Description/EtiologyDown syndrome (DS) is a chromosomal disorder marked by mental retardation (IQ scores usually range from 20–80, with a mean of ~ 50), dysmorphic facial features, and numerous other distinctive phenotypic characteristics. DS is the most common genetic cause of intellectual disability.

Most cases of DS are caused by the abnormal presence of three copies of chromosome 21 in every cell in the body (known as trisomy 21). In some cases, DS is due to the presence of an extra chromosome in only some cells (mosaic trisomy 21) or due to an extra copy or portion of chromosome 21 being attached to another chromosome (translocation trisomy 21). DS affects almost every organ system and can cause a number of cognitive and physical impairments, including hearing and visual deficits, congenital heart defects (CHDs), autism, depression, celiac disease, and early-onset Alzheimer’s disease.

Prenatal diagnosis is possible via amniocentesis, chorionic villus sampling, or percutaneous umbilical blood sampling. Because these tests are invasive, an individualized risk assessment based on maternal age, maternal serum markers (e.g., serum alpha-fetoprotein), and fetal physical markers (e.g., nuchal translucency on ultrasonography) may be done to determine elevated risk and the need for further testing. If not diagnosed prenatally, DS is usually suspected and diagnosed at birth, based on clinical features and cytogenetic studies, respectively.

The level of disability of persons with DS varies; some children require placement in specialized residential settings that provide intensive supervision and well-structured routines, while many others are able to remain with their families and develop good social skills and a reasonable degree of independence. Treatment depends on the type and level of disability, and commonly involves a team of clinician specialists in cardiology, ophthalmology, orthopedics, neurology, audiology, physical and occupational therapy, speech-language therapy, nutrition, and mental health.

Facts and FiguresDS accounts for approximately one-third of cases of moderate-to-severe mental retardation. The estimated incidence of DS in the United States is 1 in 800 live births. The condition affects males slightly more often than females (1.2:1). Full trisomy 21 is the cause in ~ 94% of cases. Approximately 75% of concepti with trisomy 21 die in utero. CHDs are present in 40–50% of affected individuals, and are the primary cause of early mortality in patients with DS. Approximately 5–10% of affected infants have seizures. Up to 38% of people with DS have a comorbid psychiatric condition, such as attention deficit hyperactivity disorder, autism, depression, or obsessive-compulsive disorder. DS is associated with a 12-fold increase in the risk for infectious disease, particularly pneumonia. Risk for developing leukemia in the first 5 years of life is increased 56-fold in children with DS. Clinical Alzheimer’s disease affects at least one-third of patients with DS after age 35. An estimated 85% of infants born with DS survive to 1 year of age; 50% can be expected to live longer than 50 years.

Risk FactorsThe risk of having a child with DS increases with increasing maternal age. A 35-year-old woman who becomes pregnant has a risk of 1:385 of having a child with DS; the risk increases to 1:106 in a 40-year-old woman and to 1:30 in a 45-year-old woman.

Signs and Symptoms/Clinical PresentationDS is associated with numerous signs/symptoms and medical conditions. Physical signs characteristic of DS include a flat face, slanted eyes with epicanthal folds, deep crease in the palm of the hand, small ears, short neck, sparse hair and eyelashes, white spots on the iris, protruding tongue, brachycephaly, wide/flat nasal bridge, and undescended testicles in males. Infants may present with hypotonicity and seizure disorder. Additional manifestations include CHDs, endocarditis, hypothyroidism, chronic constipation, hearing loss, vision impairment, atlantoaxial instability (AAI; i.e., a condition affecting the two bones at the top of the spinal cord [C1 and C2], which, because of stretchier ligaments, are prone to excessive movement that may affect the underlying nerves and lead to serious neurological problems), celiac disease, duodenal atresia/stenosis, atopic dermatitis, upper respiratory infections (URIs), ear infections, obesity, and/or obstructive sleep apnea. Delays in speech and language development are common. Premature aging characterized by skin wrinkling, early graying and loss of hair, hypogonadism, cataracts, hearing loss, neoplasms, and degenerative vascular disease may occur in adolescents and adults with DS.

AssessmentPatient History 4

Assess feeding/diet history, and for hearing and vision problems, speech/language and motor delays, history •of URIs, gastrointestinal (GI) disturbances, sleep problems, and comorbid mental disordersSeptember 9, 2011

ICD-9758.0

ICD-10-CANQ90

AuthorsSuzanne Pinto, MSW

Tanja Schub, BS

ReviewersKathleen Walsh, RN, MSN, CCRN

Cinahl Information Systems

Glendale, California

Eliza Schub, BSN, RNCinahl Information Systems

Glendale, California

Nursing Practice CouncilGlendale Adventist Medical Center

Glendale, California

EditorDiane Pravikoff, RN, PhD, FAAN

Cinahl Information Systems

Down Syndrome

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Published by Cinahl Information Systems. Copyright©2011, Cinahl Information Systems. All rights reserved. No part of this may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. Cinahl Information Systems accepts no liability for advice or information given herein or errors/omissions in the text. It is merely intended as a general informational overview of the subject for the healthcare professional. Cinahl Information Systems, 1509 Wilson Terrace, Glendale, CA 91206

