QOngoing studies continue looking into the causes of autism spectrum disorders. These disorders generally become evident within a child's first three years of life and range from mild to severe developmental and socialization delays. With various degrees of severity, the disorders have a core set of symptoms that include difficulty forming relationships, difficulty understanding or responding to emotional signals from others, difficulty using language creatively and receptively, self-absorption and repetitive behaviors such as staring, hand-flapping and repeating words over and over again.
Causes/etiologyAlthough no exact cause has been discovered for autism spectrum disorders, researchers believe that there is some genetic component due to the fact that autism runs in families. Studies are ongoing to seek linkage between brain abnormalities and autism.
Thimerosal has been a hot topic when searching for the cause of autism. Thimerosal was a commonly used preservative in most vaccinations to prevent bacterial contamination. The scare began when in 1999, the Food and Drug Administration issued a warning that thimerosal-containing vaccinations could potentially cause blood mercury levels that could exceed the Environmental Protection Agency guidelines.
Unfortunately, what is not understood, is that the mercury in thimerosal and ingested mercury from food are two different forms. The mercury in thimerosal is excreted quickly in the stools. Ingested mercury can enter the nervous system and the brain, whereas the size of the mercury particles in thimerosal makes this unlikely.
The incidence of autism continues to rise even though non-thimerosal containing vaccines have been available since 2001. Finally, no child diagnosed with autism has ever displayed the physical symptoms or laboratory confirmation that mercury toxicity was present.
The measles-mumps-rubella (MMR) vaccination has also been studied as a potential cause of autism. The initial study from the United Kingdom that sparked this argument described only nine children who, after receiving the MMR vaccination, exhibited abdominal symptoms and eventually were diagnosed with autism. The researchers in this case have since retracted their findings. Further extensive studies have been performed which are unable to prove a link between the MMR vaccine and autism.
A child's vaccinations occur in the first two years of life, corresponding to the time more symptoms of autism become evident. The benefits of vaccinations are obvious. Diseases like polio and diphtheria, which in the past had caused significant illness, disability and death, have been eradicated through the almost universal administration of vaccines.
In its latest review, the Immunization Safety Review Committee of the Institute of Medicine concluded that there is no evidence that thimerosal or administration of the MMR vaccination causes autism.
TreatmentIt is important that treatment of autism spectrum disorders begin as early as possible in order to increase skill development. The goal of treatment is to improve communication skills, socialization and problem behaviors. Methods including behavioral training, speech and occupational therapy, parent education, and school support. Individual needs should be addressed by the school and an aide provided if necessary. Children with an autism spectrum disorder need a specialized educational program with an even more highly structured environment.
Approximately 50 percent of children with autism have below normal intelligence. They demonstrate uneven skill development, i.e. problems in certain areas like socialization and communication. However, they may also have unusually developed skills in other areas like math, drawing, creating music or memorizing facts. They may test average to above average in nonverbal intelligence testing due to these skills.
Previously hypothesized treatments using heavy metal chelation and the hormone secretin have not been proven to change or improve the symptoms of autism.
Medical conditions such as depression, anxiety, seizures and behavioral disorders should be addressed and treated by a primary care physician.
In summary, autism is defined as a spectrum disorder with a core set of symptoms. The diagnosis is based mainly on medical, developmental and behavioral history. Research is ongoing to find a cause as to why autism develops. Most importantly, individualized behavioral modification techniques and communication between the parents, school and physician should be instituted as early as possible in order to maximize a child's potential.
Kristie L. Kaufman, MD, is a board-certified physician, specializing in pediatrics health care. She practices at Centre Medical and Surgical Associates and is a member of the medical staff at Mount Nittany Medical Center.