Chapter 81 Turner Syndrome
PATHOPHYSIOLOGY
Turner syndrome is a genetic condition that occurs only in females, in which there is an X chromosome missing or abnormally structured. This results in short stature, ovarian dysgenesis, and infertility. It was first observed by Henry Turner in 1938, when he treated seven female patients for dwarfism and lack of sexual development. Through the years, the knowledge base about Turner syndrome has increased dramatically. Early treatments with pituitary extracts were ineffective; however, current treatments with growth hormone injections and other hormone therapies are creating much more positive outcomes for these girls.
The chromosomal abnormality occurs on chromosome 45. It can be a complete absence of X, a structural abnormality with partial deletion of X, or mosaicism, which is a mixture of the two. In mosaicism, some cells will have the typical 46 chromosomes and some will have 45. The gene has been identified at the SHOX or short stature homeobox–containing gene. Two copies of the SHOX gene are required for normal growth.
Girls with Turner syndrome may or may not be diagnosed in infancy. There may be a slight intrauterine growth restriction, and growth may be slow during infancy in early childhood.
There will be no pubertal growth spurt. Many body systems are affected by Turner syndrome, although not all girls with the syndrome will have all manifestations.
COMPLICATIONS
1. Cardiovascular: occurs in one of three girls, left-sided anomalies such as coarctation of the aorta and abnormalities of the aortic valve are the most common.
2. Neurologic: often have normal intelligence but may have difficulty with memory, attention, visual processing, and math. Psychosocial issues result from short stature and typical facial features that may cause teasing in school. Behavioral disorders may result from issues regarding self-esteem.
3. Renal: may have horseshoe kidney or malrotated kidney; does not affect renal function but may predispose the girl to urinary tract infections.
4. Musculoskeletal: short neck occurs in about 40%, owing to hypoplasia of cervical vertebra. Scoliosis, kyphosis, or lordosis may occur less commonly.
5. Endocrine: lack of secretion of growth hormone; no estrogen or other female hormones as a result of ovarian dysgenesis. Puberty is delayed or absent, infertility is common, premature menopause may occur. Hypothyroid conditions may also occur.
6. Lymph: lymphedema and cellular migration cause many features of Turner syndrome. The lymphedema occurs in 1 of every 3 infants affected; improves with age; may recur at puberty.
7. Nail dysplasia occurs in 50%, with small, narrow, hyperconvex nails, inserted at an acute angle; webbed neck occurs in about 25% and develops prenatally; low posterior hairline, bushy eyebrows, and low-set, posterior, rotated ears are common. Shield-shaped chest and widely spaced nipples are result of stretching of rib cage from fetal edema.
8. Sensory: strabismus or ptosis may be noted; recurrent otitis media occurs in 75% of cases and is related to anatomic differences.
9. Dermatology: nevi are common.
10. Orthopedic: hallmark of Turner syndrome is short stature; there is delay in skeletal maturation, and bone size is smaller. Bone mineral density is decreased. There may be a shortening of the fourth metacarpal; knee abnormalities are seen in 60% of patients, scoliosis in 12%, and increased carrying angle of arms (cubitus valgus) in 45%. High arched palate and small chin are characteristic features.
LABORATORY AND DIAGNOSTIC TESTS
1. Diagnosis is made by karyotype of chromosomal patterns—results will show a single X chromosome and absence of all or part of the second sex chromosome. Absence of X accounts for about 60% of Turner syndrome cases, and is known as 45,X.
2. A karyotype gene was recently identified as being responsible for part of the short stature in girls with Turner syndrome. It is known as the short stature homeobox (SHOX)–containing gene. This gene accounts for some of the short stature and the skeletal abnormalities.
MEDICAL MANAGEMENT
Nurses caring for children with Turner syndrome are most likely to see them in the hospital or the outpatient setting for other procedures or care. Medical management of a girl with Turner syndrome is very complex. It requires first a suspicion of the syndrome to lead to diagnosis. Diagnosis is based upon karyotype of chromosomes, which can be done prenatally with chorionic villus sampling or amniocentesis, and postnatally with a blood test. Most often, Turner syndrome is not diagnosed in infancy, and is suspected later in childhood because of growth failure. At that time, a very thorough work-up should be done.
Depending on the degree of involvement of different clinical manifestations, the long term management may require several specialists. At the least, a pediatric endocrinologist should be involved in management of growth hormone and other hormone replacement therapy.
