Hyperprolactinemia in patients with high TSH levels with both clinical and subclinical hypothyroidism

Abstract

Hyperprolactinemia is the most common endocrine disorder involving hypothalamic–pituitary axis. This results from multiple causes such as medications, hypothyroidism, and pituitary disorders. Hyperprolactinemia and hypothyroidism are closely interrelated conditions. The present study aimed to estimate serum prolactin levels and determine the prevalence of hyperprolactinemia in newly diagnosed subclinical and clinical hypothyroid patients and correlation between TSH and prolactin levels in subclinical and clinical hypothyroid patients.This study was conducted in the Department of Biochemistry, in collaboration with Department of Medicine, Department of Obstetrics and Gynecology, LATE BRKM Government Medical College, Jagdalpur, Chhattisgarh, India. Total of 138 patients presenting to Department of Medicine for various thyroid related problems were involved in this study. The newly diagnosed cases of primary hypothyroidism were included in this study. The demographic, physical and clinical history was taken from all the study subjects. In the present study, serum prolactin levels were significantly increased in subclinical (28.7 ± 6.4 ng/mL) and clinical hypothyroidism (15.02 ± 4.2ng/mL) compared to controls. Hyperprolactinemia was observed in 11 (22.9%) patients in subclinical hypothyroidism and 4 (8.3%) in clinical hypothyroid patients. In the subclinical hypothyroidism and clinical hypothyroidism, the serum TSH levels were (17.01 ± 8.2 μU/l, 7.3 ± 2.0 μU/l respectively) significantly increased than the controls. In the clinical hypothyroidism and subclinical hypothyroidism, the serum free T3 (fT3) levels were (5.6 ± 0.68 pmol/l, 2.54 ± 0.43 pmol/l respectively) significantly increased than the controls. In the clinical hypothyroidism and subclinical hypothyroidism, the serum total T3 (T3) levels were (1.27± 0.24 nmol/l, 0.59±0.12 nmol/l respectively) significantly increased than the controls. The study results may conclude that, prolactin regulation is altered, in patients with clinical and subclinical hypothyroidism. Thyroid functions tests ought to be conducted in patients with hyperprolactinemia prior to performing further tests.