Turner Syndrome and Diabetes
Turner Syndrome and Diabetes
I am treating a 4-year-old with Turner syndrome and type 1 diabetes. She has no malformations, her height is 92 cm, and her metabolic control is excellent (HbA1c, 6%). Her parents have been informed about her ultimate height prognosis, and they are requesting that she be treated with growth hormone. I am reluctant because of the side effects on glycemia, and am concerned about how growth hormone treatment might be managed in such a patient. What are your thoughts?
The use of growth hormone (GH) in your patient presents a significant dilemma. Unfortunately, there is no "right" answer. However, an objective assessment of the risks and benefits of GH therapy can help identify the best option available for your patient. Fortunately, your patient's clinical status can be reassessed periodically to determine whether the course of action taken should be reconsidered or modified.
The assessment of the risks and benefits of GH treatment should take into consideration the following: Despite the variability in the clinical stigmata of girls with Turner syndrome, most individuals with the condition will invariably have short stature and gonadal insufficiency. The average adult height of subjects with Turner syndrome is about 143 cm, or approximately 4'8". In order to optimize final adult height, treatment with estrogen has often been delayed until late in adolescence.
Treatment with GH can improve the adult heights of girls with Turner syndrome; the average final adult height of girls treated with GH is about 59'' to 60". Early initiation of GH treatment allows for the more adequate timing of estrogen replacement therapy in girls with Turner syndrome.
Individuals with Turner syndrome are more likely to develop diabetes mellitus, but the incidence is not increased by treatment with GH. Nevertheless, GH is diabetogenic; prolonged GH therapy results in insulin resistance and hyperglycemia in normal subjects, and lipolysis and ketosis in individuals with diabetes. The clinical response to GH treatment is extremely variable and difficult to predict; some Turner girls respond better to GH treatment than others.
In general, I believe that the potential benefits of GH therapy outweigh the potential risks of GH treatment in girls with Turner syndrome and diabetes. However, I usually discuss the potential risks and benefits of treatment objectively with patients and their parents, giving them the opportunity of having all of their questions answered. I also make it clear that GH treatment is not a "magic bullet" and that careful monitoring will be required to make sure that treatment is effective and well tolerated. I use a written "informed consent" in some cases to inform the patient and her parents of the potential risks and benefits while documenting their assent and/or consent to treatment, as appropriate.
I typically advise my patients with Turner syndrome and diabetes that GH treatment be provided daily and started at lower than recommended doses. I usually start at a dose of 0.125 mg/kg/week and increase the dose every 2 or 3 weeks by 0.125 mg/kg/week, up to a maximum dose of 0.375 mg/kg/week. I advise patients and their parents that blood glucose and glycosylated hemoglobin levels be followed closely so that insulin doses can be adjusted as needed. Regular follow-up at 1 month after starting treatment and quarterly thereafter typically allows for adequate monitoring of the safety and efficacy of treatment.
I am treating a 4-year-old with Turner syndrome and type 1 diabetes. She has no malformations, her height is 92 cm, and her metabolic control is excellent (HbA1c, 6%). Her parents have been informed about her ultimate height prognosis, and they are requesting that she be treated with growth hormone. I am reluctant because of the side effects on glycemia, and am concerned about how growth hormone treatment might be managed in such a patient. What are your thoughts?
The use of growth hormone (GH) in your patient presents a significant dilemma. Unfortunately, there is no "right" answer. However, an objective assessment of the risks and benefits of GH therapy can help identify the best option available for your patient. Fortunately, your patient's clinical status can be reassessed periodically to determine whether the course of action taken should be reconsidered or modified.
The assessment of the risks and benefits of GH treatment should take into consideration the following: Despite the variability in the clinical stigmata of girls with Turner syndrome, most individuals with the condition will invariably have short stature and gonadal insufficiency. The average adult height of subjects with Turner syndrome is about 143 cm, or approximately 4'8". In order to optimize final adult height, treatment with estrogen has often been delayed until late in adolescence.
Treatment with GH can improve the adult heights of girls with Turner syndrome; the average final adult height of girls treated with GH is about 59'' to 60". Early initiation of GH treatment allows for the more adequate timing of estrogen replacement therapy in girls with Turner syndrome.
Individuals with Turner syndrome are more likely to develop diabetes mellitus, but the incidence is not increased by treatment with GH. Nevertheless, GH is diabetogenic; prolonged GH therapy results in insulin resistance and hyperglycemia in normal subjects, and lipolysis and ketosis in individuals with diabetes. The clinical response to GH treatment is extremely variable and difficult to predict; some Turner girls respond better to GH treatment than others.
In general, I believe that the potential benefits of GH therapy outweigh the potential risks of GH treatment in girls with Turner syndrome and diabetes. However, I usually discuss the potential risks and benefits of treatment objectively with patients and their parents, giving them the opportunity of having all of their questions answered. I also make it clear that GH treatment is not a "magic bullet" and that careful monitoring will be required to make sure that treatment is effective and well tolerated. I use a written "informed consent" in some cases to inform the patient and her parents of the potential risks and benefits while documenting their assent and/or consent to treatment, as appropriate.
I typically advise my patients with Turner syndrome and diabetes that GH treatment be provided daily and started at lower than recommended doses. I usually start at a dose of 0.125 mg/kg/week and increase the dose every 2 or 3 weeks by 0.125 mg/kg/week, up to a maximum dose of 0.375 mg/kg/week. I advise patients and their parents that blood glucose and glycosylated hemoglobin levels be followed closely so that insulin doses can be adjusted as needed. Regular follow-up at 1 month after starting treatment and quarterly thereafter typically allows for adequate monitoring of the safety and efficacy of treatment.