Term
Compression of or damage to recurrent laryngeal nerve:
presentation?
besides thyroid surgery complication, what else can compress or damage this nerve?
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Definition
hoarseness
thyroid cancer |
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Term
T3 & T4: which one is mainly synthesized by thyroid?
which one is metabolically more active?
which one has a higher conc in blood?
which one is altered by changes in TBG levels?
how much more potent is T3 over T4?
Receptors that T3 and T4 bind to are found where in cells?
what are other locations of the receptors?
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Definition
T4
T3, which originates primarily from peripheral conversion of T4
50x concentration
T4 b/c it's 50x more in blood
5x greater; free T4 is metabolically active
nuclear chromatin receptors
membrane and mitochondrial binding sites --> extranuclear binding sites implicated in thyroid-hormone-mediated aa transport when protein synthesis is blocked |
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Term
TSH is secreted by what gland? why embrological origin?
TSH binds to what kind of receptor in thyroid follicular cells? |
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Definition
anterior pituitary - ectoderm
G-protein coupled adenylate cyclase receptor |
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Term
what is the ideal iodide intake for diet?
At what diet intake does gland function become impaired?
iodine deficiency is common where and leading cause of what (2)? |
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Definition
>200 µg/d
Less than 50 µg/d impairs thyroid gland function and T4 secretion, resulting in elevation of TSH and goiter
Iodine deficiency
–virtually non-existent in the US.
–Leading cause of goiter and hypothyroidism, world-wide
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Term
How do Children born to women with endemic goiter present?
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Definition
Mental retardation, abnormalities of hearing, gait and posture, short stature
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Term
| What drugs contain an excessive amount of iodine? |
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Definition
Amiodarone (per tablet) 75,000
Povidone iodine (per mL) 10,000
Ipodate (per capsule) 308,00000
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Term
TSH, LH, FSH, HCG
what's common amongst these hormones?
what's unique?
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Definition
hα subunits common to: TSH, LH, FSH, HCG
vΒ subunits are unique
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Term
2ndary hypothyroidism is due to?
tertiery hypothyroidism? |
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Definition
pituitary failure
hypothalamic failure (sarcoidosis or radiation) |
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Term
What are developmental causes of primary hypothyroidism?
other causes?
autoimmune
diet
congenital
drugs |
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Definition
PAX-8, TTF-2, TSH-receptor mutations
(thyroid dysgenesis) (rare)
others:
irreversible autoimmune destruction: Hashimoto's disease
(Characterized by antibodies to TPO and thyroglobulin)
late grave's disease
subacute thyroiditis (3 phases: hyper/hypo/return to euthyroid)
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Postablative
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Surgery, radioiodine therapy, or external radiation - tx hyperthyroidism
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Iodine deficiency- JOD BASEDOW phenomenon
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Drugs (lithium for manic depression,
iodides (seaweed),
amiodarone**,
propylthiouracil (to tx grave's)
methimazole - antithyroid drug,
interferon α or β)
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Congenital biosynthetic defect (dys-hormonogenetic goiter) - enzymatic disorder
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Thyroid hormone resistance syndrome (TRβ mutations)
Down's syndrome
~50% →chronic lymphocytic thyroiditis
**other side effects: interstitial lung disease, corneal deposits
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Term
A 45-yr old woman presents with a swelling in anterior neck. slowed speech, easy fatigability, and cold intolerance. She has RA (aha! another autoimmune disorder) for which she is taking NSAIDs.
PE: puffy face, dry skin, coarse hair, swelling of thyroid gland in anterior portion of neck, swelling is mobile with deglutition but not with protrusion of tongue, thyroid has rubbery consistency; right lobe more enlarged than the left; swan neck deformity of left ring finger; ulnar deviation of fingers of both hands
Labs: free T4 and free T3 low; TSH high; antithryroglobulin and antimicrosomal antibodies detected by ELISA
Imaging: nuc: decreased radioactive iodine uptake (RAIU)
Histo: massive infiltration by lymphocytes and plasma cells, normal follicles not present; scant colloid; eosinophilic (bright pink stain indicates basic proteins/cytoplasm) Hurthle cell degeneration
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Definition
Hasimoto thyroiditis
increases risk of developing B-cell non-Hodgkin lymphomas |
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Term
What condition is an endocrine emergency?
describe it
signs? |
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Definition
myxedema coma
20% mortality
severe hypothyroidism that has been prolonged and untreated precipitated by cold, sepsis, thyroidectomy, trauma and drug interactions (lithium, amiodarone, sedatives, narcotics)
signs:
slowness (speech, movement), coma, hypothermic, obviously myxedematous, bradycardic, unresponsive and frequent development of respiratory failure, fluid overload, pericardial effusion
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Term
| How do you treat myxedema coma? |
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Definition
Admit to Intensive Care Unit- it is life threatening
Support all vital signs ;
Blood pressure - fluids
–Respiratory system- may intubate
–IV thyroxine 200-400 ug IV and 300 ug iv daily
–Stress doses of hydro-cortisone to make sure adrenal insufficiency is not precipitated.
