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Medical management of the adult patient with Down syndromeLonger life expectancy and relative independence among people with Down syndrome mean a unique ambulatory population for the family practice setting. How can you best address the medical needs of these patients?Ray Galley, PA-C, MPHThe author is a family practice physician assistant at La Familia Medical Center, Santa Fe, NM. He has indicated no relationships to disclose relating to the content of this article.
Down syndrome (DS) is the single most frequently identified cause of mental retardation in North America. Extra chromosome (trisomy) 21 is present in 95% of DS patients with phenotypic expression (see Figure 1). This genetic condition occurs in 1 in 800 to 1 in 1,000 live births in the United States, a total of 3,000 to 5,000 newborns annually.1 Life expectancy for people with DS has increased in recent decades; more than half of them live into their 50s, with a considerable number surviving into their late 60s (13.5%) and beyond.1 Many people with DS function in the community with minimal supervision. Their longer life expectancy and relative independence present a unique ambulatory population for the family practice setting. This article reviews common health problems in people with DS. An overview of the patient with DSThe person with DS is usually shorter than average, slower, and less active, with a hoarser voice, rougher skin, and a tendency to gain weight.2 Eighty percent of young adults with DS report that they are in good general health.3 Adults show a wide range of intellectual ability, with IQ points corresponding to an age between 1 and 9 years. Their self-help skills correlate well with IQ, and they demonstrate varying ability with feeding, toileting, household tasks, and personal hygiene. In order to promote a trusting relationship, the clinician should take care to address the DS patient directly; this approach permits assessment of the patient’s language skills and evaluation of the living situation, and it allows the PA to gain the confidence of the patient, family, or caregiver.4
Cardiac diseaseOnce the major cause of mortality among newborns who have DS, congenital heart disease is now frequently reparable. Adults with DS who have no history of cardiac disease and no symptoms of cardiac problems may eventually develop valvular defects. Mitral valve prolapse may be present in more than half of all adults with DS, while up to 17% may have tricuspid valve prolapse.6 Mitral valve prolapse is associated with an increased risk of progressive mitral regurgitation. Complications such as endocarditis, rhythm disturbances, and cerebral embolism may result from chronic mitral valve disease. Careful auscultation is usually sufficient to screen for valvular regurgitation, which can then be confirmed with echocardiography. The clinician should implement prophylaxis for bacterial endocarditis in patients with valvular disease and continue it in those who have undergone surgical repair as recommended by the American Heart Association. The head and neckMore than half of adults with DS suffer from some form of conductive or sensorineural hearing loss.7,8 The patient with unrecognized hearing loss may appear stubborn or difficult when interacting with people. Communication skills that are poor to begin with may decrease with auditory loss and may limit the patient’s ability to express a hearing problem. Auditory testing is recommended every 2 years to monitor for hearing changes and to minimize the speech problems that may result. Performing pure tone audiometry in the office setting may be possible with a concentrating, cooperative patient. Otherwise, sedation or general anesthesia can be used with brain stem auditory evoked response to obtain a reliable objective diagnosis of hearing loss.9 Obstructive sleep apnea may occur in up to 50% of the DS population.10 Although commonly associated with obesity, underdeveloped facial features combined with smaller airways are also contributing factors to this condition.11 Snoring, daytime somnolence, and apneic episodes are signs of obstructive sleep apnea. The condition may manifest with behavioral changes such as irritability, depression, or paranoia. The diagnosis can be confirmed with sleep studies, although an otolaryngolic referral is necessary. Some patients may tolerate treatment with continuous positive airway pressure devices. Left untreated, obstructive sleep apnea may lead to pulmonary hypertension and cor pulmonale. Health Care Guidelines for Individuals with Down Syndrome recommends an ophthalmologic evaluation every 2 years.5 Keratoconus (conical protrusion of the cornea), cataracts, refractive error, strabismus, and nystagmus are common findings.12 Immunologic changesPersons with DS may have deficits in acquired immunity.13 Those patients with recurrent serious systemic and respiratory tract infections may be deficient in IgG subsets 2 and 4. Patients who experience serious recurrent bacterial infections and deficient IgG4 may need IV gamma globulin therapy.5 Deficits in cellular immunity have the greatest clinical impact on gingivitis and periodontal disease;5 tooth loss, orthodontic problems, and bruxism are thus common conditions. Patients with DS need biannual dental examinations, and the primary care provider should encourage oral hygiene to avoid intermittent bacteremia that could lead to bacterial endocarditis. Thyroid dysfunctionHypothyroidism