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This is the story of a late-treated adult who went off the diet at a young age. In his 30's, he began experiencing psychotic behavior. He was returned to diet with complete reversal of the symptoms.
Our son, Kevin, was born in May 1956, before newborn screening for PKU. He seemed to be developing normally until he was about eight months old. We noticed his disinterest in his surroundings and realized he was missing important developmental markers for his age. When he was 10 months old, we took him to Henry Ford Hospital where he was diagnosed 'severely mentally retarded, cause unknown.' He started having petit mal seizures, and eventually grand mal seizures. We took him to the University of Michigan Hospital where his PKU was finally diagnosed. At the time, the only low phe diet product was an experimental medical powder. We were advised about the diet and using this product, but little was known about how effective the diet would be. As it turned out, the diet made a startling change in our son. Though he remained retarded, he became more alert, his seizures ended at age 24 months, and he began to make progress in many areas. When he was three years old, however, the attending doctors made a decision that the diet would be of no further benefit. The conventional wisdom at the time was that most growth and development of the brain had occurred by that age; nothing was to be gained by continuing the diet. We were very skeptical of this argument. So we began purchasing the diet powder ourselves (which was by then on the market as Lofenalac), and continued the diet on our own.
At age eight, we finally stopped the diet entirely. Kevin seemed to do fine. He learned to ride a two-wheeled bike, swim, dress himself, and to say enough words to express his needs. Except for hyperactivity, which lasted until about age 12, we were for the most part happy to see how well he did. He developed many skills. In his late teens he learned to cross country ski, play the piano by ear, set the table, make his bed, and do a number of little chores around the house. In adulthood, his hyperactivity was minimal. We could take him anywhere, from a fine restaurant to the symphony, and be sure he would behave appropriately. He moved about in our neighborhood independently. He walked six tenths of a mile to the mail box every day and loved to go outside to ride his bike on the road, or to walk to the beach. He learned to turn on the computer, use the word processor and play some word and matching games. He played Nintendo like a pro.
In June 1994 he began to experience digestive problems and indicated pain on swallowing his food. We gave him antacids and urged him to eat more slowly. But his discomfort escalated. We took him to an internist for a barium swallow. It was inconclusive. Eventually his pain became so great that an endoscopy was done. It showed ulceration of the esophagus, a very serious condition than can lead to cancer. He was started on three different drugs.
The nightmare that followed is what we want to share with all parents of adults with PKU who were removed from the diet in childhood. We also want to impress on teens and young adults who are abandoning their diet that they may be on a dangerous track.
Kevin's medication for the treatment of gastrointestinal reflux disease was begun in the summer of 1994. By the end of that summer we noticed that he had stopped riding his bike. On a visit to a restaurant, he seemed hesitant to step out of the car without our arm for assistance. We noted that he was fearful to walk up even slight inclines and his attempt to walk up a few stairs resulted in full body tremors. As summer slipped into fall, he began to resist going outside but would venture out to the porch. We began to think that the problem might be his vision. He has rather severe myopia. A return visit to the eye doctor showed no change in his vision that could account for his strange behavior. In late fall, we awoke one morning to find Kevin standing in the doorway of his bedroom, clutching the doorjamb with both hands. He had intended to walk to the bathroom, but his strange fear had kept him from going from one space to another. He was drenched in sweat and had full body tremors. From that day through the rest of the Fall, he would not move from one room to another without assistance.
We did not know where to turn for help. We blamed the drugs he was taking and began to withdraw them We consulted a clinical psychologist who came to the house to observe. He diagnosed agoraphobia (avoidance behavior caused by irrational fear). He told us this behavior, if not treated, could eventually cause Kevin to become housebound. But there were obvious problems using counseling techniques with a retarded person. And we were reluctant to resort to psychotropic drugs. By this time, Kevin's agoraphobia was so bad that the only way we could get him to leave the house for any reason was to literally drag him, kicking, sweating, trembling, and crying "no, no, afraid." At one point, he had such a bad episode that we could not move him from the chair in which he was seated because of the grip he had on the arms. After hours of coaxing, we finally had to call 911. With great difficulty and over an hour of effort, the ambulance crew got him to the hospital, where he was treated with tranquilizers. We were heartbroken to see the state our son was in.
We were finally referred to a neurologist by our internist. The neurologist listened carefully to the story of our once-active self-confident son, and the terrified young man we were now sadly trying to help. The neurologist told us that one of the drugs our son was on for the gastric reflux problem could be responsible for the avoidance behavior. But he did not think that alone could have caused such a radical change. And since the drug had now been out of his system for more than 90 days, he was inclined to suspect that a very high level of phenylalanine was the real culprit. We were dumbfounded and skeptical. After all, we explained, Kevin, though irreversibly retarded, had been a fine happy boy with many skills and was well behaved. He never before displayed bizarre behavior like this and had been off the diet for over 30 years.
A CAT scan and an EEG showed nothing unusual. A blood test showed that Kevin's phe levels was 37 mg/dl (2220 mol/L). So, we began at once to reduce the high protein foods in his diet. We could not rest until we could see with our own eyes whether high phe levels were responsible. But we knew that we needed professional advice on how to reintroduce the diet safely. By this time, through the Internet, we had found other reports of PKU individuals who had begun to experience this behavior in adulthood (Waisbren 1991). Reports of improvement through diet, and encouragement from Virginia Schuett, made us believe lowering Kevin's phe level could change the behavior. Although they were very skeptical high phe levels caused the agoraphobia, the PKU clinic agreed to help us restart the diet.
Our son has now been on the diet for about seven months. His phe level is in the range of 2-4 mg/dl (120-240 mol/L). He accepted the diet well right from the start. And his fears began subsiding almost immediately. Within weeks of starting the diet, he began walking miles on our beach again. This was the same person who could not even walk from one room to another without holding someone's hand! He is doing all the things that he enjoyed before and is a happy self-confident guy, with no sign of agoraphobia. His ability to verbalize has always been limited, but he even is using more speech to communicate. Our story is not a completely happy one, though. Despite how effective the diet has been, the clinic has decided to deny further formula. The physician in charge is simply "not recommending diet." We believe this is very wrong and plan to appeal the decision.