–Evaluate for underlying illness: sepsis, infection, MI CVA, Meds, pericardial effusion, etc.
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Term
ddx for thyrotoxicosis
(overproduction of thyroid hormone)
[NB: difficult card] |
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Definition
Primary:
Grave's disease (60%) esp for females in 30s-40s
toxic multi-nodular goiter
thyrotoxic phase of thyroiditis (subacute thyroiditis or pseudogranulomatous DeQuervain's, painless lymphocytic thyroiditis (Hashimoto's), post-partum thyroiditis)
toxic adenoma
iodine-induced
amiodarone-induced
excess b-HCG from molar pregnancy or choriocarcinoma
metastatic thyroid carcinoma
goitrogens
ectopic/exogenous/factitious (exess ingestion of T3 --> thyrotoxicosis factitia; struma ovarii - thyroid hormone producing)
secondary:
pituitary related i.e. TSH producing pituitary adenoma that increases thyroid hormone production; thyroid hormone resistance
tertiary:
hypothalamus: too much TRH which increases TSH and T4/T3 serum (TRH is not measurable in blood)
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Term
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Definition
| enlarged thyroid weighing more than 50g (normal weight is 25g) |
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Term
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Definition
veggies like cabbage, turnips, brussel sprouts, cauliflower, cassava
drugs like lithium and cobalt |
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Term
What causes Grave's disease?
what triggers the disease? |
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Definition
thyroid stimulating immunoglobulin (TSI) or long acting thyroid stimulator (LATS): IgG that bind and activate the G-coupled receptor TSH receptor in thyroid follicular cells
IgGs act like TSH and cause follicle hypertrophy, increased thyroid size and thyroid hormone production and drop in TSH
(eye muscles have TSH receptors --> increased connective tissue pushing the eye fwd --> mechanism underlying proptosis)
susceptible pt's are triggered by stress, infection, iodine intake, smoking and interferon alpha |
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Term
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Definition
TOP
Graves disease. A, There is diffuse symmetric enlargement of the gland and a beefy deep red parenchyma
B, Diffusely hyperplastic thyroid in a case of Graves' disease. The follicles are lined by tall, columnar epithelium. The crowded, enlarged epithelial cells project into the lumens of the follicles. These cells actively resorb the colloid in the centers of the follicles, resulting in the scalloped appearance of the edges of the colloid.
(red line)
BOTTOM
Papillary carcinoma of the thyroid. A, The macroscopic appearance of a papillary carcinoma with grossly discernible papillary structures. This particular example contains well-formed papillae
(B), lined by cells with characteristic empty-appearing nuclei, sometimes called “Orphan Annie eye” nuclei (C). D, Cells obtained by fine-needle aspiration of a papillary carcinoma. Characteristic intranuclear inclusions are visible in some of the aspirated cells.
Source of pictures: Robbins
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Term
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Definition
proptosis, dermopathy, onycholysis, hyperthyroidism =
signs of Grave's disease |
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Term
thyroid storm
how do you treat it? |
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Definition
Thyroid Storm - Severe thyrotoxicosis; intense response to thyroid hormones - levels may be normal
–Fever, infection, hi heart rate, CV collapse, death
tx:
hydration, PTU or methimazole, hr later give iodine to block release of thyroid hormone, glucocorticoids
avoid ASA
ID and tx underlying cause of thryotoxicosis ie sepsis or MI
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Term
| apathetic hyperthyroidism |
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Definition
Elderly - Apathetic hyperthyroidism-
–hyperthyroidism presents w/ CV findings without peripheral adrenergic symptoms- slow and depressed - no hyper-reflexia or hyperkinetic activity or irritability
–Depression, atrial fibrillation, cachexia/wgt loss, angina
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Term
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Definition
•In most patients, the nodule produces too little thyroid hormone to cause hyperthyroidism
•Generally must be >2.5 cm to cause clinical hyperthyroidism (“toxic adenoma”)
• Constitutively activating mutations of the TSH receptor are causative in many cases
vThionamides will lower T4 and T3, but will not lead to cure.
v
vTherefore, preferred therapy is surgery or radioiodine.
v
vThe patient can be followed without therapy if she/he is euthyroid (normal TSH).
