What to Expect the Toddler Years (258 page)

How common is it?
About 1 child in 800 is affected.

Who is susceptible?
Children of all ethnic groups and socioeconomic levels. But babies of parents who have already produced a child with Down syndrome, babies of a parent with a chromosome rearrangement (see below), and babies of mothers (and possibly fathers) over thirty-five are at a higher risk.

What causes it?
In 95% of cases, an extra chromosome contributed by one of the parents, giving the baby 47 chromosomes instead of 46. The extra chromo-some is a number 21 chromosome; since the Down syndrome individual has three number 21 chromosomes instead of the usual two, this arrangement is called trisomy 21.

Related problems.
About half of the children with Down syndrome have a congenital heart defect and about 5% have a gastrointestinal abnormality. Some have a weak immune system (making them more susceptible to everything from respiratory illnesses to leukemia and other cancers) and/or hearing and vision deficits, thyroid dysfunction, and a tendency toward premature aging. Though children with Down syndrome are inherently at risk of obesity, positive familial and other environmental factors, including dietary control and physical activity, can reduce the risk.

Treatment/management.
If prenatal diagnosis was not made, chromosome studies need to be done after birth to confirm the diagnosis of Down syndrome and determine the type of chromosome abnormality responsible. Early specialized education programs can dramatically improve the IQs of Down syndrome children, bringing some into the “normal” range. Good medical care can often reduce related problems. Surgery, for example, may be able to correct heart and digestive defects. In some countries, surgery is performed to normalize appearance, but the benefits are debatable.

Prognosis.
Varies depending on severity of condition. Most children with Down syndrome have greater capabilities than was previously believed, and intervention begun as soon as the condition is diagnosed can make the best of these abilities, leaving fewer than 10% severely retarded. Many children with Down syndrome can be mainstreamed for a while in school; most later find places in sheltered homes and workshops; a few are able to live and work independently, and some marry. The average life span, once the hurdles of the first two to ten years are surmounted, is fifty-five, more than twice what it was in the past.

What is it?
A chronic disorder of the brain that causes recurrent seizures. A seizure is a sudden, temporary, involuntary alteration in physical movement or consciousness. The severity and type of seizure as well as how much and what part of the body is affected vary depending on the portion of the brain involved. Though seizures used to be grouped into “grand mal” and “petit mal” categories, the new classifications are more specific. Seizures can range from involuntary convulsions of the entire body to a sudden and brief lapse of awareness of the environment. An epileptic seizure is a temporary malfunction and does not mean the brain is deteriorating in any way.

How common is it?
About 1% of the American population has epilepsy, including about 300,000 children under the age of 14. It can affect children at different times in their lives and in different ways and can even be outgrown. Not all seizures are epileptic. Febrile seizures, for example, are not—and half of all children who have one febrile convulsion never have another.

Who is susceptible?
Possibly someone with a genetic predisposition to epilepsy. Also, an individual who has sustained severe trauma of some sort to the brain (sometimes one that was undetected).

What causes it?
Abnormal electrical discharges in the brain, due to an insult to the brain from any of a wide range of causes, including: head injury, brain infection, a metabolic disorder, damage during fetal development, severe hypoglycemia (low blood sugar), and (rarely) a tumor. No cause can be determined in about half of those with epilepsy.

Related problems.
Epileptics may face a slightly increased risk of accidental injury.

Treatment/management.
The first step is diagnosis; report a first seizure to your child’s doctor, including such details as what preceded it, what your child looked like, and how long it lasted (it’s often difficult for an observer to be sure a child really is having a seizure, especially when the seizure is very brief). Diagnosis, evaluation, and classification of seizures is best made by a specialist; but the day-to-day medical care of a child with epilepsy can usually be handled by the pediatrician. Medication or a combination of medications, carefully monitored, can often control or reduce the incidence of seizures. When medication doesn’t work, surgery may be considered. Rarely, a special diet—usually high in fat, moderate in protein, and low in carbohydrates—is recommended.

Since children with epilepsy are at a potentially higher risk of drowning (if they suffer a seizure in a bathtub or a pool, for example), they should never be left unattended near water, no matter what their age or how well they swim. They are also
slightly
more likely to be injured at play, but this is not a reason to overprotect them and keep them from doing what comes naturally (playing running games, climbing on the jungle gym, riding trikes, and so on). Any restrictions on activities should be placed only in consultation with the doctor, taking into account the risk that such restrictions will hinder normal development.

For handling a febrile seizure see page 584; epileptic and other seizures are usually handled in a similar way (see page 667). Emergency help should be sought for a seizure that lasts more than 15 minutes.

