Low TSH Approach Flashcards
Physical findings of low TSH
- radiate heat
velvety skin
tremor
nail changes: onycholysis
pulse: rate and rhythm– tachycardia and AFib
low tsh = __thyroidism
hyper– thyroid hormones are not regulated.
Circulatory system of low TSH:
___ in diastolic pressure due to decresed ___ ___
___ systolic pressure due to ___ ___.
what does this lead to?
- increase in ___ mass
- high output heart failure
- _____ arrhythmias
DECEASE in diastolic pressure due to decresed PERIPHERAL RESISTANCE
INCREASED systolic pressure due to MYOCARDIAL CONTRACTILITY.
what does this lead to?–> leads to widened pulse pressure, stroke volume increase, nad hyperdynamic circulation signs
- increase in LV mass
- high output heart failure
- superventricular arrhythmias
To assess proximal muscle weakness, you must compare:
proximal to distal muscle strength
how do tendon relfexes change in hyperthyroidism?
brisk deep tendon reflexes, both in contraction and relaxation
opthalamologic changes in hyperthyroid
lid retraction and lid lag
lab tests in huperthyroid:
TSH is ___, free T4 is _____.
If tsh is normal, the person is considered ___.
If the level of free T4 is normal, its called ___ ___
TSH is LOW, free T4 is HIGH.
If tsh is normal, the person is considered EUTHYROID.
If the level of free T4 is normal, its called SUBCLINICAL HYPERTHYROID
COMMON causes oh hyperthyroidism
iatrogenic
graves
thyroiditis
hot single nodule
multinodular goiter
rare causes of hyperthyroidism
hydatidform mole GCG
TSH secreting pituitary tumor, resulting in excessive T3 production
struma ovarii
cause of this ocular finding
GRAVES OCULOPATHY PROPTOSIS. both the bottom and top iris is not covered by lid.
Associated autoimmune endocrine diseases of Graves.
Graves have increased risk of also developing:
hashimotos thyroiditis
premature ovarian/testicular insufficiency
type 1 diabetes mellitus
addisons disease (adrenal insufficiency)
classic thyroid scan finding of subacute thyroiditis
recall; thyroiditis releases a bunch of Thyroxins from the colloid– there is nothing holding it back from the follicle. therefore, you owuld not see trapping on the thyroid scan– you would not see much uptake of radioiodine
Cause of subacute thyroiditis
often post-viral
4 thyroiditis variations
- subacute (post-viral)
- post-partum
- painless
- Drugs (amiodorone)
Release of pre-formed stored thyroid hormone,
TSH is suppressed, and the gland is not working
(no iodine uptake and no hormonogenesis),
until complete recovery
T/F thyroiditis can be a chronic condition
false. it’s self-limited. the gland doesn’t work and releases all the pre-formed stored thyroid hormone. but when it empties, thyroiditis will stop.
hyperthyroid patients often have a hot nodule– a single paplable nodule, where the rest of the thyroid gland is small. when might you see hyperthyroidism due to a MUTLINODULAR goiter?
you should consider a multinodular goiter causing hyperthyroidism vs a hot nodule if it is a longer standing process, and older age group, and secondary complications because of enlargmenet of goiter– esophageal compression, tracheal stenosis and hoarseness
hot nodule or multinodular?
Lab, physicla, nuclear scan uptake findings of thyrotoxicosis
lab; low serum TSH, free T4 and T3. Anti-TSH receptor antibodies for Graves
phsical: feel thyroid for nodularity, look at eye changes, bruits, symptoms of hyperthyroidism (higher temperature)
nuclear med uptake: one large spot for single nodular hyperthyroidism, high amount of uptake in both lobes in graves, no uptake in thyroiditis
Outline a general scheme for an approach to diagnosis of cause of hyperthyroidism
4 broad treatment options for hyperthyroidism
- medical
- surgical
- radioiodine
- observe.
contraindications for using radioactive iodine
preganncy, lactation, active oculopathy
- must be caregul because sometimes after years of taking radioactive iodine, hypothyroidism is seen
Antithyroid drug mechanisms and side effects
blocks thyroid hormonogenesis: two types; propylthiouracil and methimazole
problems: skin reactions (espeically when you stop it), agranulocytosis, hepatitis, vasculitis; SLE-like
- arthralgias
- 50% relapse into hyperthyroidism when you stop the drugs
when should you use beta blockers when treating hyperthyroid
for tremors, palpitations, anxiety, marked tachycardia.
ONLY USE UNTIL EUTHYROID, then stop
Fill out this Graves Disease table
Subclinical hyperthyroidism
Serum TSH __ __
- Serum free T4 __, and T3 __
- 0.6 - 2.2 % prevalence
natrual history?
serum TSH below normal
serum free T4 normal and T3 normal
Natural history of subclinical hyperthyroidism can recover or progress to overt hyperthyroidism
Note; subclinical hyperthyroidism treatment is pretty lacklustre– not much data
