Thyroid disorder Flashcards
What does high iodine levels do to TH?
Wolff-Chaikoff: Thyroid gets stunned and stops production temporarily as a protective behavior. Begins again after a few days. #: seen with cardiac catheterization and CT with contrast.
Jod-Basedow effect: overproduction of thyroid hormone causing overt hyperthyroidism in the presence of large amounts of iodine in persons who fail to manifest the Wolff-Chaikoff effect.
What happens to TH levels in pregnancy?
Change- non thyroid disease can adjust appropriately, otherwise increase hormone drug
What is the test of choice to screen for abnormal thyroid function?
TSH
When does the fetus start making its own TH? What happens before that?
week 10/11. Before, TH crosses placenta and the placenta regulates how much TH baby gets
TH affect on pulmonary system?
modulates the way the brain responds to CO2. Doesnt respond to hypercapnea- seen in long standing disease. Would result in respiratory acidosis?
T3 functions (4 Bs)#
B: brain maturation
B: bone growth
B: beta adrenergic effects
B: basal metabolic rate increases
Thyroid hormone effects on CV system.
Increased B1 receptors in the heart so there is more responsiveness to epinephrine. #: increased contractility, SV, HR--> inceased CO
Thyroid hormone effects on bones#
TH facilitates growth by stimulating GH gene expression in somatotrophs of the anterior pituitary. TH also stimulates calcification and closure of cartilaginous plates throughout the body.
Effects of thyroid hormone on GI?
Hyper: diarrhea
Hypo: constipation
Effect of thyroid hormone on lipids and carbs?
Lowers cholesterol . Stimulates fuel mobilization and catabolism
Explain hypothyroidism in babies and why its bad.
: Cretinism: mental retardation, short stature, coarse features, umbilical hernia.
Usually do to agenesis. Worldwide problem due to iodine deficiency. Preventable. Bone age, height, and mental age won’t normalize if not treated in first few days.
Symptoms of hypothyroidism
fatigue, weakness, dry skin, feeling cold, hair loss, memory, constipation, weight gain with poor appetite, menorrhagia,
Signs of hypothyroidism
also goiter
dry, coarse skin, puffy face, hands, and feet, diffuse allopecia, bradycardia, peripheral edema, carpal tunnel syndrome, serous cavity effusions, delayed tendon reflex relaxation.
Symptoms of hyperthyroidism
fatigue, weakness, hyperactivity, irritability, dysphoria, heat intolerance, sweating, palpitations, weight loss with increased appetite, diarrhea, oligomenorrhea, loss of libido
Signs of hyperthyroidism
tachycardia, a fib in elderly, goiter, tremor, warm, moist skin, muscle weakness, proximal myopathy, lid retraction
T or F. Goiters are always associated with elevated TH levels.
False
Clinical manifestations of Grave’s disease #
diffuse, nontender goiter with or without a bruit.
Infiltrative opthalmopathy, pretibial myxedema.
What type of hypersensitivity reaction is Graves?#
Type 2
Oncholysis is associated with _____.
Hyperthyroidism
When is TSH NOT a reliable test?
Hyperthyroidism (you would expect a low TSH unless…) TSH secreting pituitary adenoma, isolated pituitary resistance to TH
Hypothyroidism (would expect HIGH) central hypothyroidism
Euthyroid- systemic illness, generalized resistance to thyroid hormone, assay interference
What is thyroid storm/thyrotoxicosis?#
life-threatening, presents with high fever, tachyarrhythmia, psychosis, confusion, diarrhea, and liver dysfunction. Manage with ICU support, antithyroid meds, and B blockers.
Dont wait for test results before starting therapy!!!!!!
Which TH hormone level will respond quicker to changes?
T3
What is a toxic multinodular goiter?#
hyperfunctioning areas that make Increase T3/T4 and patchy uptake on thyroid scan. Due to a mutation in TSH receptor and is more common in elderly. Presents like Graves but less sever.
PAINLESS goiter.
8 endogenous causes of hyperthyroidism
Graves, toxic multinodular goiter, toxic adenoma, GOF TSH receptor mutation, GOF Gs (GPCR) mutation, struma ovarii, thyroiditis, secondary hyperthyroidism
What drugs can cause primary hypothryoidism?
lithium, amiodarone, interferon alpha
Etiology of primary hypothyroidism
Thyroiditis, RIA tx for Graves disease, Thyroidectomy, Excessive iodine intake, Iodine deficiency, Inborne errors of TH synthesis, Drugs (lithium, amiodarone, interferon-alpha)
Etiology of secondary hypothyroidism
destruction of pituitary gland, hypothalamic dysfunction, peripheral resistance
What might you see in an acute/subacute thyroiditis?#
Can go both ways and follows an upper respiratory illness
1. Hyperthyroidism, PAINFUL goiter, fever, elevated ESR, radiating pain to ears, neck, arm
Hypothyroidism: usually follows hyper.
2. Hypothyroidism: self-limited, may have elevated ESR, jaw pain, tender gland, granulomatous inflammation
How does Riedel’s thyroiditis present?#
Rare disease in which thyroid tissue is chronically replaced by fibrosis.
Rock-hard, fixed, PAINLESS goiter
What are causes of a painful goiter?#
Subacute thyroiditis
What are causes of a painless goiter?#
Hashimotos, graves, toxic multinodular goiter, iodine def, riedels thyroiditis
Someone comes in with a “rock hard” goiter. You should be thinking- #
Riedel’s
Risk factors for thyroid cancer
childhood radiation exposure, male, young age, family history
radiation, 45 y/o, nodule >4 cm, new or enlarging mass, male gender, hoarse voice/vocal cord paralysis, nodule fixed to adjacent structures, extra-thyroidal extension, suspected lymphnode involvement, iodine def, family history (MEN2)
