January 1978 The Journal o f P E D I A T R I C S

55

Precocious puberty in juvenile hypothyroidism Three children, two girls and one boy, presented with hypothyroidism and precocious sexual development. Serum T S H and P R L were elevated in all cases. In the male patient, pituitary stimulation with T R H produced exaggerated T S H and P R L responses. Elevated serum LH, FSH, estrone, estradiol, and an attenuated gonadotropin response to GnRH were documented in the male patient and in one o f the female patients. Serum testosterone was elevated for age in one o f the female patients but prepubertal in the male patient. After treatment with L-thyroxine, elevated hormonal levels decreased to normal in one patient who returned for follow-up, Evidence is presented that precocious puberty in juvenile hypothyroidism may be the result of P R L hypersecretion.

Zuhayr S. Hemady, M.D.,* Boston, Mass., Theresa M. Siler-Khodr, Ph.D., San Antonio, Texas, and Samir Najjar, M.D., Charlottesville, Va.

PRECOCIOUS PUBERTY is a known, albeit unusual, manifestation of juvenile hypothyroidism. In 1905, Kendle 1 was the first to draw attention to this entity and as late as 1972, only 22 similar instances had been recorded? Recently, Barnes and associates, 3 after reviewing the Mayo Clinic cases, concluded that precocious sexuality is a c o m m o n feature of severe juvenile hypothyroidism provided bone age is taken as the true index of maturation. The pathogenesis of this association remains a matter of controversy and m a n y unanswered questions await further understanding of the complex endocrine interactions involved. It is the purpose of this report to describe three cases of juvenile hypothyroidism with sexual precocity. The implications of the clinical and laboratory findings to the underlying pathophysiology are discussed. CASE REPORTS Case 1. Patient L. A. K., a 3-year-old Pakistani girl, was admitted to the American University Hospital because of vaginal bleeding of 6 months duration. Since birth she was noted to be From the Departments o f Pediatrics and Obstetrics and Gynecology, American University o f Beirut Medical Center. *Reprint address: Division of Endocrinology, The Children's Hospital Medical Center, 300 Longwood Ave., Boston, MA 02115.

slow and apathetic. Growth and development were severely delayed and she could only say single words. She had chronic constipation. Eleven months prior to admission the parents noted enlargement of the breasts and growth of some pubic hair. A physician diagnosed hypothyroidism and prescribed a thyroid preparation which she received for 12 days only. Six months prior to admission she had an episode of profuse vaginal bleeding which continued for five days. Thereafter several episodes of vaginal bleeding were noted. On physical examination the patient had a typical hypothyroid facies, dry skin, and a hoarse Abbreviations used TSH: thyroid-stimulating hormone PRL: prolactin LH: luteinizing hormone FSH: follicle-stimulating hormone El: estrone E2: estradiol A: androstenedione T: testosterone T4: thyroxine TRH: thyrotropin-releasing hormone GnRH: gonadotropin-releasing hormone GH: growth hormone ACTH: adrenocorticotropic hormone voice. Height was 78 cm (height age 14/12years) and weight was 10.5 kg. The head circumference was 45 cm. She had no goiter. Breast tissue was definitely palpable bilaterally, and milk was expressed upon pressure. The abdomen was soft and two nontender cystic movable masses could be felt in the lower

Vol. 92, No. 1, pp. 55-59

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Hemady, Siler-Khodr, and Najjar

The Journal of Pediatrics January 1978

Table I. Serum h o r m o n a l c o n c e n t r a t i o n s before a n d after t r e a t m e n t of three h y p o t h y r o i d children

Patients S.S. L. A.K. A.D. A.D.

Therapy None None None 200 ~g L-thyroxine for 2 mo

T4 TSH (l~g/dl) I(l~U/ml)I

PRL (ng/ml)

1.8 2.8 2.3 6.2

540 2,050 620 10

53 250 74 26

Normal adults

4-12

Precocious puberty in juvenile hypothyroidism.

January 1978 The Journal o f P E D I A T R I C S 55 Precocious puberty in juvenile hypothyroidism Three children, two girls and one boy, presented w...
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