WASHINGTON — Recognizing and acting on areas of medical vulnerability can prevent secondary developmental disability in children with Down syndrome.
“For most parents, Down syndrome already implies that the child will not develop as they had expected,” William I. Cohen, M.D., said at the annual meeting of the American Academy of Pediatrics. “But it's possible to optimize their learning by early detection of issues that have developmental consequences.”
Problems with hearing, vision, sleep, and hypothyroidism are most likely to affect learning, said Dr. Cohen, director of the Down Syndrome Center of Western Pennsylvania, Pittsburgh.
The midfacial hypoplasia typically seen in Down syndrome is the root of many ear, nose, and throat problems, he said. “All the midfacial anatomy is smaller, and this contributes to the numerous ENT infections we see in these kids.”
Purulent nasopharyngitis and sinusitis are common, as are repeated otitis media infections. These problems can result in hearing loss if not aggressively managed, he said. “Hearing loss can be due to fluid in the middle ear getting trapped because of the really small eustachian tubes, which may also have an abnormal orientation.”
Sometimes the ear canal is so small that it's not possible to visualize the tympanic membrane. This warrants an immediate referral to an otolaryngologist.
“These children need aggressive medical management. If this fails, they may need ventilating tubes. It is common for children with DS to need tubes, and some require multiple sets. The risk of hearing loss is really increased because of the anatomy,” he said.
All Down syndrome children should have a behavioral hearing screen every 6 months until they are 3 years old, and annually thereafter.
A smaller oropharynx, with normal-sized adenoidal and tonsillar tissues, makes snoring and sleep apnea a problem as well; a tonsillectomy and adenoidectomy might be indicated. Sleep disturbances probably also arise from a decrease in REM sleep, which is common in children with Down syndrome.
The trachea and upper airway also are narrower in these children, predisposing them to croup. “Much of this is misdiagnosed, though, and is actually laryngeal inflammation caused by gastroesophageal reflux disease,” he said.
Down syndrome-related ocular problems also can impair learning, Dr. Cohen said. “All of these children could be referred for an ophthalmologic evaluation by the time they are 6 months old.”
The dense congenital cataracts sometimes seen in Down syndrome infants are obvious at birth, but other problems can be present as well. Strabismus is frequent, and refractive errors occur in up to 50% of these children.
Congenital hypothyroidism is about 27 times more common among Down syndrome children, though it is still rare. In general, 20% of children with DS may develop hypothyroidism. The etiology is usually autoimmune, most often Hashimoto's disease. Newborn screening will pick up congenital hypothyroidism, but children should have repeat measures of thyroid-stimulating hormone and free T4 at their 6-month and 1-year checkups. The measures should be performed annually thereafter, he said.
Dr. Cohen also recommends using both normal and Down syndrome-specific growth charts for these children. “The Down syndrome charts will pick up growth problems, but since they're adjusted for weight and height, they might not pick up weight problems like a regular growth chart will.”