Endocrine 3 Flashcards
What does Hypothyroidism result from?
Results from a functional failure of the thyroid gland and its inability to meet the body’s demands for Thyroxine (T4) and Triidiothyronine (T3)
What are the 4 most important causes of hypothyroidism
- Developmental defects (congenital thyroid aplasia)
- Inflammation of the thyroid (Hashimotos)
- Thyroidectomy
- Iodine deficiency
Congenital thyroid aplasia (no development of the thyroid) is found in ____ in ______ newborns
1 in 4000 newborns
Inflammation of the thyroid is most often ______-mediated and includes several disorders such as Hashimoto Thyroiditis
immune-mediated
What is Hashimoto Thyroiditis characterized by?
gradual failure because of an immune destruction of the thyroid gland.
Is Hashimoto thyroidits more common in men or women and what ages is it most prevalent between?
More common in Women
most prevalent b/w 45 and 65 y/o
Which disorder causes a painless, diffuse, enlargement of the thyroid.
Hashimoto Thyroiditis
**Patients with Hashimoto Thyroidits are at an increased risk for the development of what?
**B-cell Lymphomas (30-40x)
(this will be a question)
Which disorder?
Histologically, there is extensive infiltration of the follicles and stroma with mononuclear infiltration including lymphocytes, and plasma cells which destroy the thyroid follicles and well-developed germinal centers
Subsequent healing and fibrosis may actually reduce the size
Hashimoto Thyroiditis
Which of the main causes of hypothyroidism causes an iatrogenic hypothyroidism, usually for removal of a tumor of the thyroid.
Thyroidectomy
Which of the 4 main causes of hypothyroidism is rare in western countries due to iodine being preventively added to the salt
Iodine deficiency
Occurs if the food or water does not contain adequate amounts of Iodine so hypothyroidism may occur.
The deficiency of iodine in food or water is usually associated with ________ of the thyroid gland (goiter).
nodular enlargement
Which state in the US had an increased prevalence of thyroid goiters before iodized salt?
Michigan (b/c it is surrounded by fresh water)
What happens to the follicles in iodine deficiency because the thyroid can’t synthesize enough T3 and T4? Why does it do this?
follicles undergo compensatory hyperplasia in an attempt to increase the production of hormones.
What disorder is this and what is it due to?
Goiter due to iodine deficiency
What would thyroid labs of a person with iodine deficiency look like?
Elevated TSH,
Low T3/T4 (b/c you have to have iodine and tyrosine to make active T3/T4)
Iodine deficiency- what do low concentrations of T3 and T4 in the serum result in?
- results in inadequate feedback inhibition of the pituitary, which responds to the low levels of thyroid hormones by overproducing TSH.
- TSH stimulation without adequate supplies of iodine further promotes the enlargement of the thyroid, but cannot correct the hormone deficiency.
The sxs of hypothyroidism depend on what?
The age of the patient
what do sxs of hypothyroidism look like in children?
The deficiency affects:
- growth of the entire body (dwarfism)
- the development of the CNS- mental development is retarded (cretinism)
What 2 things does hypothyroidism in a child cause if the thyroid deficiency is not recognized?
- Dwarfism
- Cretinism (mental development is retarded)
Hypo or hyperthyroidism?
- Myxedema
- Slows down function of organs
- Sleepy
- Lacks mental alertness
- Tires easily
- Lacks endurance
Hypothyroidism in adults
What is the name of the following physical exam finding and what condition is it found in?
Name: Myxedema (skin is edematous, dough-like and puffy)
seen in hypothyroidism in adults
Hyper or hypothyroidism?
- Slows down organs:
- bradycardia
- Constipation (intestines lose motility)
- skeletal muscles are weak, stiff and ache.
Hypothyroidism
What is the diagnosis of hypothyroidism based on?
biochemical measurements of thyroid hormones in the circulation
low T3/T4
elevated TSH
