Hypothyroidism can cause irregular menstrual bleeding, hair loss, and lactation in a teenage girl that has never been sexually active. I recommend that the teenage girl be examined and treated for hypothyroidism by a pediatric endocrinologist.
Galactorrhea ("lactation") is when a woman's breast makes milk even though she is not breastfeeding a baby. Galactorrhea develops in hypothyroidism secondary to Thyroid Releasing Hormone secretion from the hypothalamus. Thyroid Releasing Hormone stimulates the anterior pituitary to release Thyroid Stimulating Hormone and prolactin which stimulates the mammary glands to produce milk (lactation). A hypothyroid adolescent girl's galactorrhea will resolve as her prolactin concentrations fall after she is treated with thyroid hormone replacement.
A serum TSH (serum thyrotropin stimulating hormone) test is the most sensitive screening test for diagnosing primary hypothyroidism, although a value within the reference range does not exclude TSH deficiency or TRH deficiency. Serum TSH level is a guide to the dose of thyroid hormone replacement except in patients with secondary hypothyroidism where serum free T4 is diagnostic. Adequate thyroid hormone replacement results in normalization of serum TSH.
Approximately 10% of adolescent females have some signs of autoimmune thyroid disease, usually chronic lymphocytic thyroiditis. Chronic lymphocytic thyroiditis usually presents during adolescence. Frequently adolescent girls with hypothyroidism suffer from menstrual irregularity and galactorrhea. Approximately 20% of them recover to a normal thyroid state and do not require lifelong thyroid hormone replacement. After treatment beyond the completion of puberty, a 6-month trial off of thyroid hormone replacement therapy should be considered with monitoring of serum TSH and total T4 levels every 3 months. If serum TSH levels rise above the reference range then the levothyroxine treatment should be resumed and continued for life. Patients with chronic lymphocytic thyroiditis should have a yearly serum total T4 and TSH to assure adequate treatment and maintenance of a normal thyroid.
Edited by DrHanson on September 22 2006 at 5:33pm
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