Published onTrisomy 21 Update
In the 1960s, the life expectancy of a child with Down syndrome (DS) was approximately 30 years. Today, expectations for longevity have dramatically changed, with most individuals living healthy lives into their 60s and 70s.
Much of this improvement is attributed to advances in cardiac surgery and post-surgical care. But, overall, there is increased awareness of the medical conditions that are more common to this special population of children.
In 1994, a committee of the American Academy of Pediatrics (AAP) issued guidelines, entitled Health Supervision for Children with Down Syndrome, for the first time. The intention was to assist pediatricians in identifying, understanding and addressing relevant medical issues. Since then, the document has been revised periodically, most recently in 2011, offering up-to-date information and standardizing care on the basis of physician experience and dedicated research.
Interestingly, the initial guidelines fit in a concise five pages; the current set has nearly tripled to more than 14 pages. Looking specifically at the changes in recommendations over time allows us to trace the evolution of our knowledge, but also highlights the value of the document itself.
In 1994, pediatricians were advised that a woman given a prenatal diagnosis of Down syndrome might be referred to a pediatrician for discussion of issues including manifestations of the syndrome, available treatments, burdens of the interventions (both medical and financial), prognosis and recurrence risk.
At that time, only women over 35 years of age were targeted for screening, missing nearly 50 percent of pregnancies affected by trisomy 21. Today, universal screening offers the option of noninvasive diagnostic testing to all pregnant women, regardless of age or other risk factors.
Improved blood tests and ultrasound findings are very sensitive, allowing combined first- and second-trimester screening to identify approximately 95 percent of cases. This gives most families advance opportunity for adjustment, education and development of collaborative relationships with physicians and community support networks.
While the obstetrician may explain the results of prenatal screening, choosing a pediatrician during the pregnancy establishes a long-term partnership that will thereafter provide information, guidance and a liaison to other involved specialists.
From infancy forward, growth is an important indicator of child health and deserves special consideration for children with DS, who may exhibit feeding difficulties in infancy or obesity risk in later childhood. While it was previously recommended that growth progress should be tracked using Down syndrome-specific growth charts, the AAP now suggests that these charts are outdated.
Because the data used to devise the charts was collected in the 1960s and ’70s, they may no longer reflect current health standards and should be abandoned for use of standard growth charts issued by the World Health Organization. Unfortunately, comparing growth trends for children with DS to the general population discounts the unique patterns that may be expected due to trisomy 21. Assessing growth with respect to expectations for their cohort could assist in identifying conditions that might otherwise remain silent, such as hypothyroidism or celiac disease.
The Down Syndrome Growing Up Study, currently under way at CHOP, is striving to clarify the nuances of these growth patterns. Perhaps, by the next revision of the AAP guidelines, new DS growth charts will be available.
At times, a change in recommendations has been preceded by controversy, raising confusion for both parents and healthcare providers. Historically, pediatricians were advised to obtain an X-ray of the cervical spine (vertebrae of the neck) for every child between 3 to 5 years. Both the 1994 and 2001 AAP guidelines recognized that the value of the X-ray was questionable, but it wasn’t until the 2011 revision that the recommendation was reversed.
We know that children with DS have increased risk for laxity of ligaments, including the atlanto-axial joint in the upper neck. While this raises concern for instability of the joint and compression of the spinal cord, an abnormal X-ray cannot predict which children will develop neurologic symptoms, nor can a normal X-ray reassure that no later consequences will develop. In fact, many children have an abnormal appearing X-ray (10 to 30 percent), but only 1 to 2 percent will ever develop symptoms as a result.
Routine X-rays of the cervical spine in a child without symptoms are no longer recommended, but vigilance regarding symptoms that suggest spinal cord impingement is paramount; these symptoms should be reviewed with the pediatrician at every well-child visit.
Protection of the spinal cord through avoidance of high-risk sports and neutral neck positioning, including during surgery and dental procedures, should be implemented for all children with Down syndrome, regardless of whether an X-ray has been performed.
The importance of screening for obstructive sleep apnea has also gained focus over time. With no mention of the risk in the 1994 guidelines and a brief mention of possible symptoms in 2001, it is now widely understood that the high prevalence and significant consequences of obstructive sleep apnea in children with DS warrant more specific evaluation.
While it is important for parents to watch for symptoms and report concerns, several studies have demonstrated a poor correlation between parent report and sleep study results, indicating a need for objective assessment. As such, symptom review should be started in early infancy, giving parents a better sense of how to monitor for suspicious signs. But even children presumed to be asymptomatic should be referred to a sleep center for a polysomnogram (sleep study) by 4 years old.
Another addition to the most current guidelines, not considered in past versions, is the increased risk of celiac disease. Though laboratory studies are not advised, pediatricians are encouraged to maintain a low threshold to test for this autoimmune response to dietary gluten. Because the spectrum of symptoms in celiac disease is broad, encompassing both gastrointestinal and behavioral effects, blood antibody levels provide a more accurate indicator of whether change in diet would offer benefit.
Just as the personality of every child with Down syndrome is unique, the constellation of health issues for each child will vary as well. But the known risks for particular conditions allow us to seek and minimize complications before they occur. It is gratifying to trace how far we’ve come in our ability to effectively care for children with DS, even in recent history. But we are also reminded that expert opinion continually changes with the acquisition of better information.
Familiarity with the most current AAP guidelines empowers families to engage in a productive dialogue with their healthcare providers and advocate for the highest quality of care for their children. A more extensive review of the AAP guidelines, Health Supervision for Children with Down Syndrome, can be found on the website for the National Down Syndrome Society at http://www.ndss.org/Resources/Health-Care/Health-Care-Guidelines/.