Since most girls with Turner syndrome have short stature, growth hormone therapy has become the standard of care. This therapy is usually started after the child falls below the 5th percentile for age. Some will reach this marker at 2 years, and many girls start growth hormone at this time. It is generally thought that a minimum of 6 years of growth hormone therapy is required for a girl to reach maximal height.
Cardiovascular abnormalities are treated based upon etiology. Usually, the left side of the heart is involved. Common defects such as bicuspid aortic valve and coarctation of the aorta are repaired surgically as needed. Most girls with Turner syndrome and accompanying cardiovascular anomalies require prophylactic administration of antibiotics for dental or surgical procedure. Some girls with Turner syndrome will also develop hypertension. Careful monitoring of cardiovascular status is important as part of well-child exams.
Other sensory issues should be assessed and monitored routinely. There may be vision and/or hearing difficulties. Referral to an ophthalmologist for initial evaluation at time of diagnosis (if not made prenatally or after birth) should be considered for all affected girls. Regular hearing assessments should be part of all well-child exams.
Since there are a variety of other problems occurring with Turner syndrome, such as craniofacial abnormalities, thyroid dysfunction, obesity, orthopedic problems, and carbohydrate metabolism difficulties, it is crucial that the health care provider monitoring the child with this syndrome be aware of these and manage or refer as appropriate. This child should have annual well-child exams to screen for other issues that may arise throughout childhood. Support groups for girls with Turner syndrome can be invaluable in dealing with self-esteem and other psychosocial issues. Working with the educational team and school nurse at the child’s school can facilitate school success for the girl with Turner syndrome.
NURSING ASSESSMENT
1. Cardiovascular: auscultate for murmurs indicative of coarctation of the aorta or other left sided cardiac anomalies.
2. Neurologic: assess for possible difficulties in learning at school.
3. Renal: monitor for increased incidence of urinary tract infections.
4. Musculoskeletal: look for typical facial features as described above, along with typical hand features, cubitus valgus, and short stature.
5. Endocrine: monitor for delayed puberty and lack of growth spurt.
NURSING DIAGNOSES
NURSING INTERVENTIONS
1. Demonstrate acceptance of the child and family during admission or outpatient care.
2. Educate child (if developmentally appropriate) and parents about Turner syndrome multisystem involvement and potential problems to watch for; provide information regarding support groups and websites with accurate and complete information.
3. Teach child (if developmentally appropriate) and parent about administration of growth hormone injections and other hormonal supplements.
4. Encourage parents to work with school system regarding best possible educational situation for child.
5. Provide education and appropriate nursing care for other affected systems; will need to be individualized based upon organ and/or system involvement for each patient; that is, postoperative care after cardiac surgery, information regarding orthopedic issues such as scoliosis treatment, education regarding thyroid medications and hormone replacement therapy, and so on.
Discharge Planning and Home Care
1. Ensure that parents and child have adequate supplies for administration of growth hormone and other medications, and that they have demonstrated proficiency in administering these.
2. Ensure that parents and child are adequately educated regarding the multisystem involvement with Turner syndrome.
3. Ensure that parents are connected with appropriate referral and support systems (e.g., pediatric endocrinologist, Turner syndrome support group).
CLIENT OUTCOMES
1. Child will experience adequate growth and development based upon treatment with growth hormone injections and other hormonal support.
2. Child will maintain good state of health (adequate cardiac output, minimal urinary tract infections, good self-esteem) based upon clinical manifestations present.
Barclay L. Growth hormone supplementation may be helpful in Turner syndrome. [(serial online)] .Medscape, 2005. www.medscape.com/viewarticle/501983. Accessed December 29
Frias JL, Davenport ML. Health supervision for children with Turner syndrome. Pediatrics. 2003;111(3):692.
National Institutes of Health [(website)] .Table 1. Incidence of phenotypes, 2006. http://turners.nichd.nih.gov/ClinFrTables.html. Accessed January 14
Ross JL, St. Dennis-Feezle LK, Weber C. Turner syndrome: Toward early recognition and improved outcomes. [(serial online)] .Medscape, 2005. www.medscape.com/viewprogram/2115_pnt. Accessed December 29
Rudy C. When will I start my periods? J Pediatr Health Care. 2004;18(1):39.
Turner Syndrome Society [(website):] .Turner Syndrome Society, 2006. www.turner-syndrome-us.org. Accessed January 14