Prognosis.
Seizures can be completely controlled without serious medication side effects in 8 in 10 children. After two seizure-free years, a child is generally no longer considered epileptic and medication may be stopped. With appropriate management and support, the great majority of children who continue to have epilepsy can become competent and functioning adults.

What is it?
An X-linked chromosomal disorder. Typically, boys with fragile X syndrome have delayed speech and language development, prominent foreheads and jaws, low-set ears, long and narrow faces, large testicles, and other physical abnormalities. Some have only mild learning disabilities, and it’s estimated that 1 in 5 boys with the fragile X chromosome has no symptoms at all. Most female carriers are also symptom free, though 1 in 3 is mildly to moderately mentally retarded or has a learning disability.

How common is it?
An estimated 1 in 3,600 boys and 1 in 6,000 girls are affected, which makes fragile X syndrome one of the major causes of mental retardation in the U.S. Most cases of fragile X, however, are not diagnosed as such.

Who is susceptible?
Because the disorder is linked to the X chromosome, males are much more likely to exhibit the full-blown syndrome. (Males have only one X chromosome; unlike women, they have no second X chromosome with a normal gene to counteract the fragile X with the defective gene.)

What causes it?
A defect in a gene on a fragile, or thinned-out, section of the X chromosome.

Related problems.
Problems of motor coordination and balance after age ten. About 14% are also autistic and display many of the symptoms of autism (see page 712).

Treatment/management.
At present, early intervention to deal with mental retardation is the prime treatment (see page 726). When the specific gene responsible has been identified, it is hoped that it will be possible to correct the defect through biochemical manipulation.

What is it?
There are several types of hearing loss in children:
Conductive hearing loss.
In this type of hearing loss, sound is not conducted efficiently through the ear canal; the loudness of a sound is reduced.
Sensorineural hearing loss.
In this type of hearing loss, there is damage to the inner ear or to the nerve pathways from the inner ear to the brain. Loudness of sound is reduced, and so is the child’s understanding of spoken language.
Combined hearing loss.
Combines both of the above.
Central (or retrocochlear) hearing loss.
Child hears sounds but is not able to decipher words.

There are many degrees of hearing impairment or hearing loss, and not all children with hearing loss are “deaf.” The child who is deaf has a profound hearing loss and cannot understand speech through hearing alone, even with the use of a hearing aid.

Toddlers who are hearing-impaired use their hands to “babble” and to talk; the movements, though they are not real sign language, are organized and very much like the jargon of a hearing toddler.

For signs of hearing impairment, see page 488. If you suspect that your toddler doesn’t hear well, speak to his or her doctor.

How common is it?
According to the American Academy of Pediatrics, 2 to 3 out of 1000 babies are born with some hearing loss each year.

Who is susceptible?
See page 488.

What causes it?
Conductive hearing loss.
Malformation of the outer or middle ear. Also, colds, allergies, otitis media (middle-ear infections), but illness-related hearing loss is usually temporary.
Sensorineural hearing loss.
Malfunction of inner ear or damage to the auditory nerve; such damage becomes more common with age. When the nerve is damaged, hearing loss is usually permanent. The causes of sensorineural hearing loss may be prenatal, perinatal, or postnatal, acquired or genetic; the incidence has been reduced by the decrease in congenital rubella and Hib meningitis in infants and by better treatment of meningitis when it occurs.
Central hearing loss.
Changes in the auditory centers of the brain due to injury, disease, tumor, heredity, or unknown causes.

Related problems.
Poor language development, poor learning, lack of self-esteem.

Treatment/management.
It is important to diagnose a hearing loss early and to determine the level of impairment, which can range from mild to profound. The first step is testing by an audiologist. If the child does not pass the instructions the first time around, a retest may be ordered (sometimes a child misunderstands the first test or has a cold or other infection that temporarily hampers hearing) or the child may be referred to a pediatric otolaryngologist for further testing and treatment.

Treatment of hearing loss, beginning as soon as a diagnosis is made, is very important, not only to maximize a child’s future hearing and language development, but to protect self-esteem. Treatment may be provided by both an otolaryngologist and an audiologist, and may include:

Medication.

Surgery. Cochlear implants can often restore limited hearing (often to the point where conversation can be understood) and improve the ability of totally deaf children to learn spoken language. However, these implants have been opposed by some in the deaf community who see implants as a negative approach to dealing with deafness, which they see as a way of life, and not a disability. For a cochlear implant, a child must be at least two years old, have profound bilateral sensorineural hearing loss, and have received limited or no benefit from conventional hearing devices.