Turner syndrome is caused by the absence of one set of genes from the short arm of one X chromosome.
What is Turner Syndrome?
Turner syndrome is one of the most common chromosomal abnormalities.
- Turner syndrome is caused by the absence of one set of genes from the short arm of one X chromosome.
- In 1938, Henry Turner first described Turner syndrome, which is one of the most common chromosomal abnormalities.
- More than 95% of adult women with Turner syndrome exhibit short stature and infertility.
Turner syndrome’s pathophysiology is as follows:
- Turner syndrome is caused by the absence of one set of genes from the short arm of one X chromosome.
- In patients with 45,X karyotype, about two-thirds are missing the paternal X chromosome.
- In addition to monosomy X, a similar clinical picture is found with a 46,XXiq karyotype and in some individuals with mosaic karyotypes.
- A deletion of the SHOX gene can cause a similar skeletal phenotype known as Leri-Weill dyschondrosteosis (LWD).
Statistics and Incidences
The statistics of Turner syndrome in the United States and worldwide include the following:
- The frequency of Turner syndrome is approximately 1 in 2000 live-born female infants.
- As many as 15% of spontaneous abortions have a 45,X karyotype.
- Interestingly, 99% of conceptions with 45,X karyotypes spontaneously abort.
- Turner syndrome only occurs in females; Noonan syndrome, sometimes inappropriately called male Turner syndrome, can occur in males or females.
The diagnosis of Turner syndrome requires the presence of typical phenotypic features and the complete or partial absence of a second sex chromosome.
- Maternal chromosomes. In patients with a single X chromosome, the chromosome is of maternal origin in two-thirds of cases.
- Lack of SHOX gene. Many of the features of Turner syndrome, including the short stature, are due to the lack of a second SHOX gene, which is on the X chromosome.
The signs and symptoms of Turner syndrome from infants to adolescents are:
- Lymphedema. At birth, girls with Turner syndrome may have swollen hands and feet because of lymphedema.
- Sausage-like fingers and toes. In infants, the combination of dysplastic or hypoplastic nails and lymphedema gives a characteristic sausage-like appearance to the fingers and toes.
- Short stature. Growth rate in childhood is slightly slower; before age 11 years, some girls have height and growth rates that are well within the normal range, but heights are typically below the 50th percentile.
- Dental symptoms. A high arched palate suggests the diagnosis; patients may have dental crowding or malocclusion.
- Ovarian failure. Suspect ovarian failure in girls who have no breast development by age 12 years or who have not started menses by age 14 years; elevated levels of luteinizing hormone (LH) and FSH confirm ovarian failure.
- Webbed neck. Lymphedema in utero can cause a broad neck and a low or indistinct hairline.
- Shield chest. The chest appears to be broad with widely spaced nipples; this may be caused in part by a short sternum.
- Cutis laxa. Loose folds of skin, particularly in the neck, are signs in newborns; this is a result of resolving lymphedema and occasionally is observed after infancy.
Assessment and Diagnostic Findings
The diagnosis of Turner syndrome is made through the following:
- Prenatal tests. On fetal ultrasonography, Turner syndrome is suggested by the presence of a nuchal cystic hygroma, horseshoe kidney, left-sided cardiac anomalies, or nonimmune fetal hydrops; Turner syndrome may be prenatally diagnosed by amniocentesis or chorionic villous sampling; noninvasive prenatal testing of maternal blood can be used to screen for Turner syndrome with great sensitivity and specificity.
- Karyotyping. A standard 30-cell karyotype analysis is required for diagnosis of Turner syndrome, to exclude mosaicism; diagnosis is confirmed by the presence of a 45,X cell line or a cell line with deletion of the short arm of the X chromosome (Xp deletion); patients with Turner syndrome should be investigated for the presence of Y chromosomal material using a Y-centromeric probe.
- Gonadotropins. Both LH and FSH may be elevated in untreated patients younger than 4 years; they are later suppressed to normal or near-normal levels, only to rise to menopausal levels after age 10 years.
- Thyroid function tests. Because of the high prevalence of hypothyroidism in Turner syndrome, obtain thyroid function tests at diagnosis; repeat TSH measurements every 1-2 years or if symptoms develop, because hypothyroidism may develop at a later age.
- Glucose metabolism. Abnormalities of glucose metabolism, including overt diabetes mellitus, are more common than in unaffected children; screening for diabetes mellitus is best performed by obtaining a hemoglobin A1c or fasting glucose level; glucose tolerance tests should not be used for screening.
- Renal studies. At diagnosis, perform ultrasonography of the kidneys and renal collecting system; annual urine cultures and measurement of BUN and creatinine levels are recommended for those patients with abnormalities of the renal collecting system that predispose to obstruction.
