Thyroid Path Flashcards
elderly adult with unexplained weight loss and cardiovascular disease may have
apathetic hyperthyroidism
name the components of the burch-wartofsky score
- fever
- cardiac (tachy, CHF)
- GI (jaundice, diarrhea)
- precipitating history (pregnancy/postpartum, hemithyroidectomy, amiodarone)
describe the treatment of thyroid strom
- PTU
- B-blockers
- steroids
why is PTU used in the treatment of thyroid storm?
inhibits:
- peroxidase
- peripheral conversion of T4 —> T3
pt presents with arrhythmia, fever, vomiting and hypovolemic shock, consider…
thyroid storm
“tachycardia will be out of proportion to fever”
- hyperthyroidism with gland enlargement
- infiltrative opthalmopathy
- pretibial myxedema
grave’s disease
scalloping
grave’s disease
T3/T4: high
TSH: low
TSI: high
grave’s disease
describe the pathogenesis of pretibial myxedema and exophthalmos in graves disease
fibroblasts express TSH receptor
activation –> glycosaminoglycan (chondroitin sulfate and hyaluronic acid) buildup, inflammation, fibrosis, and edema
what type of hypersensitivity reaction is grave’s disease?
TIIHSN
IgG autoAb stimulate TSH receptor; MC AB is TSI
what changes are responsible for the increase in BMR in hyperthyroidism?
increased synthesis Na-K ATPase
what changes are responsible for the increase in sympathetic activity in hyperthryroidism?
increased expression B1-adrenergic receptor
describe the presentation of cretinism
- growth and mental retardation
- coarse facial features
- umbilical hernia
- enlarged tongue
one cause of cretinism is dyshormonogenetic goiter, which is due to…
congenital defect in thyroid hormone production – most commonly involving thyroid peroxidase
other causes: thyroid agenesis, maternal hypothyroidism
thyroglossal duct cyst presents as
anterior neck mass
lingual thyroid presents as
base of tongue mass
this is persistence of thyroid tissue at the base of the tongue
multinodular goiter is due to
iodine deficiency
how is cassava root a goitrogen?
a thiocyanate; inhibits iodide transport in thyroid
how does a toxic goiter develop?
regions of a multinodular goiter become TSH-independent —> release T4 —> hyperthyroidism
what age group is affected by myxedema?
older children and adults
is hyperglycemia seen in hyper or hypothyroidism?
explain why
hyperthyroidism
TH causes gluconeogenesis and glycogenolysis effects
is hypercholesterolemia seen in hyper or hypothyroidism?
hypothyroidism
note: cardiac output is decreased, bradycardia
in hypothyroidism, this results in a deepening of the voice and large tongue
myxedema
pts also have cold intolerance, weight gain, and mental and physical slowing
what are the most common causes of myxedema?
iodine deficiency and Hashimoto thyroiditis
also: lithium; surgical removal or ablation of thyroid
Hashimoto thyroiditis is associated with HLA…
DR5
initially Hashimoto may present as hyperthyroidism, why?
follicle damage – release of hormones
aka Hashitoxicosis
Hashimoto will progress to presenting with…
hypothyroidism; low T4 & elevated TSH
Hashimoto has autoAbs against…
thyroglobulin (Tg) & thyroid peroxidase (TPO)
possibly: anti-microsomal
histology:
chronic inflammation (lymphocytic infiltrate) with germinal centers & Hurthle cells (eosinophilic metaplasia of cells lining the follicles)
Hashimoto thyroiditis
Hashimoto thyroiditis results in increased risk for
B-cell (marginal zone) lymphoma
enlarging thyroid gland late in Hashimoto thyroiditis disease course is concerning for
B-cell (marginal zone) lymphoma
name the four euthyroid diseases
- granulomatous (+)
- subacute (-)
- Riedel*
- neoplasms
*really, only hypothyroid (-)
transient period of thyroid hormone irregularities (usually hypo), +/- goiter, painless
subacute lymphocytic thyroiditis
ex: postpartum thyroiditis
this thyroiditis is painful, tender; possibly viral in origin
(usually hyper)
subacute granulomatous (de Quervian) thyroiditis
subacute granulomatous (de Q) thyroiditis is associated with HLA…
B35
a young patient with a hard as wood and nontender thyroid…
riedel fibrosing thyroiditis
riedel fibrosis may extend to involve
local structures, such as the airway
how can you differentiate between riedel fibrosing thyroiditis and anaplastic carcinoma?
patient’s with riedel are younger (40s)
a thyroid that is very pale after excision likely had what disease process?
riedel fibrosing thyroiditis
which thyroiditis is considered an IgG-4 related disease?
riedel fibrosing thyroiditis
will show fibrosis (duh), lymphocytes, and plasma cells
what cells secrete IL-10 and TGF-B to induce IgG4 production and fibrosis?
