Can you have a pituitary tumor with normal TSH levels?
Can you have a pituitary tumor with normal TSH levels?
A diagnosis is confirmed by: Blood tests: In general, elevated T3 and/or T4 in the presence of normal or elevated TSH suggests a TSH-producing tumor. In some cases, thyroid hormones are normal despite the presence of a tumor. This is called a silent TSH adenoma.
What is the abnormal range of TSH?
TSH normal values are 0.5 to 5.0 mIU/L. Pregnancy, a history of thyroid cancer, history of pituitary gland disease, and older age are some situations when TSH is optimally maintained in different range as guided by an endocrinologist. FT4 normal values are 0.7 to 1.9ng/dL.
What is TRH secreting tumor?
TSH-secreting (thyrotroph) adenomas are tumors of the pituitary gland that secrete thyroid-stimulating hormone (TSH), which causes excess production of thyroid hormones (T3 and T4) by the the thyroid gland – a condition known as hyperthyroidism.
Can pituitary adenoma cause hypothyroidism?
Primary hypothyroidism is characterized by loss of thyroxine feedback inhibition and overproduction of thyrotropin releasing hormone (TRH), which might result in reactive pituitary hyperplasia. However, pituitary adenoma secondary to primary hypothyroidism is extremely rare and usually underdiagnosed.
What is TSH secreting pituitary adenoma?
TSH-secreting pituitary adenomas are benign tumours of the pituitary gland. They produce too much thyroid stimulating hormone (TSH), which causes the thyroid gland to enlarge and produce thyroid hormone in excess, leading to an overactive thyroid (hyperthyroidism).
Can TSH be low in hypothyroidism?
The finding of an elevated TSH and low FT4 or FTI indicates primary hypothyroidism due to disease in the thyroid gland. A low TSH and low FT4 or FTI indicates hypothyroidism due to a problem involving the pituitary gland.
What is the prevalence of TSH adenoma?
Thyroid-stimulating hormone (TSH)-secreting pituitary adenomas are a rare cause of hyperthyroidism [1]. They account for 0.5 to 3 percent of all functioning pituitary tumors [2] and much less than 1 percent of all cases of hyperthyroidism.
What is the normal range for TSH levels?
The biological activity of the TSH that is secreted varies considerably; as a result, serum immunoreactive TSH concentrations range from normal (albeit inappropriately high in the presence of hyperthyroidism) to markedly elevated (>500 mU/L) [ 3 ]. Most TSH-secreting adenomas secrete only TSH.
Do TSH-secreting adenomas secrete other hormones?
Most TSH-secreting adenomas secrete only TSH. However, approximately 20 to 25 percent of the adenomas secrete one or more other pituitary hormones, predominantly growth hormone or prolactin [ 2 ]. There have been no reported instances of cosecretion of corticotropin (ACTH) and TSH.
What does it mean when your TSH and T4 are elevated?
Elevated T4 and T3 levels combined with elevated or normal TSH levels can also be a sign of central resistance to thyroid hormone. Central or pituitary resistance to thyroid hormone is a genetic disorder caused by a mutation in the T3 receptor in cells of the pituitary gland.
