Who is more likely to get hypothyroidism?
women
typically older women?
What is our classic screening test for thyroid function?
TSH
What is the best direct measurement of free T4?
go back and PANOPTO this slide 6
What is the difference between primary, secondary, and subclinical hypothyroidism?
Primary - high TSH with low free T4
Secondary - low T4 and TSH that is low or normal
Subclinical - normal T4 with elevated TSH
What is the most common cause of hypothyroidism, worldwide vs in US?
worldwide = Fe deficiency
US = Hashimoto’s Thryoiditis
What are the TSH and free T4 levels for a pt with primary hypothyroidism?
TSH - elevated
Free T4 - low
What should you suspect for a pt with elevated TSH and normal free T4?
subclinical hypothyroidism
A pts lab results are normal TSH with low free T4, what is on your ddx?
secondary hypothyroidism
but this is super rare so consider redrawing their labs again
For a patient with subclinical hypothyroidism, should they be treated?
T4 replacement is made on a case by case basis and depends partly upon the degree of TSH elevation
since they antibodies they might get worse hypothyroidism overtime
Levothyroxine
the half life of this medication is long so you have to wait for the med to build up before you can test the level —-4 - 6 weeks after dose change
What do you tell a pt who is taking levothyroxine, in regards to when to take it and what to do if you forgotten to take a pill?
take the medication on an empty stomach
don’t eat for an hour
also if they are taking Ca or iron, don’t take those within 4 hours of taking levothyroxine
if they have forgotten a pill, take 2 the next day
What defines overt hyperthyroidism?
elevated free T4, T3 or both
with subnormal TSH
How do the HTNs differ between hyper and hypothyroidism?
Hyper = systolic HTN
Hypo = diastolic HTN
How can you measure the potential proptosis in pts?
Exophthalmometer
normal in caucasian = 18mm
normal in AA = 22mm
You suspect that your pt has hyperthyroidism, you are going to refer them to endocrinology, but first what labs should you do?
TRAb - autoantibodies to the TSH receptor
TSI - thyroid stimulating immunology
TBII - thyrotropin - binding inhibitory immunoglobin
board questions might want you to say nuclear medicine uptake and scan but this is expensive
How do you treat hyperthyroidism/Grave’s?
to help with their sxs while they wait for endocrine referral
if they have tachycardia - propranolol bid (they clear the medication faster)
(also helps block T3 conversion)
Methimazole (instead of PTU d/t liver problems)
What is the treatment for thyroiditis?
propranolol
treat infection if underlying
What categories are included in the dx criterial for thyroid storm?
- Temperature
- CNS effects/Mental status
- GI dysfunction
- HR
- CHF
- A fib
- Precipitating event
What should you be thinking as a ddx if you have a pt you are treating with hormone replacement that is doing better and then all of the sudden tanks?
adrenal insufficiency? (other autoimmune disorders)
Graves Disease
Autoimmune attack of the TSH receptor antibodies (TRAB) –activating them
HypERthyroidism (MC cause)
sxs: ophthalmopahty - exopththalmos, proptosis pretibial myxedema (notpitting edema) tachycardia hyperglycemia HTN (typically systolic) heat intolerance
Dx: TSI (thyroid stimulating immunoglobins) low TSH high T3, T4 Nuclear medicine uptake and scan (RAIU) - iodine dye --more uptake in the graves thyroid
tx:
Radioactive Iodine
BB (propranolol) - this decrease tachycardia AND blocks the conversion of T4 to T3
Methimazole - blocks thyroid hormone production
Thyroidectomy - last resort or if pt is pregnant or plans on getting pregnant in the next 6 months (or males want to father in the next 6 months)
How do you dx Graves dz?
TSI (thyroid stimulating immunoglobins)
low TSH
high T3, T4
Nuclear medicine uptake and scan (RAIU) - iodine dye –more uptake in the graves thyroid
How do you tx Graves dz?
Radioactive Iodine
BB (propranolol) - this decrease tachycardia AND blocks the conversion of T4 to T3
Methimazole - blocks thyroid hormone production
Thyroidectomy - last resort or if pt is pregnant or plans on getting pregnant in the next 6 months (or males want to father in the next 6 months)
What are causes of hyperthyroidism?
Graves disease (MC)
Toxic Multinuodular Goiter
TSH secreting pituitary adenoma
Excess intake of T3 or T4
What are causes of hypothyroidism?