occurs in 10% to 40% of people with DS.4 The highest incidence of thyroid disease occurs between ages 30 and 50 years, with relatively equal gender distribution.2 Thyrotropin levels can fluctuate in DS patients, while antithyroid antibodies may subsequently disappear.14,15 Occult hypothyroidism may be misdiagnosed as dementia or contribute to a demented state. Because of the increased prevalence of hypothyroidism at all ages, the clinical similarity to trisomy 21, and fluctuating thyrotropin levels, all DS patients should have annual blood tests to measure thyrotropin and thyroxine (T4) levels.5 Treatment of subclinical hypothyroidism (an elevated thyrotropin who require general anesthesia, level with a normal T4 level) is controversial. Because a mildly elevated thyrotropin level in a patient with DS may not indicate hypothyroidism, many authorities recommend monitoring every 6 months for low T4 levels instead of providing hormone replacement. Hyperthyroidism has a much lower prevalence among DS patients, yet occurs more frequently in them than in the general population. Thyroid disease is associated with a three-fold increased risk for hepatitis B carrier state in patients with DS.15,16 The relationship between thyroid abnormalities and hepatitis B surface antigen may result from cellular immune abnormalities.12,16 Although hepatitis B is generally considered a disease of blood transmission, it is actually secreted in all body fluids. Hepatitis B immunization is currently recommended only for people living in residential facilities. Ligamentous laxityPatients with DS are known to have ligament laxity that may result in hyperflexibility of certain joints,17 leading to lower extremity disorders such as pes planus (flatfoot) and patellar instability. Pes planus can be identified by the loss of the longitudinal arch of the foot and a neutral to pronated heel. Treatments include arch supports, special shoes, or surgical stabilization. Flat feet may contribute to patellar instability. Another factor in knee malfunction in DS patients is relative laxity of restraining tissues that align the patella in the intercondylar groove. Suspect patellar instability when a patient complains of knee pain with flexion or instability when walking or descending stairs. Measurement of the Q angle—the angle formed by drawing an imaginary line from the center of the patella to the anterior superior iliac spine and another to the center of the tibial tubercle—may provide useful information in the diagnosis of patellar problems.18 An angle less than 15 degrees is considered normal. Patients with hypermobility of the patella may develop chondromalacia and early osteoarthritis.
Approximately 13% of persons with DS have signs of AAI, while 1.5% have actual symptoms.19 Patients who are symptomatic require surgical stabilization. Although the management of asymptomatic patients with AAI is controversial, precautions such as avoiding contact sports or other activities that can maximize neck flexion are generally recommended. Family members or caregivers should be advised to watch for symptoms of spinal cord compression, while an annual neurologic examination is necessary to check for signs of upper motor neuron impingement. Radiologic screening for AAI is recommended in patients who wish to participate in the Special Olympics.5 Reproductive healthWomen with DS do have children.21 A woman with DS has a 50% chance of bearing children with DS, and offspring born without DS are more likely to have other congenital abnormalities than are the children of women without DS. Sexually active women should have pelvic examinations every 1 to 3 years. The DS patient requiring a pelvic examination may present a challenge.22 The clinician may want to wait until the second or third visit in order to establish a degree of patient trust. Nursing personnel may assist by using lifelike dolls and gentle persuasion to depict the examination. If the patient has difficulty during the examination, a fingertip Pap test—instead of one performed with a vaginal speculum—may be done. This procedure is accomplished by first inserting one finger into the vagina to locate the cervical os and then using the opposite hand to slide the cytology brush along the inserted finger into the os.4 Consider pelvic ultrasonography when a GU or bimanual examination is not possible and a pelvic mass or other abnormality is suspected. Most men with DS are infertile. Erectile dysfunction, inability to produce ejaculate, azoospermia, and inadequate sperm count contribute to male infertility.23 Males with DS have hypogonadism, and cryptorchidism occurs in up to 50% of this population, while studies have estimated the risk for testicular germ cell tumors (TGCT) to be 50 times greater than in the general population.23,24 Among patients with TGCT in an undescended testis, 20% will also have TGCT in the contralateral descended testicle. Additional risk factors to cryptorchidism causing TGCT may be an excess of gonadotropic hormone and an excess of genetic material in chromosome 21 that contributes to embryonic development. Most of these cancers are seminomas, which are curable when detected early. One literature review found the mean age for diagnosis of testicular seminoma to be 32 years.25 Orchidopexy is performed in the patient with cryptorchidism to allow for subsequent testicular examination. The importance of performing an annual testicular examination in males with DS cannot be overstated.
