by Michael Lionetti 7 years ago
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Accounts for 60,220 cases a year with 1850 deaths
Ionizing radiation is most consistent causal factor
Present in 1 of every 3 to 4 thousand births
Hereditary defects in TH synthesis
Absent thyroid tissue
Mild thyroid failure
Is an elevation in TSH level with normal levels of TH
Pituitary or hypothalamic failure with failure to stimulate normal thyroid function
Caused by pituitary tumors that compress surround pituitary cells
Also caused by treatment of theses tumors
Traumatic brain injury
Subarachnoid Hemorrhage
Pituitary infarction
Inadequate amounts of TSH or lack of TRH
Lack of negative feedback to hypothalamic release of TRH by TSH and TH
Low levels of TSH and TH and high levels of TRH
Treatment of other symptpoms
Levothyroxine
Pituitary or thyroid gland
Low levels of TH and high levels of TSH and TRH
Endemic iodine deficiency
Most common cause worldwide
Rare in U.S due to iodized salt and fortified foods
Endemic goiter
Medications
Head and neck radiation therapy
Iatrogenic loss of thyroid tissue after surgical or radioactive treatment for hyperthroidism
Autoimmune thyroiditis (Hashimoto disease)
Most common cause in United States
Due to genetic disposition
associated with
IFN-A
chronic hepatitis C
smoking
Selenium deficinecy
High iodine intake
Gradual inflammatory destruction of thyroid tissue due to infiltration of
Induction of apoptosis
Antibody activation of natural killer cells
Auto reactive T lympocytes
Circulating thyroid autoantibodies
Lymphocytes