Complications
About 50% of people with Down syndrome (DS) have congenital heart disease (CHD).[17][29][30] Atrioventricular septal defect is the most common form of CHD in DS (31% to 61% in population-based studies of CHD subtypes in DS), with a much higher prevalence than in the general population.[32]
Evaluation by a pediatric cardiologist, including an echocardiogram, is recommended in all newborns with DS (even in the absence of a murmur).[17][29][30]
Children with Down syndrome (DS) may have shorter arms and legs than age-matched peers without DS. Their growth rate and height may be decreased. Likelihood for obesity may be greater, possibly caused by inactivity and low muscle tone.
Weight, length, weight-for-length, head circumference, and BMI should be measured at each well-child visit throughout childhood and adolescence.[17]
Infants with Down syndrome (DS) can be born with transient myeloproliferative disorder which is a form of leukemia. Children with DS have a higher risk of acute myeloid leukemia (AML) than the general population, with a median onset of 2 years compared with 8 years in the general population. Most cases of AML in children with DS occur between the ages of 1 and 5 years, with an average age of 2 years. After age 3 years, acute lymphocytic leukemia (ALL) occurs more frequently, with most cases occurring by age 6 years. Children with DS are more responsive to certain forms of chemotherapy, and disease resistance and recurrence are uncommon.
After age 3 years, acute lymphocytic leukemia (ALL) occurs more frequently than acute myeloid leukemia (AML), with most cases occurring by age 6 years. Children with DS are more responsive to certain forms of chemotherapy, and disease resistance and recurrence are uncommon.
Much more common and earlier age of onset than in the general population. Pathologic findings are present in the brain of nearly all people with Down syndrome (DS) by age 40, although not all will display signs of Alzheimer disease. The average age of onset is 54.5 years.[74] Adults with DS and suspected or possible Alzheimer disease may show significant decline in cognitive abilities as well.[75]
A rare but increasingly recognized cause of developmental regression in teens and young adults with Down syndrome. Can include loss of previously acquired developmental skills, catatonia, agitation, hallucination, depersonalization.[73]
Develops in about 10% of infants with Down syndrome. Typically resolves spontaneously within 3 months. Despite most infants with transient leukemia recovering on their own, 20% to 30% of these cases will later be diagnosed with a more serious disease, acute megakaryocytic leukemia (AMLK), which is a subtype of acute myeloid leukemia (AML).[62][78]
Adults with Down syndrome (DS) have a lower rate of psychiatric disorders than adults with other cognitive disabilities. However, depression in adults with DS is estimated to be about 11% and may be attributed to several factors: challenges in transitioning from childhood to adulthood, increased awareness that they are different and may change, loss of personal relationship with their peers, obesity leading to a sedentary lifestyle, poor diet, limited exercise and/or social activity, and medical complications such as hypothyroidism and obstructive sleep apnea.[77]
Many children with Down syndrome have global developmental delay. Cognitive abilities vary greatly, with challenges in the expressive language domain compared with receptive language. IQ can range from mild to moderate intellectual disability, between 40 and 72.
Chronic ear disease and hearing loss can further affect language development.[69]
Ongoing developmental assessment and psychoeducational evaluation is recommended.
An estimated 30% to 60% of children with Down syndrome (DS) have obstructive sleep apnea. Predisposing factors include small upper airway, midface and mandibular hypoplasia, large adenoids, protruding tongue, hypotonia, and obesity.[69]
Referral for a sleep study or polysomnogram for all children with DS is recommended between 3 and 4 years of age.[17] Appropriate therapies may include tonsillectomy/adenoidectomy or supplemental oxygen during sleep.[70] Physicians are encouraged to discuss symptoms of sleep problems at every well-child care visit.
Adults with DS have more predisposing factors for obstructive sleep apnea than children with DS, as they will have the craniofacial anomalies, and are also more likely to be obese or have hypothyroidism. Adults with DS who have obstructive sleep apnea may also have signs of hypoxemia, hypoventilation, and sleep fragmentation, which may increase their risk for cardiovascular and neurologic complications.[71]
The higher frequency of (mostly conductive) hearing loss in children with Down syndrome (DS) is secondary to their anatomic anomalies, including midface hypoplasia, easily collapsible eustachian tube, stenotic ear canals, and small external canal.
Hearing screen is required in all newborns in general. Hearing evaluations should be repeated at 6 months, 12 months, and once a year thereafter.[17]
Referral to a pediatric otolaryngologist is recommended if the tympanic membrane is not visualized and/or otitis media recurs frequently.[17]
Aggressive interventions, both medical and surgical, have led to decreased incidence of hearing loss, good control of chronic rhinitis, and timely diagnosis of sleep-disordered breathing in individuals with DS.[69]
In general, placement of myringotomy tubes are considered if there are >4 ear infections in 6 months, >6 ear infections in 1 year, or persistent middle ear fluid for 3 consecutive months.[33] Additionally, as children with DS are prone to chronic ear disease, it will be important to assess the need for multiple sets of myringotomy tubes.
