Clinical Aspects of Down Syndrome from Infancy to Adulthood
Siegfried M. Pueschel
In past decades, most individuals with Down Syndrome were usually not afforded adequate medical care. Many children with Down Syndrome were institutionalized and they were often deprived of all but the most elementary medical services. Fortunately, there have been major improvements in the health care provision during the past 20 years.
Professionals who are providing services to persons with Down Syndrome need to be aware of those clinical conditions that are more often observed in this population. Certain congenital anomalies (congenital cataracts, anomalies of the gastrointestinal tract, and congenital heart disease) often require immediate attention, as some of them may be life threatening. During the subsequent childhood years a number of clinical conditions and disorders such as infectious diseases, increased nutritional intake, periodontitis, seizure disorders, sleep apnea, visual impairment, audiologic deficits, thyroid dysfunction, and skeletal problems usually occur at a higher prevalence. During adolescense specific aspects of maturation and certain health issues (skin infections, thyroid disorders, increased weight gain, and others) as well as mental health concerns need to be taken into consideration. Similar concerns may also be observed during adulthood which in addition is often marked by accelerated aging and the threat of Alzheimer disease in some persons with Down Syndrome.
Special attention needs to be paid to these disorders and conditions during the lifetime of a person with Down Syndrome. Appropriate medical care should be provided to and no form of treatment should be withheld from a person with Down Syndrome that would be given unhesitatingly to an individual without this chromosome disorder.
KEYWORDS: natural history, childhood, adolescence
When John Langdon Haydon Down published his classic paper in 1866 describing the phenotype of persons with the syndrome which today bears his name, he focused on only 2 clinical manifestations indicating that "the coordinating faculty is abnormal" and "the circulation is feeble." However, since then many clinical-pathological findings have been reported. In particular during the past decades, we have become aware of numerous medical concerns in persons with Down Syndrome.
Within the framework of this paper it is not possible to cover all clinical disorders observed in persons with Down Syndrome in an encyclopedic fashion. Only the most important clinical concerns can be discussed. Although some of the medical conditions may occur at any time during the life of an individual with Down Syndrome, certain clinical aspects are described in a life cycle approach, i.e., specific congenital anomalies should be identified neonatally, the detection of visual and hearing impairments need to be pursued primarily in early childhood, sexual maturation is a topic of adolescence, and the accelerated aging process is noted during the adult years.
Clinical Aspects in the Neonatal Period
Certain congenital anomalies of infants with Down Syndrome require immediate attention. Some of them may be life-threatening and need to be corrected at once: others may become apparent during subsequent days and weeks.
Congenital Anomalies of the Gastrointestinal Tract
Congenital Heart Disease
Clinical Aspects in Childhood
Some individuals with Down Syndrome have immunologic deficiencies including T cell and B cell dysfunctions which may render them more susceptible to infections (Levin et al., 1975; Hann et al., 1979). As in other children, infectious diseases should be diagnosed and treated promptly.
On the other hand, increased weight gain often becomes apparent in many individuals with Down Syndrome. Therefore, it is important to inform parents concerning appropriate dietary practices from early childhood on in order to avoid excessive weight gain. Proper intake of a balanced diet, avoidance of high caloric food items, and regular physical exercises are important for all children including those with Down Syndrome.
Thus, it is important that persons with Down Syndrome are examined regularly by a dentist, that they practice appropriate dental hygiene, receive fluoride treatments, follow good dietary habits, and have restorative care, if needed, which should prevent dental caries and periodontal disease.
It is important to recognize seizure disorders in youngsters with Down Syndrome and to initiate prompt treatment with anticonvulsant medications.
Because children with Down Syndrome have such a high frequency of eye disorders, they should be examined regularly by a competent pediatric ophthalmologist. Normal visual acuity is important for any child. However, if the child is mentally retarded, as most youngsters with Down Syndrome are, an additional handicap of sensory impairment may further limit the child's overall functioning and may prevent the child from participating in significant learning processes.
A hearing impairment in young children with Down Syndrome may affect their psychological development. Therefore, proper assessment of the child's hearing and prompt treatment if a hearing loss is uncovered are of paramount importance. It has been well documented that even a mild conductive hearing deficit may lead to a reduced rate of language development and secondary interpersonal problems.
