ODP529 Update on the Prevalence and Pathogenesis of Central Hypothyroidism

Abstract Background Central hypothyroidism (CH) is a rare form of hypothyroidism characterized by insufficient stimulation of a normal thyroid gland by the thyroid-stimulating hormone (TSH). It can be of pituitary origin (secondary hypothyroidism) or hypothalamic origin (tertiary hypothyroidism). The diagnosis is suspected by the finding of low serum free thyroxine associated with low, normal, or slightly elevated serum TSH, in the absence of goiter. This review presents an update on the prevalence and pathogenesis of different types of CH. Methods A systematic search of literature was conducted using the search terms hypothyroidism, central hypothyroidism, congenital central hypothyroidism, acquired central hypothyroidism, TSH deficiency, prevalence, and pathogenesis. Results The prevalence of overt hypothyroidism in the US population is at least 0.3% and the prevalence of subclinical hypothyroidism ranges from 4% to 10%. Primary hypothyroidism is more prevalent in females. The prevalence of CH ranges from 1: 13,000 to 1: 120,000. CH is observed in less than 1% of hypothyroid subjects, with no evidence of sex predominance. Itcan occur prenatally (congenital CH) or after birth (acquired CH). Congenital CH, which is a rare cause of CH (prevalence around 1: 13,000), may result from genetic/malformative causes [e. g., pituitary-specific transcription factor defects, TSH-beta subunit gene mutations, isolated TSH-releasing hormone (TRH) deficiency, TRH receptor gene mutation, immunoglobulin superfamily member 1 deficiency, De Morsier syndrome, Prader Willi syndrome]. In 60% of the cases, congenital CH is associated with other pituitary hormone deficiencies and in 40% of the cases, congenital CH is due to isolated TSH deficiency. Acquired CH, which is the most common cause of CH andusually associated with other pituitary hormone deficiencies, results from the destruction or inhibition of the pituitary and/or hypothalamus. In decreasing order of frequency, acquired CH can be secondary to invasive and/or compressive lesions (e. g., pituitary macroadenomas, craniopharyngiomas, pituitary metastases, carotid aneurysm), iatrogenic factors (e. g., surgery or irradiation, glucocorticoids, dopaminergic drugs, somatostatin analogs, immune checkpoint inhibitors), trauma (e. g., brain injury), vascular causes (e. g., pituitary apoplexy, postpartum pituitary necrosis, hemorrhage), autoimmunity (e. g., lymphocytic hypophysitis), infiltrative lesions (e. g., hemochromatosis, sarcoidosis), and infections (e. g., tuberculosis, syphilis). Conclusion CH is a rare cause of hypothyroidism resulting from a variety of congenital or acquired causes. Acquired CH is the most common cause of CH. In many cases, both congenital and acquired CH are associated with multiple pituitary hormone deficiencies. Isolated TSH deficiency is rare and usually of congenital origin. Presentation: No date and time listed