thyroid disorders Flashcards
what is the function of the thyroid gland
produced thyroid hormones that control the rates of metabolic processes throughout the body
what is the sole purpose of iodine
to maintain euthyroid
what are some of the function of T3&T4
regulated catabolism metabolic rate heat production GH secretion and skeletal maturation CNS development muscle tone GI secretions respiration
what are anti thyroid peroxidase
these are circulating antibodies against thyroid peroxidase
used to detect thyroid disorders
what is a goiter
an increase in the size of the thyroid gland
can occur in hyer/hypo or euthyroid
can be diffuse or nodular
due to hypertrophy of tissue from thyroid hormone
what is the pembertons sign
large substernal goiters can cause superior vena cava syndrome
facial erythema and cyanosis when both arms are raised over the head
What is congenital hypothyroidism
very rare and preventable
usually a child born without or half of a thyroid
Can also be due to lack of producing function thyroid
what are the signs and symptoms of congenital hypothyroidism
mental retardation
growth impairment
poor psychomotor development
that is the treatment for congenital hypothyroidism
screening at birth with hormone supplement
what are types of autoimmune hypothyroidism
hasimotos thyroiditis, atrophic thyroiditis
what are types of drug induced hypothyroidism
iodine excess, amiodarone, iodine contrast media, lithium, antithyroid drugs
what are the most common causes of hypothyroidism world wide
iodine deficiency
what is the most common cause of hypothyroidism in the US
autoimmune
what are some infiltrative and surgical processes that can cause hypothyroidism
amyloidosis, sarcoidosis, hemochromatosis
thyroidectomy
what are causes of transient hypothyroidism
sub acute thyroiditis
withdrawal of thyroxine Tx in individuals with an intact thyroid
what are secondary causes of hypothyroidism
hypopituitarism
hypothalamic disease
what is the most common form of thyroiditis and most common cause of thyroid disease in the US
hashimotos thyroiditis
what symptoms of hypothyroidism
weight gain fatigue/lethargy depression constipation dry skin cold interolerance weakness DOE muscle cramps heavey/light or no period
what are signs of hypothyroidism
bradycardia thin brittle nails thinning hair puffy face/eyelids pale skin
what are signs and symptoms that are unique to hashimotos
initially present with transient hypoerthyroidism due to destruction of thyroid
many present b/c of non-tender goiter initially and then later in the disease they will present with the common signs/symptoms of hypothyroidism
what will the serum TSH and FT4 be like for primary hypothyroidism
will be elevated
FT4 will be normal or low
if hashimotos antibodies against thyroperoxidase are high
what are TSH and FT4 values like with secondary hypothyroidism
low or normal
low or normal
what are the other lab abnormalities like with hypothyroidism
increased serum LDL, cholesterol, triglycerides, lipoprotein, liver enzymes, and creatine kinase, hyponatermia, hypoglycemia and anemia
what is subclinical hypothyroidism
patients w/ normal FT4 and mildly elevates TSH
maybe benefit thyroid replacement
if they are asymptomatic then there is no need to replace just monitor for symptoms
when should you use imaging
usually not necessary
If a goiter is present and asymmetric the ultra-sound should be indicated to show if there is solitary lesion or multinodular goiter
if a solitary lesion/focal nodule is present fine needle aspiration is recommended
what are some complications of hypothyroidism
myxedema infertility miscarriage cardiac complications megacolon increased risk of bacterial pneumonia
what is the mainstay treatment for hypothyroidism
levothyroxine
when started on levothyroxine treatments are started when should TSH levels be monitored
6-8weeks after initiation
how long will it take for the replacement take to be effective
3-6 months
how should the dosages be adjusted for treatment with levothyroxine
small increments of 12.5-25ug/day
what should you do with your patient once normal levels are maintained and stable for 1 year
follow up with TSH on annual basis
what should you start pt<60 yo with heart disease
50-100ug
what is the starting dose for elderly patients?