It thyroid dysfunction is not recognized early, it may further compromise the children's central nervous system function. Because of the clinical symptoms of hypothyroidism are sometimes interpreted as being part of the "Down Syndrome Gestalt," thyroid function studies including T4, TSH, and others, if indicated, should be carried out at regular intervals. It a person with Down Syndrome is found to be hypothyroid, prompt thyroid hormone treatment should be forth coming. Optimal thyroid function then will allow normal learning processes to take place.
Atlantoaxial and Atlantooccipital Instability
It is usually recommended that individuals with atlantoaxial instability not engage in certain sport activities that potentially could injure their neck. If neurologic symptoms become apparent, surgical intervention is indicated.
Both atlantoaxial and atlantooccipital instability in individuals with Down Syndrome should be identified as early as possible because of its relatively high prevalence and its potential for remediation. We recommend that a radiograph of the cervical spine be obtained in all persons with Down Syndrome at age 21/2 or older. Since most individuals with Down Syndrome may have difficulties verbalizing specific complaints relating to neck discomfort and neuromotor difficulties, a neurologic examination and radiographic studies are often indicated. Sometimes, their motor dysfunction and broad-based gait may conceal significant neurologic concerns. Therefore, it is important to diagnose children with atlantoaxial and atlantooccipital instability, since a delay in recognizing these conditions may result in irreversible spinal cord damage.
Clinical Aspects in Adolescence
In recent years novel programs that focus on the transition from adolescence to adulthood have been developed with the goal to assist the young person with Down Syndrome to prepare for the world of work.
We have studied adolescent development in boys with Down Syndrome (Pueschel et al., 1985) and found that the patients' secondary sex characteristics are quite similar to those of normal youngsters. There was no significant difference between the size of the genitalia of adolescents with Down Syndrome and that of normal control boys. Concerning hormone measurements, serum follicle stimulating hormone, lutinizing hormone, and testosterone levels increased with advancing age up to 18 years in our study population similar to those hormonal changes observed in normal adolescents.
With regard to the sexual maturation of girls with Down Syndrome, our studies showed that the average onset of menstruation was 12.5 years, whereas the average menarche of their nonhandicapped sisters was 12.1 yours. Most girls and women with Down Syndrome have regular menstrual cycles. The length of the menstrual cycle varies between 22 and 33 days with a mean of 27 days. Their average menstrual flow lasts approximately 4 days. Two-thirds of the adolescent girls with Down Syndrome have concomitant symptoms such as cramps, headaches, lethargy, and abdominal bloating.
Ovulatory patterns of women with Down Syndrome were studied by Tricomi et al. (1964). These investigators found that 39% of the women showed a definite pattern of ovulation, 15% probably ovulated, another 15% possibly ovulated, and 31 % had no evidence of ovulation.
Although both males and females with Down Syndrome displayed fairly normal sequential development of primary and secondary sex characteristics and their pituitary-gonadal axis appears to be intact, there are still many unanswered questions concerning the adolescents' sexual functions, libido, and fertility. Since most individuals with Down Syndrome now live in the community with all its risks, opportunities, and freedoms, it is paramount that further studies concerning adolescent and sexual development be pursued.
Health Issues in Adolescence
Increased Weight Gain
Parents of children with Down Syndrome should have nutritional counseling starting shortly after the birth of their child in order to establish appropriate eating habits that will prevent obesity in their child.
Clinical Aspects in Adulthood
Many of the topics that have been discussed before also pertain to the mature person with Down Syndrome. Appropriate nutrition, regular exercise, prevention of infectious diseases, testing for thyroid disorders, identification of skeletal abnormalities, routine dental examinations, and others are equally important in this age group. However, 5 conditions need particular mention:
Mitral Valve Prolapse
Although neuropathologic specimens from autopsies indicate that persons with Down Syndrome have histologic evidence of Alzheimer disease, one cannot state categorically that Alzheimer disease will be present in all persons with Down Syndrome beyond the age of 30 or 40. Reports from institutions for persons with mental retardation as well as our own observations indicate that many adults with Down Syndrome are as "normal" as other handicapped people and hardly ever exhibit personality changes or psychological problems as observed in Alzheimer disease. Ellis et al. (1974) mentioned that the detection of dementia may be difficult. In spite of these difficulties, observations of early signs of Alzheimer disease have been reported in 15-25% of elderly persons with Down Syndrome.
As detailed above, there are numerous clinical concerns in persons with Down Syndrome which should be taken into consideration in the course of their medical care. If provided with optimal medical services, fostering their well-being in all areas of human functioning, the quality of life of individuals with Down Syndrome will be enhanced and their contribution to society will be substantial.
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