Flashcards in Ch 21: Endocrine- Thyroid Deck (19)
You open a practice in Ithaca and your first patient comes in with an enlarged neck mass. She says she doesn't understand why she isn't healthy, as she eats only natural, unfortified products and is strictly vegan. Her mass is her only complaint, as she feels fine otherwise.
You draw blood and find an elevated TSH but normal thyroid hormones. What does she have and how might she have gotten it?
Thyroid enlargement without functional problems (sometimes elevated TSH but it doesn't have to be)
Was going for a lack of iodine causing endemic goiter if she doesn't use iodized salt or eat seafood, however, even then she probably would get enough iodine from some veggies.
Can also be caused by sulfonamides, excess iodine, or genetic causes.
What is myxedema and what conditions is it seen in?
Proteoglycan accumulation in ECM binds water forming edema.
Seen in hypothyroidism and also Graves (where is causes pretibial myxedema)
What are some symptoms of HYPOthyroidism?
Fatigue, sensitivity to cold, puffy eyelids, peripheral edema, enlarged tongue, reduced HR and SV, decreased peristalsis, anovulatory cycles
A 3-wk old baby is taken to your office because of failure to thrive. He doesn't move around a lot, and is anemic. You narrow the differential down to an endocrine disorder. What does he have?
If this is not due to diet, what else can cause it?
If you don't fix it, what will develop?
Cretinism aka congential hypothyroidism
Developmental defect of the thyroid (agenesis or dysgenesis)
Can progress to mental retardation, dwarfism, ataxia, and deaf-mutism if not corrected
A 56 y/o woman comes in with complaints that her hair is becoming more fine, she's sweating all the time, and becoming easily agitated. Although her husband thinks its just menopause, you order a TSH and thyroid antibody tests.
What do you find?
Low TSH, IgG antibodies that are agonists for the TSH receptor, increasing thyroid hormone secretion.
Caused by B cells that are auto reactive to TSH receptors
What other cells might have TSH receptors, and what characteristic sign of Graves disease might result?
Orbital fibroblasts might have TSH receptors. T lymphocytes accumulate around the eye, secrete cytokines which activate fibroblasts, which proliferate and produce collagen and GAGs.
This accumulation of fibroblasts, lymphocytes, and edema can produce exophthalmos
Histologically, what cancer can a Graves' thyroid be confused with? How do you tell the difference?
Hyperplasia of papilla can be misdiagnosed as papillary carcinoma
Graves has hyperchromatic nuclei, carcinoma has clear nuclei.
Your 70 y/o pt comes in with congestive heart failure. Her PMH is notable for a history of nontoxic multi nodular goiter. What has happen to her thyroid, and what does she now have?
Toxic multinodular goiter
Essentially her thyroid has gone rogue and became autonomous, hyper functioning nodules
In older people, cardiac complications and common
What is the mechanism for Hashimoto's thyroiditis?
Autoreactive B cells secrete anti-thyrocyte antibodies, and CD8 T cells make cytotoxic T cells to thyrocytes. This leads to eventual thyrocyte death
Causes an enlarged thyroid gland, and either hyper or hypothyroidism, usually progressing to hypothyroidism if untreated
How is Hashimoto's detected and what would it look like histologically?
Detected by presence of circulating anti-thryoid antibodies, low T4 and elevated TSH.
Thyroid infiltrated by lymphocytes and plasma cells
A 40 y/o woman comes in complaining of neck pain. She said she had a cold a few weeks ago, but then developed hoarseness and this pain.
What does she have and what would the thyroid look like?
Subacute or de Quervain thyroiditis
Lymphocytes infiltrate gland, releasing colloid, which gets destroyed and sequestered in a GRANULOMATOUS reaction.
What is Riedel thyroiditis and what unusual presentation does it have?
Thyroid turns hard and "woody" due to fibrosis, which can extend into other soft tissues of the neck. Chronic inflammation also accompanies the fibrosis. It can compress other neck organs
A nodule that protrudes from the thyroid and is COMPLETELY surround by a thin fibrous CAPSULE is what?
Follicular adenoma of thyroid
(Caps are to emphasize the non-invasive nature, which distinguishes it from a follicular carcinoma)
What is the most common type of thyroid cancer and what is a major risk factor for it?
What proto-oncogene is often mutated?
Papillary thyroid carcinoma
What are there distinct histological features of papillary thyroid carcinoma?
Orphan Annie nuclei (clear, like the cartoon characters's eyes)
Psammoma bodies (concentric calcifications)
What cancer commonly has a thick, fibrous capsule which it commonly invades?
How does this type of cancer metastasize?
Follicular thyroid carcinoma
Hematogenously because it invades blood vessels
Medullary thyroid carcinoma comes from what type of cells of the thyroid?
If amyloid develops, what is it usually derived from?
What endocrine syndrome is commonly associated with medullary thyroid carcinoma?
MEN2A or B. Can be due to a RET mutation.
People with MEN2A/B who are at risk have calcitonin monitored to watch out for C cell hyperplasia, and can get a preventive thyroidectomy to avoid MTC.