Wk5 Hypothyroidism Flashcards
Ture or False: 95% pf hypothyroid cases are due to primary hypothyroidism.
True
What is iatrogenic hypothyroidism?
Thyroid dysfunction caused by medical examination or treatment.
Does resistance to thyroid hormone commonly occur?
No, very rare.
What are the two common cause of hypothyroidism?
iodine deficiency and autoimmunity.
excessive or insufficient iodine can both lead to hypothyroidism.
What is the most common cause of hypothyroidism in North America?
Autoimmunity hypothyroidism
Under the category of autoimmunity hypothyroidism, what are the two subtype?
Hashimoto thyroiditis –most common
De Quervain disease (subacute granulomatous thyroiditis) — rare
What is the most common cause of central hypothyroidism?
Pituitary adenomas
What are the two main contributions to the symptoms of hypothyroidism?
- generalized slow metabolism
- polysaccharides accumulation in interstitial spaces
When should we refer our patient to fine-needle aspiration biopsy in the condition of goiter?
If there’s the presence of nodule
How is goiter diagnosed?
Ultrasound (assess the size and structure of the thyroid)
Under which condition, would surgery be needed on goiter?
If the enlargement causes difficulty breathing, swallowing or hoarseness.
Most goiters are euthyroid, hypothyroid or hyperthyroid?
Euthyroid (normal thyroid function)
True or False: goiter can be physiologic which is seen in adolescence and pregnancy due to increased thyroid demands.
True
Can goiter be a symptom of hyperthyroidism?
YES. In condition such as Grave’s disease, toxic nodular/multinodular goiter, thyroid cancer or infiltrative disease.
True or false: goiter can be a symptom of inflammatory disorders — autoimmune, postpartum, silent, radiation, subacute, suppurative.
True.
What is goiter due to iodine deficiency called?
Endemic goiter
Which symptom do patient experience most frequently in hypothyroidism?
Tiredness (sensitivity of 81%)
Which symptoms if present, significantly increase the likelihood of autoimmune hypothyroidism?
Anterior neck pain
Which symptom, if is absent, decrease the likelihood of autoimmune hypothyroidism?
Tiredness
As the autoimmune hypothyroidism progress, which two symptoms are relatively more common?
Drier skin & poorer memory
In progressive autoimmune hypothyroidism, which symptom, if present, significantly increase the likelihood of autoimmune hypothyroidism?
Feeling colder
True or False: When diagnosing thyroid-related symptoms, clinicians must differentiate between true thyroid dysfunction and other non-thyroidal causes that can mimic or co-exist with thyroid diseases, where TSH levels are normal but symptoms persist.
True
Can biotin interfere with laboratory testing of TSH, T4, T3?
Yes. Biotin can falsely cause high T4, high T3 and low TSH, which appear as hyperthyroidism or thyroid replacement dosing is too high.
True or False: Various non-thyroidal illnesses, medications, and external factors can lead to falsely elevated TSH or falsely low T4/T3 levels, potentially mimicking thyroid dysfunction.
Ture. These factors must be considered when interpreting thyroid function tests to avoid misdiagnosis and unnecessary treatment.
How long before thyroid function test should a patient avoid biotin supplementation?
48hr.
What does St johns wort do to thyroid function test?
Falsely elevate TSH
Low TSH should indicate hyperthyroid state or hypothyroid state?
Low TSH & high T3, T4 —> hyperthyroidism
What is central hypothyroidism? Is thyroid normal ? is pituitary or hypothalamus normal?
Central hypothyroidism is due to insufficient stimulation to the thyroid gland.
Thyroid gland is normal, problems are in the pituitary gland or the hypothalamus
What is the prevalence of central hypothyroidism?
Less than 1% of hypothyroid cases
What is the common cause of central hypothyroidism in children?
Common cause include brain tumor (craniopharyngiomas), crania irradiation…
What is the common cause of central hypothyroidism in adult?
Pituitary macroadenomas (noncancerous tumor in the pituitary), pituitary surgeries, or radiation therapy to the pituitary area.
Can over-replacement of T4 cause central hypothyroidism?
Yes. Patient with primary hypothyroidism who are receiving too much thyroid hormone replacement may develop temporary suppression of the pituitary.
Is the symptom of central hypothyroidism milder than primary hypothyroidism?
Yes. Because the lack of thyroid hormones develops slowly, allowing the body to partially adapt.