Mental healthTransitional situations such as a change in residence, the loss of a family member, or the responsibilities of new employment may overwhelm the DS patient.4 Planning with a family member or caregiver before a transition may alleviate patient stress and allow changes to occur smoothly. Behavior disorders or changes in mental status present a unique diagnostic challenge. The clinician’s knowledge of common coexisting mental illnesses may be helpful if a medical workup fails to yield a diagnosis. Studies estimate that 25% to 30% of adults with DS have psychiatric disorders.27 Dementia, depression, conduct disorders, and obsessivecompulsive disorder are common findings, while schizophrenia, alcoholism, and substance abuse are rare. Brain autopsy studies show that neuropathologic changes consistent with Alzheimer’s disease are present in nearly all DS patients older than 40 years, regardless of the cause of death.28 In addition, the gene for amyloid protein precursor (APP) is found on chromosome 21. As a result of extra chromosome 21, APP may produce amyloid beta 42, the neurotoxic fragment linked to Alzheimer’s disease, in greater amounts in persons with DS.29 Despite this evidence, a clinical dementia of the Alzheimer’s type (DAT) has been difficult to document because of the poor verbal expression, underlying mental retardation, and wide variation in function among people with DS. One prospective study of 96 institutionalized and community-based DS patients found the average age of DAT onset to be 54.2 years plus or minus 6.1 years.30 The range of onset among males was 48 to 68 years and among females 43 to 66 years. The prevalence for dementia in the surviving 73 patients in this longitudinal study was 8% in the 35- to 49-year-old age range, 55% in those 50 to 59 years old, and 75% in those older than 65.
Alzheimer’s may be difficult to distinguish from other mental health disorders.32 Symptoms such as aggression, irritability, mood swings, apathy or indifference, and memory loss may occur in depression and DAT. Furthermore, the two disorders may coexist in the same patient. Self-talk or soliloquy is common, particularly in stressful situations;4 it is sometimes incorrectly considered hallucinatory behavior in the DS patient. The high prevalence of depression and obsessive behaviors suggests changes in serotonin function. Case studies have shown selective serotonin reuptake inhibitors (SSRIs) to be effective in treating compulsive disorders and slowing cognitive decline in patients suspected of having DAT with a depressive component.32 Tricyclic antidepressants have increased anticholinergic effects in patients with DS. In one study, the duration of Alzheimer’s disease in patients with DS averaged 4.6 years from diagnosis, with a variation in life expectancy plus or minus 3.2 years.30 Decline in cognitive function may be screened for and monitored by the Alzheimer’s functional assessment tool,29 which requires caregivers to describe changes in activities of daily living over time. Medications that may be helpful but have not been studied in DS patients are cholinesterase inhibitors, antioxidants, estrogen replacement, and NSAIDs.29 Ancillary careDS patients have a variety of needs that should be monitored and coordinated by the primary care provider. Local support groups may be found through organizations such as the National Down Syndrome Society (www.ndss.org). Additional specialty care may be necessary for nutrition counseling, occupational therapy, and social services. Independent but supervised living is important in long-term planning. ConclusionSignificant improvements in medical care in recent decades have increased the life expectancy of DS patients, resulting in their need for more extensive health care services in the family practice setting. When evaluating behavioral changes or cognitive decline in the DS patient, the PA should consider reversible health conditions in the differential diagnosis. Health Care Guidelines for Individuals with Down Syndrome provides a useful format for interval assessment of the DS patient. The primary care provider should integrate and coordinate specialty care for the longterm needs of the patient. REFERENCES
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Persons with DS should receive the usual preventive medical care provided to the general population. In addition, a comprehensive text of guidelines for routine care in pediatric and adult patients is available in Health Care Guidelines for Individuals with Down Syndrome, from the Down Syndrome Medical Interest Group.5 Table 1 lists medical conditions associated with DS that require frequent assessment. 
Atlantoaxial instability (AAI) is a potentially critical problem involving the transverse ligaments of the first and second cervical vertebrae.19 DS patients who present with a history of neck injury or pain should be examined for signs and symptoms of spinal cord compression (see Table 2). Similarly, patients who request clearance for physical activities such as the Special Olympics, or who require general anesthesia, should be quesioned carefully for a history of head and neck injury or symptoms of AAI. Obtain plain films of the cervical spine in the neutral, flexed, and extended positions; a distance on any view that is greater than 5 mm between the posterior surface of the anterior arch of the atlas and the anterior aspect of the odontoid process is diagnostic for AAI.20
Most persons with DS have the capacity for awareness and learning about socialization and issues of sexuality.26 Among the mentally handicapped, rape and incest may occur early in adolescence and at higher rates than in the general population.22 Contraception for a DS patient is thus a major concern of parents and caregivers. Additionally, there are many preventive and acute reasons why referral to a reproductive health clinic for the handicapped may be necessary (see Table 3). 
As with the general population, DAT in trisomy 21 is a diagnosis of exclusion. Table 4 lists the studies that help evaluate reversible causes of behavioral change or cognitive decline in people with DS. Hearing loss can be misinterpreted as a clinical sign of dementia and can also contribute to delirium. Infection, anemia, vitamin deficiency, and thyroid and metabolic disorders may also result in mental status changes. Cranial MRI or CT can rule out an intracranial lesion. Traditional neuropsychologic testing for Alzheimer’s disease is not really helpful in the DS population; the clinical presentation of DAT may be more advanced than in the general population because of poor verbal expression and an environment that may not require an active, engaging memory. The clinical evaluation for DAT should focus on behavior that is progressive and irreversible,31 including progressive declines in function and memory loss, gait apraxia, incontinence of urine or stool, dysphagia with choking, and seizures.