- Cardiovascular studies. Perform echocardiography and/or MRI of the heart and aorta upon diagnosis; evaluate 4-limb blood pressures, because of the high incidence of coarctation of the aorta.
- Audiology. Infants diagnosed at birth should have a hearing assessment in the nursery; formal hearing assessment is recommended at age 1 year and before entering school; adults should have a hearing evaluation at least once, with further testing later if hearing loss is suspected.
Patients with Turner syndrome require screening for commonly associated chronic diseases; early preventive care and treatment are also essential.
- Growth hormone therapy. In childhood, growth hormone therapy is standard to prevent short stature as an adult; the ideal age for initiating treatment has not been established; taller adult heights occur with the longest treatment durations before the start of puberty.
- Sex hormone replacement therapy. Estrogen replacement therapy is usually required, but starting too early or using doses that are too high can compromise adult height; continuous low-dose estrogens can be cycled in a 3-weeks on, 1-week off regimen after 6-18 months; progestin can be added later; transdermal estrogens are associated with physiologic estrogen levels and may be the preferred treatment, if tolerated.
- Diet. Both short stature and ovarian failure are risk factors for osteoporosis, and care should be taken to ensure adequate daily intake of calcium (1.0-1.5 g) and vitamin D (at least 400 IU).
Medications can be used to help the child with Turner syndrome.
- Human growth hormone. These agents are the primary treatment for short stature; they stimulate the growth of linear bone, skeletal muscle, and organs.
- Anabolic steroids. This is an adjuvant for growth hormone therapy.
- Thyroid replacement therapies. These agents are used for the treatment of hypothyroidism.
- Estrogen replacement therapies. Almost all individuals require estrogen replacement; estrogen is usually started at chronologic age 12 years or older; adults usually require cyclic therapy with both estrogen and progestin; transdermal or parenteral estrogen may be useful in limiting some adverse effects of estrogen therapy.
- Antihypertensive agents. These products are used to control hypertension and to ultimately prevent complications such as aortic dissection.
- Vitamins and minerals. Vitamin D is a micronutrient essential for normal absorption of calcium and phosphorus; osteoporosis is common and is a major cause of morbidity in adults; treatment is the same as for other adult women with osteoporosis; monitor diet and ensure an intake of at least 1 g/d of calcium and 400 IU/d of vitamin D.
Nursing care of a child with Turner syndrome include:
Assessment in a child with Turner syndrome involves the following:
- History. Patients with Turner syndrome may present with a cystic hygroma on a fetal ultrasound or may have swollen hands and feet owing to lymphedema at birth; children usually present with short stature, but some girls younger than 11 years have heights within the normal range for girls without Turner syndrome; in older adolescents and adults, presenting symptoms usually involve issues of puberty and fertility as well as short stature.
- Physical examination. Approximately 95% of individuals with Turner syndrome have both short stature and signs of ovarian failure upon physical examination.
Based on the assessment data, the major nursing diagnoses are:
- Potential for low self-esteem related to body not developing secondary sex characteristics as peers of same age.
- Ineffective child/adolescent eating dynamics related to dental malocclusion.
- Disturbed body image related to differences in physical characteristics as evidenced by webbed neck, shield chest, and short stature.
- Risk for imbalanced nutrition, more than the body requires.
Nursing Care Planning and Goals
The major nursing care planning goals for patients with Turner syndrome are:
- Patient will identify feelings of perception of self.
- Patient will demonstrate behaviors to restore positive self-esteem.
- Patent will participate in treatment regimen to correct factors that precipitated crisis.
- Patient will participate in daily physical activity 60 minutes daily.
- Patient will learn how to make healthy food choices by naming the food groups.
Nursing interventions are:
- Improve self-esteem. Help patient identify feelings and express them; engage in active listening regarding student’s concerns and verbalizations; help student explore support system and mobilize other community resources or support groups related to Turner syndrome; encourage involvement in medical decisions about care to be offered.
- Improve physical health. Provide the patient with suggestions of physical activities, e.g., walking, bike riding, basketball, dancing; plan activities to discuss the food groups and their suggested serving size; provide positive feedback to the patient.
Goals are met as evidenced by:
- Patient identified feelings of perception of self.
- Patient demonstrated behaviors to restore positive self-esteem.
- Patient participated in treatment regimen to correct factors that precipitated crisis.
- Patient participated in daily physical activity 60 minutes daily.
- Patient learned how to make healthy food choices by naming the food groups.
Documentation for a child with Turner syndrome include:
- Individual findings, including factors affecting, interactions, nature of social exchanges, specifics of individual behavior.
- Intake and output.
- Cultural and religious beliefs, and expectations.
