Thyroid Flashcards
essential action of the thyroid
increase basal metabolic rate
TSH stimulates the production of…
Thyroglobulin (TG)
*iodide is incorporated with TG before being cleaved into T3 and T4
causes of primary hyperthyroidism
*most common* diffuse hyperplasia (Graves) hyperfunctioning multinodular goiter hyperfunctioning thyroid adenoma
cause of secondary hyperthyroidism
pituitary adenoma
primary vs secondary hyperthyroidism
elevated T3/T4 + low TSH = primary
elevated T3/T4 + high TSH = secondary
clinical presentation of apathetic hyperthyroidism
older adults with masked symptomatology
unexplained weight loss
CV disease
clinical presentation of classic hyperthyroidism
perspiration facial flushing restlessness exophthalmos palpitations/tachy diarrhea weight loss heat intolerance
thyroid storm
hyperthyroid crisis: fever tachy CHF diarrhea jaundice
thyroid storm causes
pregnancy/postpartum
hemithyroidectomy
drugs (amiodarone)
thyroid storm tx
treat manifestations:
beta blockers
treat underlying disease: high dose iodide thionamide radioiodine ablation surgery
most common etiology of hyperthyroidism
graves disease
classic diagnostic triad of graves disease
autoimmune hyperthyroidism with gland enlargement
infiltrative ophthalmology
pretibial myxedema
pathogenesis of graves disease affecting the orbit
- lymphocytes invade preorbital space
- fibroblasts have TSH receptor
- EOM swelling
- matrix accumulates
- adipocytes expand
Graves lab results
high T3/T4
low TSH
high TSI (thyroid stimulating Ig)
causes of primary hypothyroidism
Hashimoto thyroiditis
granulomatous thyroiditis
subacute lymphocytic thyroiditis
reidel thyroiditis
causes of secondary hypothyroidism
pituitary failure
hypothalamic failure
presentation of congenital hypothyroidism/cretinism
mental retardation
growth retardation
coarse facial features
umbilical hernias
etiology of congenital hypothyroidism
iodine deficiency of mother in pregnancy (endemic)
or
genetic alterations in thyroid metabolic pathways
clinical presentation of hypothyroidism/myxedema
mental/physical sluggishness weight gain cold intolerance low cardiac output hypercholesterolemia dry, brittle hair and nails diastolic HTN follicular keratosis
hashimoto thyroiditis
autoimmune hypothyroidism: auto-Ab against thyroglobulin and thyroid peroxidase
most common cause of hypothyroidism in iodide-sufficient areas
progression of Hashimoto
- immune-mediated insult
- hyperactivity and enlargement
- follicular cell exhaustion
clinical presentation of hashimoto
hypothyroid sx
exception: hashitoxicosis (early disease)
histo of hashimoto
lymphocytic infiltrate with germinal centers
Hurthle cell metaplasia: atrophic follicle cells with eosinophilic change
hashimoto Abs
hTg-Ab
hTPO-Ab
graves Abs
primarily TSHR-Ab (TSI)
but
hTg-Ab and hTPO-Ab can also be present
subacute lymphocytic thyroiditis
autoimmune!!
transient period of thyroid hormone irregularities that presents as hypo- or hyper-thyroid with goiter
can progress to permanent hypothyroidism
ex: postpartum thyroiditis
granulomatous thyroiditis
aka de Quervains
painful granulomatous response to viral infection
hypo- or hyperthyroid
Riedel thyroiditis
fibrosing thyroid process that extends into adjacent tissue
presents as euthyroid
*IgG4-related disease
histo of Riedel thyroiditis
fibrosis
lymphocytes
plasma cells
subacute lymphocytic Abs
TPO Abs
goiter
thyroid enlargement
diffuse vs nodular
nontoxic vs toxic
benign vs malignant
diffuse nontoxic goiter
endemic –> goiter due to iodine deficiency
goitrogens
sporadic
presentation of diffuse nontoxic goiter
euthyroid
sx due to mass effect: dysphagia hoarseness stridor SVC syndrome
multinodular goiters
occur due to hyperplasia and regression cycle
may have neoplastic nature
produce mass effect
which nodules are more likely to be benign: hot or cold
hot –> tx with excision or ablation
benign thyroid nodules
hyperplastic/adenomatoid nodules
follicular adenoma
malignant thyroid nodules
papillary thyroid CA
follicular/Hurthle cell CA
anaplastic CA
medullary CA
most common malignant thyroid tumor
papillary thyroid carcinoma
papillary thyroid CA mutations
RET-PTC
BRAF
histo of papillary thyroid CA
papillary architecture
psammoma bodies
“orphan annie eye nuclei”
papillary CA variants
follicular variant
tall cell variant
diffuse sclerosing
papillary CA follicular variant
follicular architecture but nuclear features of papillary
RAS mutation
papillary CA tall cell variant
older patients
aggressive!
histo looks like columnar cells
papillary CA diffuse sclerosing variant
kids and young adults
risk of metastasis but good prognosis overall
follicular CA
more common in areas with iodide deficiency
RAS mutation
PAX8/PPARG mutations
invasion properties of follicular CA
invasion of the capsule (mushroom)
angioinvasion (hematogenous mets)
anaplastic CA
very uncommon
occurs in elderly patients
highly aggressive and presents with mass effect
TP53 mutation
thyroid C cells
responsible for calcitonin secretion
medullary carcinoma
neuroendocrine tumor derived from C cells:
blue cells with dispersed chromatin
amyloid
C-cell hyperplasia
RET mutation