Iodine deficiency
Hashimotos thyroiditis
postpartum thyroiditis
post radioiodine treatment for hyperthyroidism
What are the sxs of hypothyroidism?
cold intolerance weight gain goiter myxedema hypoactivity - fatigue, sluggishness, depression hoarseness of voice bradycardia HTN, typically diastolic hypoglycemia
What are the sxs of hyperthyroidism?
Heat intolerance weight loss goiter easy bruising anxiety fine tremors fatigue urinary/deification urgency tachycardia palpitations hyperglycermia scanty periods (oligomenorrhea) HTN - systolic
Thyrotoxicosis
thyroid hormone excess - not the same thing as hyperthyroidism
What are the criteria for thyroid storm?
temperature CNS effects/mental status GI dysfunction HR CHF Afib precipitating event
Thyroid storm
potentially fatal (10-30% mortality) complication of untreated thyrotoxicosis after a precipitating event (surgery, trauma, infection, illness, pregnancy)
sxs:
hypermetabolic state- palpitations, tachycardia, A.fib, high fever, N/V, psychosis, tremors
dx:
decrease TSH, increase T4/T3
tx:
PTU or methimazole (remember that PTU has bad liver SE)
BB
IV glucocorticoids (hydrocortisone, prednisone, dexamethasone)
What is the MC cause of hypothyroid in US?
Hashimotos thyroiditis
W > M
Hashimotos thyroiditis
MC cause of hypothyroidism
self destruction of thyroid follicle cells
painless, enlarged goiter (d/t in TSH)
hypothyroid sxs
Thyroid Ab present
tx: levothyroxine (synthetic T4)
Levothyroxine
synthetic T4 given to hypothyroid pts
dont take within 1 hour of food or 4 hours of Ca/Fe pills
check TSH levels in 6 weeks since half life is 7 days so time to reach steady state would be 30 days
What is the MC cause of hypothyroid worldwide?
idoine deficiency
If a pt presents with an asymptomatic nodule on their thyroid, what do you do?
Get US
need biopsy the solid/hypoechoic nodules
never biopsy cystic/fluid nodules because they are ALWAYS benign
Starry night
microcalcifications seen on some thyroids that indicates a BAD prognosis
What thyroid nodules get biopsied?
> 1cm SOLID nodules
Subacute thyroiditis
aka Grandulomatous thyroiditis
aka de Quervian’s thyroiditis
typically viral infection of the thyroid
PAINFUL thyroid
typically presents with hyperthyroidism even though it eventually becomes hypothyroid
NO thyroid Antibodies
Elevated T3/T4
tx: NSAIDS for pain and inflammation
typically returns to normal in a year
What do the labs look like for a pt with subacute thyroiditis?
elevated T3 and T4
What is the treatment for subacute thyroiditis?
NSAIDS
NO thyroid medications since this is a viral inflammatory problem
will typically return to normal in 12 months
A pt presents with a unilateral, painful thyroid nodule, what should you be suspecting?
could be acute thyroiditis -typically caused by an infection via S. aureus
Thyroid Nodules
60% of people will have a thyroid nodule –incidence increases with age (80% women)
only 5-10% are malignant
US is the best initial testing
solitary nodule is tumor until proven otherwise
get FNA - fine needle aspiration (25 gauge needle)
Cold vs hot nodules
RIUS - radioactive iodine uptake scan
hot means that the iodine was taken up (remember that the thyroid loves iodine
cold (no/low iodine uptake) is highly suspicious for malignancy
Which thyroid cancer is the most common?
papillary (80%)
followed by follicular
What is the biggest risk factor of papillary thyroid cancer?
radiation exposure
Who is more likely to get papillary thyroid cancer?
MC in young females (20-50 y/o)
least aggressive
distant METS uncommon
excellent prognosis
Hashimotos puts you at an increased risk of papillary carcinoma
Who is more likely to get follicular thyroid cancer?
40-60 y/o
A thyroid nodule is typically benign, unless what kind of presentation?
in a pt <20 y/o
ALWAYS be suspicious of a nodule in a young pt
Medullary thyroid cancer is associated with …..
MEN 2
What is the treatment for thyroid cancer?
total thyroidectomy
Which type of thyroid has the worst prognosis?
anaplastic
Which thyroid carcinoma arises from the C cells?
medullary
Calcitonin excess production
What is measure post thyroidectomy in a medullary carcinoma to check for residual disease or recurrence?
calcitonin