- Plan of care.
- Teaching plan.
- Responses to interventions, teaching, and actions performed.
- Attainment or progress toward the desired outcome.
Practice Quiz: Turner Syndrome
1. Somatropin (Humatrope) is being given to a female patient with Turner syndrome. Which of the following findings is associated with this medication?
1. Answer: D. Mild hyperglycemia.
- Option D: Somatropin (Humatrope) is a growth hormone. Excess growth hormone causes insulin resistance and hyperglycemia.
- Option A: Hypertension, not hypotension is a side effect.
- Option B: Water intoxication is not related symptom to this medication.
- Option C: Elevated AST and ALT is expected.
2. While Andres is being assessed at the clinic, Nurse Shiela observed that the child appears to be small, with an immature face and chubby body build. Her parents stated that their child’s rate of growth of all body parts is somewhat slow, but her proportions and intelligence remain normal. As a knowledgeable nurse, you know that the child has a deficiency of which of the following?
A. Growth hormone (GH)
B. Antidiuretic hormone (ADH)
C. Parathyroid hormone (PTH)
D. Melanocyte-stimulating hormone (MSH)
2. Answer: A. Growth hormone (GH).
- Option A: GH stimulates protein anabolism, promoting bone and soft-tissue growth. A lack of GH would lead to the decreased synthesis of somatomedin, resulting in decreased linear growth and decreased fat catabolism and increased glucose uptake in muscles, resulting in excessive subcutaneous fat hypoglycemia.
- Option B: A deficiency in ADH results in diabetes insipidus, marked by dehydration and hypernatremia.
- Option C: Deficiency of PTH causes hypocalcemia, marked by tetany, convulsions, and muscle spasms.
- Option D: Deficiency of MSH causes diminished or absent skin pigmentation.
3. In growing children, growth hormone deficiency results in short stature and very slow growth rates. Short stature may result from which of the following?
A. Posterior pituitary gland hyperfunction
B. Anterior pituitary gland hypofunction
C. Thyroid gland hyperfunction
D. Parathyroid gland hyperfunction
3. Answer: B. Anterior pituitary gland hypofunction.
- Option B: Short stature usually results from diminished or deficient growth hormone, which is released from the anterior pituitary gland.
- Option A: Posterior pituitary hyperfunction results in increased secretion of antidiuretic hormone or oxytocin, leading to a syndrome of inappropriate antidiuretic hormone secretion, marked by fluid retention and hyponatremia.
- Option D: Parathyroid hypofunction leads to hypocalcemia
- Option C: Thyroid hyperfunction causes increased secretion of thyroxine, triiodothyronine, and thyrocalcitonin, resulting in Graves’ disease, marked by accelerated linear growth and early epiphyseal closure.
4. Mr. Lopez has a 7-year-old son with Turner syndrome. He shares to the nurse the desire of his son to play ball games. However, his wife feels the child will be in danger since he is smaller than the other children. In planning anticipatory guidance for these parents, the nurse should keep in mind which of the following?
A. Activity could aggravate insulin sensitivity, causing hyperglycemia.
B. Activity would aggravate the child’s joints, already over tasked by obesity.
C. The child should be allowed to play because doing so can foster healthy self-esteem.
D. The risk for fractures is increased because a GH deficiency results in fragile bones.
4. Answer: C. The child should be allowed to play because doing so can foster healthy self-esteem.
- Option C: Engaging in peer-group activities can aid foster a sense of belonging and a positive self-concept. T-ball is a good sport to choose because physical stature is not an important consideration in the ability to participate, unlike some other sports, such as basketball and football.
- Option A: Although rare, physical activity without adequate carbohydrate intake can cause hypoglycemia.
- Option B: Moderate physical activity increases caloric use and reduces weight without undue strain on weight-bearing joints.
- Option D: Hypopituitarism does not affect calcium and phosphorus homeostasis and demineralization of bone. So the risk for fractures is not increased.
5. Ruby is receiving thyroid replacement therapy develops the flu and forgets to take her thyroid replacement medicine. The nurse understands that skipping this medication will put the client at risk for developing which of the following life-threatening complications?
A. Thyroid storm
C. Tibial myxedema
D. Myxedema coma
5. Answer: D. Myxedema coma.
- Option D: Myxedema coma, severe hypothyroidism, is a life-threatening condition that may develop if thyroid replacement medication isn’t taken.
- Option A: Thyroid storm is life-threatening but is caused by severe hyperthyroidism.
- Option B: Exophthalmos, protrusion of the eyeballs, is seen with hyperthyroidism.
- Option C: Tibial myxedema, peripheral mucinous edema involving the lower leg, is associated with hypothyroidism but isn’t life-threatening.