Endo - Pathology (Thyroid) Flashcards
Pg. 320-323 in First Aid 2014 Sections include: -Hypothyroidism vs. hyperthyroidism -Hypothyroidism -Hyperthyroidism -Thyroid cancer
Compare/Contrast hypothyroidism and hyperthyroidism in terms of their 8 major sets of symptoms.
(1) HYPO: Cold intolerance (decreased heat production), HYPER: Heat intolerance (increased heat production) (2) HYPO: Weight gain, decreased appetite, HYPER: Weight loss, increased appetite (3) HYPO: Hypoactivity, lethargy, fatigue, weakness, HYPER: Hyperactivity (4) HYPO: Constipation, HYPER: Diarrhea (5) HYPO: Decreased reflexes, HYPER: Increased reflexes (6) HYPO: Myxedema (facial/periorbital), HYPER: Pretibial myxedema (Graves disease), Periorbital edema (7) HYPO: Dry, cool skin; coarse brittle hair, HYPER: Warm, moist skin; fine hair (8) HYPO: Bradycardia, dyspnea on exertion, HYPER: Chest pain, palpitations, arrhythmias, increased number and sensitivity of Beta-adrenergic receptors
What are the following lab findings in hypothyroidism versus hyperthyroidism: (1) TSH (2) free T3 and T4 (3) Cholesterol?
(1) HYPO: High TSH (sensitive test for primary hypothyroidism), HYPER: Low TSH (if primary) (2) HYPO: low free T3 and T4, HYPER: High free or total T3 and T4 (3) HYPO: Hypercholesterolemia (due to low LDL receptor expression), HYPER: Hypocholesterolemia (due to high LDL receptor expression)
What is the most common cause of hypothyroidism in idodine-sufficient regions?
Hashimoto thyroiditis
What is Hashimoto thyroiditis, and what is its mechanism of damage?
An autoimmune disorder (anti-thyroid peroxidase, antithyroglobulin antibodies)
With what HLA type is Hashimoto thyroiditis associated?
Associated with HLA-DR5
For what condition does Hashimoto thyroiditis increase the risk?
Increased risk of non-Hodgkin lymphoma
When might Hashimoto thyroiditis patients be hyperthyroid, and why?
May be hyperthyroid early in course due to thyrotoxicosis during follicular rupture
What are 2 major histologic findings in Hashimoto thyroiditis?
Histologic findings: Hurthle cells, lymphoid aggregate with germinal centers
Describe the thyroid upon physical exam in a Hashimoto thyroiditis patient.
Findings: moderately enlarged, NONTENDER thyroid
What are 8 conditions/causes of hypothyroidism?
(1) Hashimoto thyroiditis (2) Congenital hypothyroidism (Cretinism) (3) Subacute thyroiditis (de Quervain) (4) Riedel thyroiditis (5) Iodine deficiency (6) Goitrogens (7) Wolff-Chaikoff effect (8) Painless thyroiditis
What is another name for Congenital hypothyroidism? What is it, and what causes it?
Congenital hypothyroidism (Cretinism); Severe fetal hypothyroidism due to maternal hypothyroidsim, thyroid agenesis, thyroid dysgenesis (most common cause in US), iodine deficiency, dyshormonogenic goiter
What are 6 physical exam/clinical findings of Congenital hypothyroidism (Cretinism)?
Findings: (1) Pot-bellied (2) Pale (3) Puffy-faced child with (4) Protruding umbilicus (5) Protuberant tongue and (6) Poor brain development; Think: “the 6 P’s”
In the US, what is the most common cause of Congenital hypothyroidism (Cretinism)?
Thyroid dysgenesis (most common cause in US)
What is another name for Subacute thyroiditis? What is it, and what condition does it often folow?
Subacute thyroiditis (de Quervain); Self-limited hypothyroidism often following a flu-like illness
What does Subacute thyroiditis (de Quervain) have in common with Hashimoto thyroiditis in terms of its early presentation?
May be hyperthyroid early in course
What is significant in the histology of Subacute thyroiditis (de Quervain)?
Histology: granulomatous inflammation
What are 4 lab/clinical findings associated with Subacute thyroiditis (de Quervain)?
Findings: (1) high ESR (2) Jaw pain (3) Early inflammation (4) very TENDER thyroid; Think: “de querVAIN is associated with PAIN”
What is a major way that Hashimoto thyroiditis and Subacute thyroiditis differ on physical exam?
Hashimoto thyroiditis: NONTENDER thyroid; Subacute thyroiditis: very TENDER thyroid
What occurs in Riedel thyroiditis?
Thyroid replaced by fibrous tissue (hypothyroid).
To where may the fibrosis in Riedel thyroiditis extend, and what condition does that mimick?
