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October 1988

Marked Hyperprolactinemia in Subclinical Hypothyroidism

Author Affiliations


From the Departments of Medicine, US Air Force Medical Center, Wright-Patterson Air Force Base, Ohio, and Wright State University School of Medicine, Dayton, Ohio.

Arch Intern Med. 1988;148(10):2278-2279. doi:10.1001/archinte.1988.00380100122027

• Hyperprolactinemia is common in primary hypothyroidism but, to our knowledge, marked elevation of serum prolactin in subclinical hypothyroidism has not been previously reported. A 45-year-old woman presenting with carpal tunnel syndrome was found to have a minimally elevated level of thyrotropin with a normal level of thyroxine. Thyrotropin releasing hormone stimulation testing revealed hyperresponsiveness consistent with primary hypothyroidism. An unstimulated prolactin level was 187 μg/L and returned to normal with levothyroxine therapy. Results of visual field testing were normal, and a computed tomographic scan of the pituitary gland revealed no evidence of a macroadenoma. This case demonstrates the occurrence of significant hyperprolactinemia in the absence of overt primary hypothyroidism.

(Arch Intern Med 1988;148:2278-2279)

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