Interval ear examinations (i.e., every 3-6 months) may need to be performed by the otolaryngologist until the tympanic membrane can be visualized by the pediatrician and tympanometry can be performed reliably.[17]
The immune system in children with Down syndrome has clinical and laboratory differences that predisposes children to a higher incidence of upper respiratory tract infections, chronic middle ear effusions, and chronic otitis media.
Hypothyroidism is particularly common in Down syndrome (16% to 20%) and may be detected by newborn screening or during yearly routine screening.
Hyperthyroidism occurs at a lower frequency than hypothyroidism.[29][34]
All newborns are required to have a newborn screening, including thyroid testing. If the screen is normal, a follow-up for thyroid function with thyroid-stimulating hormone measurements at 6 months, 12 months, and then yearly is recommended throughout childhood and adolescence. More frequent thyroid tests (i.e., every 6 months) are indicated if antithyroid antibodies are detected at any point.[17]
As a result of low resting metabolic rates, about one half of all girls with DS are overweight by the third year of life and one half of all boys with Down syndrome are overweight by early childhood (3-8 years of age).[72]
Refer to a physician with expertise in pediatric sleep for any child with signs or symptoms of obstructive sleep apnea or abnormal sleep study result. Discuss obesity as a risk factor for sleep apnea.[17]
Consistent exercise and a balanced diet are recommended. Routinely screening for obesity and sleep apnea is important.[17]
Congenital cataracts are seen in 4% of children with Down syndrome (DS).[5] Nasolacrimal duct may be obstructed as a complication of midface hypoplasia but it improves with age.
Other abnormalities include strabismus (23% to 44%), accommodative esotropia, myopia, hyperopia, and blepharitis.[34]
Children with DS should have an ophthalmic evaluation with photoscreening at each well-child visit. Abnormal findings or lack of access to photoscreening should prompt referral to a pediatric ophthalmologist. If lacrimal duct obstruction is present, refer for evaluation for surgical repair of the drainage system if not resolved by 9-12 months of age.[17]
Include delayed primary and secondary dentition, missing teeth, small or misshapen teeth, or severe crowding as a result of small oral cavity.[34] Average age of eruption of the first tooth is between 12 and 20 months, as compared with 6 months in typically developing children.
Skin disorders such as xerosis, hair thinning, alopecia areata, vitiligo, folliculitis, and keratosis pilaris are common in children with Down syndrome, and parents and pediatricians should be attentive to signs and symptoms. Xerosis and hair thinning could be a sign of hypothyroidism and may warrant an interim thyroid function test.[17]
Patients with behavioral problems, including inattention, hyperactivity, or withdrawal, should receive a behavioral assessment and tailored behavioral intervention. In certain cases, psychopharmacological intervention may be necessary and should be explored with the child's primary care physician and/or child psychiatrist or developmental-behavioral pediatrician.
Present in <1% of individuals with Down syndrome.[17]
May be indicated by history of chronic constipation not responding to diet change or stool softeners.
Caused by intolerance to gluten (a protein in wheat, rye, barley, and possibly oats). Damages the small intestine and prevents absorption of nutrients from food.
Occurs in 7% to 16% of individuals with Down syndrome (DS) and may present with diarrhea, bloating, or growth failure. About one third of individuals with DS who have celiac disease may not manifest gastrointestinal signs and symptoms.[29][34]
Screening for total immunoglobulin A and anti-tissue transglutaminase antibodies is recommended if symptoms associated with celiac disease are noted.[17]
Present in 7% to 19% of children with Down syndrome (DS), although most studies are limited by sample size and ascertainment bias.[76][77]
As for all children, children with DS should be screened for autism spectrum disorder (ASD) between 18 and 24 months of age. If there is suspicion of ASD, early referral to a specialist is imperative.[17]
About 15% of patients have lax atlantoaxial joints (atlantodens interval >4.5 mm on the lateral spine radiograph in flexion, neutral, and extension view). May result in spinal cord compression in 1% to 2% of cases.
In terms of atlantoaxial subluxation, symptoms of myelopathy should be sought, including neck pain/stiffness, changes in head positioning or torticollis, spasticity or change in tone, radiculopathy, changes to gait loss or previously attained bowel/bladder control, or hyperreflexia. Cervical spine x-ray is indicated if symptoms are present. A careful history and physical is important at all health maintenance exams.[17]
Musculoskeletal disorders, such as ligamentous laxity and low muscle tone, may contribute to knee and hip problems, and increase susceptibility to subluxation and dislocations.[34]
Children with Down syndrome are not at increased risk of solid tumors with the exception of testicular cancer.[80]
For this reason, the testes should be palpated in males at each well-child visit to check for lumps or swelling. Testicular self exams should be taught to adolescents and adults with Down syndrome or to their trusted caregivers.
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