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Term
A 30 y.o. woman had a respiratory illness a week ago, now c/o rapid heart beat, sweating, neck pain and redness, especially noting tenderness to touch
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Definition
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•subacute thyroiditis
•Leakage of thyroid hormone from damaged thyroid cells, rather than increased synthesis, is the cause of thyroid hormone excess.
–Therefore, the radioiodine uptake is low.
•Resolves spontaneously after 2-3 months.
•
Thyrotoxic phase may be followed by a hypothyroid phase, also lasting 2-3 months.
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Term
| Why are antithyroid drugs contraindicated in subacute thyroiditis even though it's hyperthyroidism? |
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Definition
The hyperthyroidism is because thyroid cells have been destroyed and liberated stored thyroid hormone.
There is no where for propylthiouracil or methimazole to act since it is not a disease of overactive cells.
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Term
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Definition
95% benign
5:1 female:male ratio |
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Term
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Definition
Normal thyroid, calcitonin stain for C cells that releases calcitonin --> lower serum Ca2+
(not stained under H&E)
follicles: epithelial follicular cells that are cuboidal or columnar in shape with central lumen known as colloid
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Term
Normal location of thyroid gland
other locations? |
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Definition
inferior to cricoid cartilage: butterfly shaped 2 lateral lobes connected by an isthmus ~25g
other locations:
sublingual/lingual
prelaryngeal
substernal |
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Term
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Definition
Hashimoto thyroiditis. painless thyroid enlargement with low thyroid hormones and elevated TSH due to autoimmune antibodies
A. The thyroid parenchyma contains a dense lymphocytic infiltrate with germinal centers. Residual thyroid follicles lined by deeply eosinophilic Hurthle cells are also seen.
B. more advanced stage. almost all lymphocytes. germinal center. pink epithelium = hurthle cell hyperplasia
C. end stage. fibrotic thyroid. residual lymphocytes. hurthle cell hyperplasia. basically no functioning thyroid left
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Term
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Definition
Subacute or granulomatous thyroiditis. painful thyroid enlargement due to viral infection (URT infection)
aggregations of lymphocytes, histiocytes and plasma cells. multinucleate giant cells (above left) enclose pools of colloid (bottom right)
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Term
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Definition
Multinodular goiter.
may compress the trachea and/or esophagus and have to be surgically removed
A, Gross morphology demonstrating a coarsely nodular gland, containing areas of fibrosis and cystic change. gelatinous nodules
B, Photomicrograph of a hyperplastic nodule, with compressed residual thyroid parenchyma on the periphery. Note absence of a prominent capsule, a distinguishing feature from follicular neoplasms.
C. lined by follicular epi that underwent atrophy; no papillations
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Term
MULTIPLE ENDOCRINE NEOPLASIA SYNDROMES
MEN1
MEN2A
MEN2B
familial diseases - diagnose early
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Definition
•MEN-1: Pituitary, Parathyroid, Pancreatic Islets, Adrenal Cortex
•MEN-2A: Pheochromocytoma, Medullary Carcinoma of the Thyroid
•MEN-2B: same as MEN-2A + Mucocutaneous Ganglioneuromas
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Term
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Definition
A. papillary carcinoma
B. papillary carcinoma
C. follicular adenoma
D. Hurthle cell adenoma (follicular adenoma)
E. follicular carcinoma
F. follicular carcinoma
G. psammoma bodies (papillary carcinoma)
H. nuclear grooves (papillary carcinoma)
I. nuclear pseudoinclusions (papillary carcinoma)
J. Anaplastic carcinoma
K. anaplastic carcinoma
L. medullary carcinoma |
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Term
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Definition
Gross specimen
A. Anaplastic carcinoma
B. Medullary carcinoma
C. Follicular Carcinoma
D. Papillary Carcinoma
E. Multinodal Goiter
F. Graves disease
G. Follicular adenoma |
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Term
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Definition
Special papillary carcinoma
A. tall cell variant
B. follicular variant
C. papillary microcarcinoma |
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