12.5-25ug much lower than younger patients
what happens if you do not treat a pregnant women with hypothyroidism
may affect fetal neural development and cause preterm labor
when should you check thyroid for pregnant women
2nd and 3rd trimesters
what should you do with women who have known hypothyroidism
increase their levothyroxine by 50% during pregnancy
what is myxedema crisis
severe life threatening hypothyroidism
what are the symptoms of myxedems crisis
impaired cognition
convulsions and abnormal CNS signs
severe hypothermia, hypoventilation, hyponatremia, hypoglycemia, and hypotension and kidney injury
who is myxedema crisis most common in
women who have had a stroke or stopped thyroid meds
what is the treatment for myxedema crisis
rapid thyroid hormone replacement and supportive therapy
what is hyperthyroidism
a condition in which the thyroid gland is overactive, making too much thyroid hormone
what are types of primary hyperthyroidism
graves, toxic multinodular goiter
struma ovarii
drugs
what are causes of transient hyperthryoidism
subacute thyroiditis
thyroid destruction
thyrotoxicosis factitia
what are causes of secondary hyperthyroidism
TSH pituitary adenoma
thyroid hormone resistance
molar pregnancy
gestational thyrotocixcosis
what is the most common cause of hyperthyroidism
graves disease
when is graves disease
autoimmune disease affecting the thyroid gland characterized y an increase in synthesis and release of thyroid hormones
what increases the risk factors for hyperthyroidism
high iodine intake as well as medication use (potassium iodide, amiodarone-contain iodine)
genetics
what is the pathogenisis of graves disease
caused by production of antibodies to the thyroid glands TSH receptors
Ab stimulate the receptor and are called thyroid stimulating immunoglobulins which leads to increased thyroid gland hormone production
what age group is graves disease most common age
20-50years old
more common in women
what is toxic single/multinodular goiter
autonomouslt secreting nodules produced thyroid hormone w/o the need for TSH receptor stimulation
what is single toxic nodule hyperthyroidism
plummers disease
what is granulomatous thyroiditis (dequervain thyroiditis)
initially inflammation causes thyroid follicle destruction with release of thyroid hormones, followed by period of hypothyroidism while glands are recovering and then euthyroid returns
what is lymphocytic thyroiditis
causes brief thyrotoxic state followed by hypothyroidism then resolution
common in postpartum women
what are other causes of hyperthyroidism
ovarian teratoma metastatic thyroid cancer pituitary tumor Iodine-induced amiodarone
what is the jod baselow effect
occurs in patients with an endemic goiter who relocated to an iodine abundant geographical area
what are symptoms of thyrotoxicosis/hyperthyroidism
hyperactivity heat intolerance and sweating palpitations weight loss despite increased appetite diarrhea polyuria
what are signs of hyperthyroidism
tachycardia tremor goiter warm moist skin palmar erythema lid retraction or lag fever
what are signs specific to graves disease
enlarged thyroid with a bruit due to vascularity of gland
lid retraction, periorbital edema, conjunctival injection proptosis, visual disturbance
pretibial brawny thickening of skin
what are the lab values like for hyperthyroidism (TSH,FT4,T3)
TSH-low
FT4-elevated
T3-norm or elevated
what is elevated erythrocyte or ESR indicative of
subacute thyroiditis
what is ultra sounds useful for with thyroid disorders
helpful for patients with palpable thyroid
what is a thyroid scan used for
used to evaluate uptake radioactive iodine in the thyroid scan
how to treat graves disease
symptomatic treatment reduce T4 production radioactive iodine ant-thyroid drugs iodinated contrast agents surgery
what are you going to want to use for symptomatic treatments for graves disease
beta blocker to relieves tachycardia, tremor
propanolol
atenolol
How does radioactive iodine work to treat graves disease
destroys thyroid gland so lifelong replacement of thyroid hormone
In adenoma/toxic nodules- the adenomas take up the iodine, destroying it and leaving the normal gland tissue intact
when is the use of radioactive iodine contraindicated
pregnant women because of risk of fetus developing hypothyroidism
how do antithyroid drugs work
interferes with the production of T4
