Growth Hormone and GnRH Agonist in Adolescents With Acquired Hypothyroidism

Hypothyroidism is often associated with growth failure. It takes several years for slow
growth to be noticed. This growth retardation is typically severe and progressive.

Thyroid hormone is necessary for normal growth. Treatment with thyroxine (thyroid hormone)
results in rapid catch-up growth, which mostly happens during the first 18 months. Growth is
accompanied by increased bone age, which means early fusion (closure of the growing bones)
of the bones and reduced growth potential. For example, a patient, who is 10 years old but
has bone age of 12 years, has growth potential of a 12 year old and will stop growing 2
years earlier than a 10 year old patient. According to the literature, prolonged juvenile
hypothyroidism (low thyroid condition) resulted in a permanent loss in height and only 70%
catch-up growth was generally achieved with thyroxine replacement.

Inclusion Criteria:

1. Patients should have clinical and biochemical evidence of hypothyroidism, T4 less
than 5.0 ng /dl , fT4 less than 1.0 mcg/dl and TSH of more than 10. Patients with
prolonged hypothyroidism should have growth failure and delayed bone age of at least
2 SD from the mean. Patients with short term hypothyroidism should have normal growth
velocity and bone age.

2. Females 8 to 16 years old.

3. Males 9 to 17 years old.

4. Patients without any chronic medical conditions.

5. Availability of a parent or guardian to attend study visits with the patient and to
be actively involved in the patient treatment plan.

6. Give written informed consent prior to any study specific screening procedure with
the understanding that the patient has the right to withdraw from the study at any
time without penalty.

Exclusion Criteria:

1. Taking medications that affect their growth. (eg. Systemic corticosteroids, anabolic
steroids)

2. Experiencing other health problems/conditions that affect their growth rate such as
growth hormone deficiency, Cushing Syndrome, rickets, and chronic diseases.

3. Patients with any condition that is a contraindication for GH therapy would include
conditions such as an active tumor, impaired glucose tolerance, neurofibromatosis
(worsening of neurofibromatosis), and hypertrophy of tonsils and adenoids with sleep
apnea. Contraindications for patients for GNRHa therapy would include a severe
systemic reaction to GNRHa which is rare, osteopenia, and osteoporosis, because
delaying puberty will worsen the condition.

4. Moving to a location that the patient will not be able to be followed by a pediatric
endocrinologist.

5. Patient is not willing to continue with the study. -