Thyroid & Parathyroid Flashcards
Three functions of T3/T4
metabolism
HR & Contractility
Development
+ TPO Abs…
hashimotos
MC Cause of primary hypothyroidism…
hashimoto thyroiditis
Increased TSH
Decreased FT4
Decreased FT3
Primary hypothyroid
Increased TSH
Normal FT4/FT3
Subclinical hypothyroid
Normal/low TSH
Low-Normal/low FT4
Normal/low FT3
Central Hypothyroid
Transient hyperthyroid common with early Hashimoto’s Thyroiditis
hashitoxicosis
This is autoimmune mediated destruction of thyroid gland
Gradual loss of fxn w/ inflamation
Hashimoto Thyroiditis
2 factors that cause hashimoto thyroiditis?
genetic susceptibility, environmental factors
The below are precipitating factors for…
Viral infx Stress Pregnancy Iiodine intake Radiation
Hashimoto thyroiditis
What Abs are (+) in hashimoto thyroiditis?
TPO Ab (MC) TgAb
+/-TRAb
Tx for hashimoto thyroiditis
levothyroxine 1.6 mcg/kg/day
*weight based dosing
Who should receive a lower synthroid dose initially?
> 60, cardiac concerns
Describe the dosing regimen for synthroid?
empty stomach 1 hr before breakfast
The below can have what effect on hashimoto thyroiditis tx?
ferrous sulfate
calcium carbonate
PPIs
Bile acid resins
interfere w/ synthroid absorption
take them 4 hours after T4
When should hashimoto thyroiditis sxs begin resolving after starting synthroid?
2-4 weeks
When should a repeat TSH after starting synthroid for Hashimotos occur?
6 weeks after tx
How long is therapy with synthroid for hashimotos over the life-cycle?
life-long tx
Patient presents with…
mild or vague sxs of constipation, fatigue, depression
Normal T4, elevated TSH
Subclinical hypothyroidism
The below are consequences of…
NAFLD Neuropsych sxs Infertility Miscarriage CV disease
subclinical hypothyroidism
How do you confirm a dx of subclinical hypothyroidism?
Repeat TSH/T4 after 1-3 mo
Tx for subclinical hypothyroidism should occur if TSH is _____ or higher
10
Increased TSH and Decreased T4
Presents w/
AMS, hypothermia, hypoventilation
hyponatremia, hypotension, fatal arrhythmia
Myxedema coma
What 4 things can precipitate myxedema coma?
stroke, HF, infx, Trauma
Tx for myxedema coma?
IV thyroxine & triiodothyronine (T3)
Pt. presents w.
weight gain, fatigue, constipation…
hypo or hyper
hypothyroid
3 causes of hyperthyroid
Graves (MC)
Toxic Adenoma
Toxic Multinodular Goiter
Pt. presents w.
Weight loss, exopthalmos, periorbital edema, increased appetite, tachy, palpitations
hyper or hypothyroid?
Hyperthyroid
TSH decreased
FT4/T3 Increased
Primary hyperthyroidism
graves
TSH Decreased
FT4/T3 Normal
Subclinical hyperthyroidism
TSH Decreased
Normal FT4
T3 Increased
T3 toxicosis (early graves)
RAIU Scan is contraindicated for (2)
pregnancy
breast feeding
RAIU result for Graves…
diffuse elevated
RAIU Result…
Diffuse decreased/absent uptake
thyroiditis/exogenous hormone
RAIU Result
Focal Elevated uptake
hot nodule
RAIU Result
Focal decreased uptake
cold nodule
This is an autoimmune mediated stimulation of the thyrotropin receptor. It is the MC cause of hyperthyroidism
Graves
What two conditions are the 2nd most common cause of hyperthyroidism?
Toxic MNG (hyperplasia) Toxic adenoma (nodules)
Patient presents with:
lid retraction lid lag ptosis goiter proptosis
Graves
(+) TRAb indicates…
graves
TRAb result for toxic adenoma and toxic mng…
negative TRAb
RAIU results for toxic adenoma/toxic mng…
focal uptake
A patient presents with the following labs and S/S.
Decreased TSH, Increased T4/T3
Agitation, delirium, fever, tachy, vomiting, dehydration
Thyroid storm
What is symptomatic treatment for hyperthyroidism?
Atenolol/Propranolol
What medications decrease thyroid hormone synthesis?
Methimazole (DOC)
PTU (pregnancy)
What are two definitive txs for hyperthyroid?
radioiodine ablation (1st line) surgery (obstructive sxs/severe dz)
This thioamide has the below characteistics
QD dosing
Rapid efficacy
low sfx
methimazole
Three C/I for radioiodine ablation…
active ophthalmopathy
pregnancy
lactation
What is the progression of thyroid levels with subacute thyroiditis?
Hyperthyroid, Euthyroid, Hypothyroid, Euthyroid
What are you concerned for?
Preceding viral illness
painful gland enlargement
radiating pain to jaw/neck
fever, fatigue, anorexia
subacute thyroiditis
How is subacute thyroiditis diagnosed?
clinical
Management for subacute thyroiditis
aspirin/NSAIDs +/- prednisone
monitor TSH
MC malignant thyroid nodule…
papillary carcinoma
Thyroid nodules are associated with FHx of…
thyroid CA, MEN-2
Benign or malignant US results?
colloid
< 1 cm
cystic
benign
Benign or malignant US results?
taller than wide solid irregular margins microcalcification > 1 cm
malignant
What is the most aggressive form of thyroid cancer?
anaplastic
which type of thyroid cancer mets to bone, brain, lung, liver
follicular
What is the diagnostic workup for thyroid cancer?
4
US
RAIU
FNA
CT/MRI/PET
What does tx of thyroid Ca look like?
thyroid lobectomy/total thyroidecomy \+ iodine ablation \+ Levothyroxine
surgery on thyroid ca can result in what two complications?
injury to left recurrent laryngeal
hypoPTH
Patient presents with…
Prolonged QT chvostek Trousseau tetany carpopedal spasm
hypoPTH
The following labs indicate…
Low PTH
Low Ca
Normal/low Vit. D
Normal/low Mg
High PO4
HypoPTH
mild hypoPTH can be treated with…
calcitriol (1,25) and calcium carbonate
If hypoPTH with tetany or prolonged QT, tx with
emergent IV calcium gluconate
If hyperphosphatemia with hypoPTH, add…
phosphate binders
If hypomagnesemia with hypoPTH, add..
magnesium
MC cause of primary hyperPTH…
parathyroid adenoma
Secondary hyperparathyroidism is often caused by…
CKD (decreased vit. D production)
What is the common presentation of hyperPTH?
bones, stones, abdominal moans, psychiatric groans
High PTH
High Ca
Low PO4
primary hyperPTH
High PTH
Low Ca
High PO4
secondary hyperPTH
What additional imaging modality should be used to evaluate for osteopenia/porosis with PTH disorders?
DEXA
What drugs must be avoided for fear of aggrevated hypercalcemia with hyperPTH?
HCTZ
What is definitive tx for hyperPTH?
parathyroidectomy
Primary hyperPTH with parathyroid ademona PTH/Ca…
high
Secondary HyperPTH with renal disease PTH/Ca…
High PTH
Low Ca