THYROIDITIS Flashcards
what is thyroiditis?
general term that refers to “inflammation of the thyroid gland”
what are the 2 main etiologies of thyroiditis?
- autoimmune thyroiditis (hashimoto thyroiditis)
- painful subacute thyroiditis
what is hashimoto thyroiditis?
aka chronic lymphocytic thyroiditis
most common form of thyroiditis
it is an autoimmune thyroid disease resulting in destruction and failure of thyroid glans
whats the epidemiology of hashimotos thyroiditis?
age of onset between 30-50
more common in females
exact trigger unknown although genetic and environmental factors play a role
what genetic mutation (risk factor) is associated with hashimoto thyroiditis?
mutation in HLA-DR3 and DR5 genes
hashimoto thyroiditis has increased incidence in patients with what other 2 disease states (risk factor)?
downs syndrome
turners syndrome
what suggest genetic susceptibility of hashimoto thyroiditis (Risk)?
disease clusters found in families suggest genetic susceptibility
what is the first step in hashimoto thyroiditis pathogenesis?
autoimmune destruction is initiated; progressive depletion of thyroid epithelial cells
what is the second step in hashimoto thyroiditis pathogenesis?
and what mediated this step?
thyroid cell destruction mediated by:
1. CD8+ cytotoxic cells
2. local production of cytokines:
what is the third step in hashimoto thyroiditis pathogenesis?
antibodies made to thyroglobulin (tg) and thyroid peroxidase (tpo)
what is the 4th step in hashimoto thyroiditis pathogenesis?
lymphocytic infiltration and fibrosis of thyroid cells -> follicles are disrupted and released of stored thyroid hormones:
1. transient increase of thyroxine T4 and
triidothyronine T3
2. compensatory decrease thyroid-stim hormone follows… T3/T4 stores gradually decline
3. end result: increase in TSH+ hypothyroidism (often permanent)
with hypothyroidism what are you at an increased risk of having?
- developing other autoimmune diseases
- b-cell lymphoma of thyroid gland d/t chronic inflammation
what is the triphasic clinical course of hypothyroidism?
- hashitoxicosis- initial transient hyperthyroidism
- subclinical hypothyroidism
- overt hypothyroidism
what are the common signs of hypothyroidism?
not talking about cold intolerance
- +/- goiter
- dry, coarse skin; alopecia; cool extremities
- puffy face, hands and feet (nonpitting edema/myxedema), bradycardia
hypothyroidism common symptoms:
- hoarse voice, impaired hearing
- constipation
- difficult concentrating/ poor memory
- fatigue, cold intolerance, weight gain
- hair loss, dry skin
- paresthesia
- menstrual irregularities (menorrhagia then oligomenorrhea or amenorrhea)
what are the thyroid levels in hashitoxicosis phase?
low TSH + increased T3/T4
what are the thyroid levels in subclinical hypothyroidism phase?
increased TSH and normal T3/T4
what are the thyroid levels in overt hypothyroidism phase?
increased TSH + decreased T3/T4
what other level is increased in 90% of hypothyroidism cases and is a good diagnostic indicator?
increased TPO (thyroid peroxidase)
high TPO levels predict progression to symptomatic hypothyroidism
what level is increased in 40% of hypothyroidism cases?
thyroglobulin antibodies
what is an incredible diagnostic test for hypothyroidism?
thyroid US
- helps to differentiate between thyroiditis, multinodular goiter, thyroid nodules, or malignancy
radioactive iodine uptake diagnostic test (RAI U) is an important test. if there is low uptake what does this mean?
cold thyroid
when would you do a FNA?
when there is a dominant nodule or suspicion of malignancy
what is the purpose of a thyroid uptake scan?
it is a radiologic diagnostic tool used to determine the thyroid fxn and pathology
what does a thyroid uptake scan use?
radioactive iodine
what does a graves disease thyroid uptake scan look like?
diffuse increased uptake in both thyroid lobes -looks hella black because shit ton uptake
what does a toxic goiter look like on a thyroid uptake scan?
“hot” and “cold” areas of uneven uptake
what does a toxic adenoma look like on a thyroid uptake scan?
increased uptake in the single nodule with suppression of surrounding thyroid
what does thyroiditis look like on a thyroid uptake scan?
decreased or absent uptake (all grey)
what is hashitoxicosis treatment?
- antithyroid medication should NOT BE USED
- non-specific beta-blockers to block peripheral conversion of T4 to T3
what is overt hypothyroidism treatment?
- levothyroxine- synthetic form of T4 thats peripherally converted to T3
- 1.6 mcg or 25 mcg in the elderly
- adj. dose by 12.5 or 25 mcg every 4-6 weeks until clinically euthroid; can also reduce goiter size
- Goal: TSH of 1-2
how do you treat a patient with elevated TPO ab levels and subclinical hypothyroidism?
- levothyroxine 25-50 mcg PO daily
- adj. dose by 12.5 or 25 mcg every 4-6 weeks until clinically euthroid
what does painful subacute thyroiditis often follow?
a URI-> triggers inflammatory destruction of thyroid follicles
what is painful subacute thyroiditis?
transient thyrotoxic state characterized by anterior neck pain
what do 1/3 of patients who don’t recvoer from painful subacute thyroiditis turn into?
overt hypothyroidism over a 10- year period
what is the initial clinical presentation of painful subacute thyroiditis?
- neck pain in the area of the thyroid (cardinal feature) that may radiate to the jaw
- diffuse thyroid enlargement (goiter)
- dysphagia
- increased sweating
- tremors/ weight loss
- fever/tachycardia
(notice how all there are hyperthyroid sx)
what are the characteristics of the thyrotoxic phase of painful subacute thyroiditis?
lasts 4-8 weeks
decreased TSH
initially increase in T4/T3 9T4>T3- transient hyperthyroidism is d/t passive release of stored thyroid hormone
increased ESR and CRP
thyroid scan with radioactive iodine uptake shows low iodine uptake
what are the characteristics of the hypothyroid phase?
variable length
increased TSH and decreased T4 and T3
in most cases, what is the thyroid able to do as far as “treatment”?
it is able to spontaneously resume normal thyroid production after some months in most cases
whats the tx option for patients with significant hyperthyroid symptoms?
beta blockers
in patients who have clear signs of hypothyroidism or are symptomatic, what is the treatment?
thyroid hormone supplementation (levothyroxine)
what is the tx for relief of thyroid pain?
first line: aspirin 2600 mcg/ day; ibuprofen 3200 mcg/day
if there is no improvement of neck pain after 4 days or patient has severe neck pain what is the tx?
corticosteroids 40 mg/ x5-7 days then slowly tapered over 30 days