Treg
IL-10 —> B cells & plasma cells
TGF-B —> fibroblasts
what are the three more common IgG-4 related diseases?
- autoimmune pancreatitis
- sclerosing mediastinitis
- idiopathic retroperitoneal fibrosis
name the mass effect symptoms of a goiter
- dysphagia
- hoarseness
- stridor
- SVC syndrome
thyroid scintigraphy isn’t great for determining malignancy but between hot and cold, which is more likely to be malignant?
cold
on uptake, graves disease and nodular goiter are usually
hot
on uptake, adenoma and carcinoma are usually
cold
benign proliferation of follicles surrounded by a fibrous capsule
follicular adenoma
what age group is papillary thyroid carcinoma seen in?
25-50
what is the most common type of thyroid carcinoma?
papillary carcinoma (80%)
good prognosis (10 yr survival >95%)
what is a major risk factor for papillary thyroid carcinoma?
exposure to radiation in childhood (chernobyl)
histology:
papillae lined by cells with clear “orphan annie eye” nuclei and nuclear grooves; psammoma bodies
papillary thyroid carcinoma
where does papillary thyroid carcinoma spread?
cervical LNs
how does papillary thyroid carcinoma present?
it is usually asymptomatic; palpable nodule or ultrasound possible
age is a significant factor in the staging of
thyroid carcinoma
RET-PTC & BRAF mutations
papillary thyroid carcinoma
what papillary thyroid carcinoma variant has RAS mutations?
follicular variant
*RAS mutations are not specific though
what papillary thyroid carcinoma variant is seen in elderly patients? it is aggressive
tall cell variant
what papillary thyroid carcinoma variant is seen in kids and young adults?
where does it mets?
diffuse sclerosing variant
lung, brain, bone and liver
- this variant has the tendency to recur and is aggressive, but has a good prognosis
RAS and PTEN mutations are seen in the follicular carcinoma, however this is not specific. which mutation is specific?
PAX8/PPARG fusion gene
recall RAS is also seen in follicular variant of papillary thyroid carcinoma
what two types of invasion are seen in follicular carcinoma?
mushroom invasion (of the capsule) & angioinvasion
how does follicular carcinoma of the thyroid mets?
hematogenously (b/c of angioinvasion)
a rapidly enlarging, bulky neck mass in a pt 65+ with dysphagia and respiratory compromise is concerning for
anaplastic carcinoma of the thyroid
histology:
orphan annie eye nuclei
speckled necrosis
large cells
anaplastic carcinoma
an undifferentiated malignant tumor
constitutive tyrosine kinase activity in papillary carcinoma is due to what mutation?
RET/PTC
MAP kinase signaling in papillary carcinoma is due to what mutation?
BRAF
what thyroid carcinoma has TP53 mutations?
anaplastic
histology:
cells are larger and have more cytoplasm
what is their secretory product?
parafollicular c cells of the parathyroid gland – they secrete calcitonin
histology:
blue cells with dispersed chromatin; salt and pepper
amyloid
sheets of neuroendocrine cells
c-cell hyperplasia
medullary carcinoma
calcitonin lowers serum calcium by…
increasing renal excretion of calcium
familial or sporadic medullary carcinoma?
50; unifocal, aggressive
sporadic
70-80% of medullary thyroid carcinomas
familial or sporadic medullary carcinoma?
43; multifocal, best prognosis
familial
familial cases of MTC are often due to…
MEN 2A and 2B
what mutation warrants prophylactic thyroidectomy?
RET – familial MTC/MEN
describe how a pt with MTC could present with hypocalcemia
tumor produces high levels of calcitonin
*monitor calcitonin for progress of the tumor
parathyroid hyperplasia, pheochromocytoma; MTC
normal body habitus
MEN 2A
“2 Ps)
pheochromocytoma, oral and intestinal ganglioneromatosis; MTC
marfanoid body habitus
MEN 2B
“1 P”