Physical Findings of Particular Interest 4Ultrasound-based nuchal translucency screening at 11-14 weeks’ gestation may show abnormally high fluid level at nuchal fold of fetus, indicating •increased fetal risk for trisomy 21 or other genetic disorder

Laboratory Tests That May Be Ordered 4Cytogenetic study/chromosomal (i.e., karyotype) analysis will confirm diagnosis •

Other Diagnostic Tests/Studies 4Echocardiogram may show cardiac anomalies; X-ray, CT scan, or MRI may reveal AAI (usually evaluated at age 3 years) •Other studies may be ordered throughout the lifespan to assess for DS-associated conditions (e.g., thyroid studies) •

Treatment GoalsAssist with Treatment of Neonate, Promote Optimum Physiologic Function, and Educate Family 4Members About Manifestations of DS and Associated Special Needs of Child

Assist with neonate resuscitation, as appropriate; monitor vital signs, assess all physiologic systems, and review laboratory/diagnostic study results; •immediately report abnormalities and assist with prescribed treatment, as appropriateEducate parents about feeding the neonate, and reassure that the infant’s inability to breastfeed is usual in DS due to poor sucking reflexes, a protruding •tongue, and nasal congestion; provide a specialized bottle and educate parents/caregivers about its use, and request referral to a dietitian or clinical nurse specialist for additional feeding support, if available; educate parents about the benefits of swaddling to provide comfort and prevent musculoskeletal injury related to hypotonicity Assess parental anxiety and coping ability; educate and encourage discussion about diagnostic procedures (e.g., EKG, thyroid testing), treatment (e.g., •surgery) risks and benefits, potential developmental deficits (e.g., physical, cognitive, emotional, social), and individualized prognosis

Request family member referral to a social worker for identification of local resources for immediate and future needs, including subsidized –evaluation and medical/mental health care, residential/long-term care placement, special education, physical/occupational/speech therapy, support groups, and DS organizations

Promote Physical and Psychological Well-Being During Childhood and Adulthood 4Monitor all physiologic systems, including hearing and vision (evaluated every 2 years), oral/dental, skin, cardiac, and musculoskeletal; report •abnormalities and treat, as orderedAdminister and educate about the necessity for medications prescribed for DS-related medical conditions, including thyroid hormone for •hypothyroidism; diuretics and digoxin for heart failure (HF); antibiotics for subacute bacterial endocarditis, URIs, ear infections or pneumonia; pneumococcal vaccine; and anticonvulsants to treat seizure disorder Assess coping ability and provide emotional support to patient and family; educate and encourage discussion about the importance of following a healthy •diet/lifestyle (including engaging in regular physical activity) and adhering to regular dental/physical/mental health check-ups; when discussing growth and development, use standardized charts modified for individuals with DS

Food for ThoughtWomen’s perception of the risk of having a child with DS does not always reflect actual risk, and giving a numerical risk score may not be helpful; 4caregivers should ensure that pregnant women correctly interpret risk informationUse of maternal plasma DNA sequencing to rule out fetal trisomy 21 in high-risk pregnancies could obviate the need for approximately 98% of invasive 4diagnostic procedures (i.e., amniocentesis and chorionic villus sampling) (Chiu et al., 2011)

Red FlagsDelayed recognition of AAI in patients with DS may lead to irreversible spinal cord damage; X-rays should be taken prior to surgical/chiropractic 4procedures and participation in sports Children with DS who develop leukemia are more sensitive to effects of some chemotherapeutic agents (e.g., methotrexate) than other children, so careful 4monitoring for toxicity is essential Patients with DS are at increased risk for anesthetic complications, including bradycardia, airway obstruction, difficult endotracheal intubation, and 4postintubation croup

What Do I Need to Tell the Patient/Patient’s Family?When possible, provide written information to reinforce verbal education, including information on assessing for signs of medical and psychological 4complications of DS and seeking immediate medical attention for new or worsening signs and symptoms Encourage obtaining more information from the National Down Syndrome Society at 4 www.ndss.org and from the National Association for Down Syndrome at www.nads.org

ReferencesChen, H. (2011). Genetics of Down syndrome. • Medscape Reference. Retrieved July 6, 2011, from http://emedicine.medscape.com/article/943216-overviewChiu, R. W., Akolekar, R., Zheng, Y. W., Leung, T. Y., Sun, H., Chan, K. C., … Lo, Y. M. (2011). Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma DNA sequencing: Large scale validity study. • BMJ, 342, c7401. DynaMed. (2011, May 9). • Down syndrome. Ipswich, MA: EBSCO Publishing. Retrieved July 6, 2011, from http://search.ebscohost.com/login.aspx?direct=true&site=dynamed&id=AN+115414Roberts, M., & Hay, B. N. (2010). Down syndrome. In F. J. Domino (Ed.), • The 5-minute clinical consult 2011 (19th ed., pp. 412-413). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.