into the appropriate alignment. Given this condition, her parents weren't surprised when Jennifer was slow to learn to walk. But in the months following her first birthday, her parents began to realize she was developmentally delayed. At 18 months, she still hadn't begun to walk, she didn't speak, she wouldn't help when she was being dressed or undressed. She acted more like a 9-month-old than an 18-month-old.
I ordered a number of lab tests, including thyroid function, blood chemistry, and chromosome analysis: no answers. A scan of her brain offered little more. I wasn't surprised: For many developmental delays, no specific cause is ever found.
As the months went on, Karen and Mike learned to deal with the frustrations of living with a toddler who was different. Jennifer looked like a healthy child, but she did not talk or run or draw like a normal child. (She did, however, learn to walk when she was 2.) Of even greater concern was her interpersonal behavior. Jennifer played only by herself, and her play was rudimentary and stereotyped, not imaginative like other toddlers'. She didn't show affection, and she didn't seek out her parents when she was upset. I suspected that Jennifer was autistic. She fit many of the criteria: slow mental development, disordered or absent speech, and severe deficits in social interaction. But autism is not a disease. What are now called autism spectrum disorders are simply patterns of development that share some common features. While some autistic children have specific medical conditions, for most the cause is unknown. And autism is very resistant to treatment. Some children have shown remarkable responses to approaches as diverse as intensive behavior therapy, antidepressants, or even high-dose vitamins, but most autistic children remain mysteriously and frustratingly out of reach.
Breathless and worried, Karen brought Jennifer into the exam room. Clearly, something unusual was going on. Jennifer walked with a lurch, and she fell several times. She tended to turn her head a little bit to the right when she looked at something, and I noticed that she used her left hand but not her right. I could see why her mother had been so concerned.
"When did you first notice this?" I asked, while I watched Jennifer and tried to make some sense out of what I was seeing.
"After I brought her home from school. The teacher said she'd had a good day, and she was fine when she sat down to play. But as soon as she stood up, she was acting just like this."
I had an idea. I had to think way back to my neurology rotation in medical school—some 20 years earlier—but it seemed to make sense. "I think this little girl has had a stroke," I said to myself. To test my hunch, I got Jennifer's attention and then showed her a toy, using my right hand. She turned to look at it while it was still off to the side. But when I tried again with my left hand, she didn't notice the toy until it was in front of her.
I had just demonstrated that Jennifer had a visual-field cut: Because of damage to her brain, she couldn't see anything to her right. Putting this together with the weakness of her right arm and leg, I knew that something had suddenly injured the left side of her brain. The most likely cause, though rare in children, was a cerebrovascular accident—a stroke. Caused by a blood clot or bleeding in the brain, a stroke can occur with sickle-cell anemia, brain tumors, or other conditions. To find out why this had happened to Jennifer, I needed some help. I called the pediatric neurologist at the children's hospital. He agreed that Jennifer should be admitted, and Karen took her that afternoon.
A few days later, I got a call from the genetics specialist at the children's hospital: "Mark, good news. It looks like we have an answer on Jennifer Harada. The MRI scan confirmed a stroke, caused by a blood clot. Combining that with her developmental problems, I checked the homocysteine level—and it was sky high! She has homocysteinuria."
I knew homocysteinuria was a rare genetic disease in which a very high blood level of the amino acid homocysteine—at least 10 times the normal amount—damages the developing brain. Recent research has shown that homocysteine may also be a marker for increased risk of heart attack (perhaps even more important than cholesterol) because it makes the blood clot more easily. With extremely high levels, like Jennifer's, a child can have a stroke.
"So what's the good news?" I asked.
"We have a treatment," he said. "There's a supplement called Betaine that can lower homocysteine levels. I'm going to start Jennifer on it right away. With luck, if we can lower her level, we can prevent further strokes."
Although no treatment could have reversed the damage done to Jennifer's developing brain, her homocysteine level did come down with the Betaine treatment, and she hasn't had another stroke. About six months after the stroke, I saw Jennifer for her fourth-year checkup. I was amazed: She played with toys, smiled, and looked at me in a way she never had before. She was learning sign language to help her communicate and developing an engaging personality. While Jennifer was still developmentally delayed, she no longer appeared autistic. And that was wonderful news.
