Children diagnosed with sickle cell disease once were expected to live barely into their 20s, but medical breakthroughs have more than doubled that lifespan, and now researchers are focused on a new dilemma -- decades of living with the condition may lead to poor brain function.
In a study being published Wednesday in the Journal of the American Medical Association, researchers from Oakland Children's Hospital found that adults with sickle cell disease had lower IQ scores than patients in a control group. The study didn't look into reasons why the scores may be lower, although the authors suggested that anemia caused by sickle cell disease may be a factor.
The good news is that the cognitive problems seem to be reversible -- researchers didn't find any correlating brain damage to explain the IQ results, and doctors already are conducting follow-up studies to determine if treatment with blood transfusions can help patients with memory or cognitive problems.
"As sickle cell has changed from a pediatric disease and life spans have increased, quality of life is the name of the game," said Dr. Elliott Vichinsky, director of hematology and oncology at Oakland Children's Hospital and lead author of the study. "My biggest concern when I meet with families now is not survival of the child, but the impact of chronic organ dysfunction and age."
Sickle cell disease is an inherited disorder in which red blood cells aren't round, but take on a distinctive "sickle" shape. The shape makes it difficult for the cells to move through blood vessels and can lead to anemia. The disease can cause severe pain, stroke and organ failure. Children are usually diagnosed with sickle cell disease at birth.
Medical advances over the past decade have made treatment more successful, although most people with sickle cell disease still die by age 50. But the longer lifespan means doctors are discovering the long-term effects of living with sickle cell disease.
It has long been known that people with sickle cell disease are at higher risk for strokes, which can in turn cause brain damage and affect cognitive function. But Vichinsky said he wondered about some of his own patients who had no obvious signs of brain damage
-- no history of strokes and normal MRIs -- but seemed to have trouble making appointments or following medical instructions.
The Children's Hospital study is one of the first to look at brain function in adults with the disease.
The study looked at 141 sickle cell patients and 44 healthy subjects, all between ages 19 and 55. None of the participants were taking medications or had serious underlying health conditions -- like diabetes, depression or damage to the lungs or kidneys -- that might affect their brain function.
They were given an MRI and an IQ test, which included tests of their memory, attention level, language skills and ability to follow instructions. The normal IQ range would be a score of 85 to 115.
Most of the sickle cell patients fell within that range, but were lower overall than the healthy participants -- they had a mean score of 87 compared to 95 for the health subjects. About a third of the sickle cell patients were below the normal IQ range.
Vichinsky doesn't yet no what's causing the IQ results, but he suspects chronic oxygen deprivation, due to sluggish blood flow from the misshapen red blood cells, which may affect brain function.
Their MRIs don't show damage that would cause the cognitive dysfunction, which may mean that the problems are treatable, Vichinsky said. Some patients could be treated with medicine, while others might benefit from cognitive training, like learning how to use notebooks to jog their memory, or keeping appointment calendars and checklists.
"As you get past 55 or 60, you start seeing a progressive decline in cognitive function. What I saw in the patients was the change you would see in normal senior citizens over time," Vichinsky said. "But I do think there are very concrete things one can do. This study should empower patients to get better cognitive testing and get treatment."
Ashley Holley, 26, was skeptical of Vichinsky's research when she first heard about it. She has sickle cell disease, and is well aware of the decades of discrimination leveled at people with her condition -- most notably, men and women who were turned away from jobs in the 1970s simply because they carried the gene that causes sickle cell disease.
Holley works with Vichinsky as a study coordinator, and while she admits with a laugh that she could be a little better organized, she said she's never felt at a disadvantage because of her disease. The last thing patients need is another stigma associated with sickle cell, she said.
"I don't want this study to come across as we can't hold jobs, because we can and we do. We're able to lead healthy, productive lives, and we can work in every field imaginable," Holley said.
But if it's true that patients with sickle cell disease do suffer some cognitive problems, it's better to address the problem head-on than pretend it doesn't exist, she said.
"If we don't know there's a problem, we can't find a way to treat it or manage whatever deficit there is," she said. "This is how we make advances in research. "If discrimination comes from results such as this, I'm willing to take on that fight."
source: stltoday
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