Fibrosis may extend to local structures (e.g., airway), mimicking anaplastic carcinoma
Of what disease is Riedel thyroiditis considered to be a manifestation?
Considered a manifestation of IgG4-related systemic disease
What is the main clinical/physical exam finding in Riedel thyroiditis?
Findings: fixed, hard (rock-like, and PAINLESS goiter
What are 3 types/causes of hyperthyroidism?
(1) Toxic multinodular goiter (2) Graves disease (3) Thyroid storm
What defines toxic multinodular goiter, and what causes it?
Focal patches of hyperfunctioning follicular cells working independently of TSH due to mutation in TSH receptor
What effect does toxic multinodular goiter have on thyroid hormone levels?
Increase release of T3 and T4
Comment on the malignancy of hot nodules in Toxic multinodular goiter.
Hot nodules are rarely malignant
What is Jod-Basedow phenomenon? With what thyroid condition is it associated?
Jod-Basedow phenomenon - Thyrotoxicosis if a patient with iodine deficiency goiter is made replete; Toxic multinodular goiter
What is the most common cause of hyperthyroidism?
Graves disease
What causes/defines Graves disease, and on what 3 locations does it act? What symptoms relate to each of these locations?
Autoantibodies (IgG) stimulate (1) TSH receptors on thyroid (hyperthyroidism, diffuse goiter), (2) Retro-orbital fibroblasts (exophthalmos: proptosis, extraocular muscle swelling), and (3) Dermal fibroblasts (pretibial myxedema)
In what context does Graves disease often present? Give an example.
Often presents during stress (e.g., childbirth)
What causes a thyroid storm, and what is it?
Stress-induced catecholamine surge seen as a serious complication of Graves disease and other hyperthyroid disorders
What are 6 signs/symptoms in the presentation of thyroid storm? Which is a cause of death?
Presents with (1) agitation (2) delirium (3) fever (4) diarrhea (5) coma (6) tachyarrhythmia (cause of death).
What is a significant lab finding that may be seen in thyroid storm, and what causes it?
May see high ALP due to increased bone turnover
How is thyroid storm treated?
Treat with the “3 P’s”: beta-blockers (e.g., Propranolol), Propylthiouracil, corticosteroids (e.g., Prednisolone)
What may be seen on histology of mulitnodular goiter?
Follicles of various sizes distended with colloid and lined by flattened epithelium with areas of fibrosis and hemorrhage
Describe the physical exam finding of exophthalmos in a Graves disease patient.
Patient with bilateral proptosis and eyelid retraction. Visible sclera causes appearance of a “stare”.
What is the treatment option for thyroid cancers? What other thyroid condition can also use this treatment?
Thyroidectomy is treatment option for thyroid cancers and hyperthyroidism
What are 3 complications of thyroidectomy? Where applicable, explain the cause.
Complications of surgery include (1) hoarseness (due to recurrent laryngeal nerve damage), (2) hypocalcemia (due to removal of parathyroid glands), and transection of inferior thyroid artery
What are 5 types of thyroid cancer?
(1) Papillary carcinoma (2) Follicular carcinoma (3) Medullary carcinoma (4) Undifferentiated/Anaplastic carcinoma (5) Lymphoma
What is the most common thyroid cancer? What kind of prognosis does it have?
Papillary carcinoma; Most common, excellent prognosis
What are 3 histologic findings that characterize papillary carcinoma of the thyroid?
(1) Empty-appearing nuclei (“Orphan Annie” eyes) (2) Psammoma bodies (3) Nuclear grooves
What are 3 risk factors for papillary carcinoma of the thyroid?
Increase risk with RET and BRAF mutations, childhood irradiation
What kind of prognosis does Follicular carcinoma of the thyroid have?
Good prognosis
How is Follicular carcinoma distinguished from Follicular adenoma of the thyroid? Also, in one word, describe the follicles of Follicular carcinoma?
Invades thyroid capsule (unlike follicular adenoma), uniform follicles
What is the cellular origin of Medullary carcinoma thyroid?
From parafollicular “C cells”
What is produced by Medullary carcinoma of the thyroid?
Produces calcitonin
What histologic finding defines Medullary carcinoma of the thyroid?
Sheets of cells in an amyloid stroma
With what conditions is Medullary carcinoma of the thyroid associated, and what mutation causes these?
Associated with MEN 2A and 2B (RET mutations)
What patient population is (mostly) affected by undifferentiated/anaplastic carcinoma?
Older patients
To what extent does Undifferentiated/Anaplastic carcinoma grow? What is its prognosis?
Invades local structures, very poor prognosis
With what thyroid condition is lymphoma associated?
Associated with Hashimoto thyroiditis