does not permanently damage thyroid
lower chance of post treatment
When is methimazole preferred
second line therapy for pregnant/ breastfeeding women
when to use PTU
in pregnancy and breastfeeding
how do iodinated contrast agents like iopnanoic acid or ipondate sodium work
temprorary tx for thyrotoxicosis
bloack conversion of T4 to T3
NOT USED FOR DEFINITIVE LONG TERM TX
when should surgery be used to treat hyperthyroidism
pts who fail medication and RAI with large goiters compromising airway
pts are treated with antithyroid drug prior to surgery to obtain euthyroid state
what are complications of thyroid surgery
recurrent laryngeal nerve paralysis or hypoparathyroidism
what is the treatment of choice for single toxic adeoma
RAI
surgical resection
what is the treatment for toxic multinodular goiter
medical tx for symptomatic tx to normalize thyroid function
followed by surgery which is the definitive treatment
how do you treat lymphocytic thyroiditis
improves over weeks on own
symptomatic treatment with beta blocker
what is the treatment for De Quervain thyroiditis
will subside spontaneously with in week to months
short course of NSAID of steriods
ANTI THYROID medis ineffective
what triggers thyroid storm
stressfull illness, thyroid surgery or RAI
what are signs and symptoms of thyroid storm
marked delirium
severe tachycardia, vomiting, diarrhea, dehydration and very high fever
what is the goal of treatment for thyroid storm
induce a euthyroid state
anti-thyroid drugs, ipodate sodium, iodine tx, propanolol, hydrocortisone then followed by radioactive iodine ablation or surgery
the risk of malignancy of non-toxic thyroid adenomas and multinodular goiters are higher in which of the following patients?
hx of head and neck radiation total body radiation for bone marrow transplant FH of thyroid cancer hoarsness vocal cord paralysis thyroid nodule
what are signs and symptoms of non-toxic thyroid adenomas mutinodular goiters
cosmetically embarrassing
cause discomfort and dyphagia
cause dyspnea d/t tracheal compression
what is the labs you want to order for a patient with a thyroid nodule
serum TSH
antithyroperoxidase Ab and antithyroglobulin Ab
what imaging is the initial test of choice for nodules
ultrasound- this measures the size and if there is multinodular goiter present
what increases the risk of the nodule being malignant
irregular or indistinct margins, greater than 1cm
what is the best method to determine if a nodule id benign or malignant
fine needle aspiration or biopsy done with US guidance
what is done to nodules including benign
monitoring with regular periodic palpation and US 6 months and re-biopsied if growth occurs
when is levothyroxine use for non-toxic thyroid adenomas
for larger benign nodules >2cm
when is the use of levothyroxine contraindicated
pts with cardiac disease
surgery is required for all types of what kind of nodules
malignant
what is the most common malignancy of endocrine system
thyroid cancer
Who is most at risk for thyroid cancer
increased incidence with age
more likely in females than males but males have a worse prognosis
what are risk factors for thyroid cancer
head and neck radiation bilateral disease nodule>4cm iodine deficiency FH of thyroid cancer hoarse voice nodule fixed to other structures lymph involvement
what is the most common type of thyroid cancer
papillary presents with single nodule related to childhood history of radiation genetics lest agressive
what is the second most common type of thyroid cancer
follicular
more aggressive than papillary
due to gene mutations or translocation
what makes up about 3% of thyroid cancers
medullary
1/3 sporadic
1/3 familial
1/3 associated with MEN type2
what makes up 2% of thyroid cancer
anaplastic
present in older pts
most aggressive
due to gene mutations
what are signs and symptoms of thyroid cancer
palpable firm non-tender nodule
most are asymptomatic some can cause neck discomfort
how would a thyroid cancer be diagnosed
FNA biopsy with cytology testing
what is usually high in metastatic disease
high serum thyroglobulin
what is elevated with medullary carcinoma
serum calcitonin
carcinoembryonic antigen
What can you use for imaging
U/S help localize and measure
RAI scan-post
thyroidectomy
CT/MRI-located metastasis
what is the first line treatment for thyroid cancer
surgery
RAI therapy
radiation therapy
thyroid hormone supplementation
