Term
| what is the half life of T3/4? |
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Definition
| T3: about 1 day, T4: about 7 days |
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Term
| what is a delphian lymph node? |
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Definition
| a lymph node which contains metastatic thyroid CA |
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Term
| what is a thyroglossal duct cyst? |
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Definition
| a cyst which may mimic a thyroid nodule, can be congenital |
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Term
| what is pemberton's sign? |
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Definition
| if a pt has an enlarged thyroid gland it can float into the sternal notch on hyperextension of the neck = asphyxiation |
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Term
| who is at risk for thyroid disease and needs to be screened? |
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Definition
| pts with: autoimmune disease (DM, etc), a 1st degree relative w/thyroid disease, hx of surgical/radioactive thyroid tissue destruction, hx of amiodarone tx, > 60 y/o, pts on lithium, female psych pts, and bipolar pts w/rapid cycling |
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Term
| what 2 lab tests can dx most thyroid dysfunctions? |
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Definition
| TSH (normal levels ~.4 to 4) and free T4 |
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Term
| what drugs decrease TSH secretion? |
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Definition
| dopamine, glucocorticoids, and octreotide |
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Term
| what drugs decrease thyroid hormone secretion? |
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Definition
| lithium, iodide, and amiodarone |
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Term
| what drugs increase thyroid hormone secretion? |
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Definition
|
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Term
| what drugs decrease T4 absorption? |
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Definition
| colestipol, cholestyramine, aluminum hydroxide, ferrous sulfate, and sucralfate |
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Term
| what conditions increase TBG binding? |
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Definition
| pregnancy, estrogen therapy, OCPs, acute intermittent porphyria, hypothyroidism |
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Term
| what conditions decrease TBG binding? |
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Definition
| nephrotic syndrome, androgens, marked hyperproteinemia, acromegaly, and dilantin |
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Term
| what are the different classifications of thyroiditis? |
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Definition
| infectious (suppurative/nonsuppurative - uncommon), subacute nonsuppurative thyroiditis, autoimmune thyroiditis (hashimotos, chronic thyroiditis, lymphocytic thyroiditis of adolescence, atrophic asymptomatic, and idiopathic myxedema), riedel's struma (fibrosis), and misc (radiation, traumatic, sarcoidosis, amyloidosis) |
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Term
| what characterizes adult hypothyroidism? |
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Definition
| insidious development, tiredness, lethargy, and wt gain (3-4 lbs) |
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Term
| what are the classifications of the causes of hypothyroidism? |
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Definition
| thyroprivic (problem w/thyroid: postablative/idiopathic/aplastic/dysplastic), trophoprivic (problem w/pituitary: sheehan's, infiltrative disorders), and goitrous (problem w/thyroid+goiter: hashimotos, endemic iodine deficiency, antithyroid agents, heritable biosynthetic defects, and peripheral resistance to TH) |
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Term
| what is the most common acquired cause of hypothyroidism? most common endemic cause of hypothyroidism |
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Definition
| acquired: postablative hypothyroidism and endemic: hashimotos |
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Term
| what is another name for hashimotos? |
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Definition
|
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Term
| how does hypothyroidism present on a physical exam? |
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Definition
| coarse scalp hair, thinning eyebrows, macroglossia, yellowed skin due to vit A accumulation, and possible thyroidectomy scar. |
|
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Term
| what are the 2 major autoimmune Ab produced in hashimotos? |
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Definition
| antimicrosomal/thyroid peroxidase (100%) and antithyroglobulin (85%). assays for these Ab as well as free T4 and TSH are used to dx hashimotos. |
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Term
| what characterizes the effect of hypothyroidism on the CV system? |
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Definition
| increased peripheral resistance (evidenced by increased diastolic pressure), arrhythmia/bradycardia, and "myxedema heart" (pericardial effusion) |
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Term
| what characterizes the effect of hypothyroidism on the respiratory system? |
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Definition
| pleural effusion and CO2 retention w/no hx of COPD |
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Term
| what characterizes the effect of hypothyroidism on the GI/alimentary system? |
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Definition
| achlorhydria, constipation, wt gain, and gastric atrophy (pernicious anemia) |
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Term
| what characterizes the effect of hypothyroidism on the neurologic system? |
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Definition
| h/a, somnolence, and lethargy |
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Term
| what characterizes the effect of hypothyroidism on the musculatory system? |
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Definition
| proximal myopathy (mucopolysaccharide deposition), kocher-debre/semelaingne (muscle atrophy in the newborn), and hoffman's syndrome (weakness due to mucopolysaccharide deposition) |
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Term
|
Definition
| fluid is drawn into subcutaneous tissue due to mucopolysaccharide deposition which increases osmotic gradients = non-pitting edema. |
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Term
| what are the dermatologic manifestations of hypothyroidism? |
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Definition
| boggy/nonpitting edema, dry skin and hyperkeratosis |
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Term
| what characterizes the effect of hypothyroidism on the reproductive system? |
|
Definition
| decreased libido and fertility |
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|
Term
| what can happen if infant hypothyroidism (cretinism) isn't diagnosed and treated? |
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Definition
| retardation of mental development and growth |
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Term
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Definition
| a severe form of hypothyroidism w/profound *hypothermia (reduced core temp) which often presents in the winter months after gradual progression. these pts are often hypoventilated, may develop pneumonia, and can end up on ventilators for months. myxedema coma can be lethal and is treated w/IV L-thyroxine+cortisol. |
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Term
| what is tx for hypothyroidism w/o myxedema coma? |
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Definition
| get pts on a maintenance dose of TH and monitor TSH levels - may need to start on low dose for elderly pts. early improvement consists of loss of edema, diuresis, improved hoarseness, and better well-being. |
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Term
| what conditions may cause a goiter? what is the risk of removing them? |
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Definition
| goiters can be seen in pts w/euthyroid, hyperthyroid or hypothyroid and may not need to be removed as they grow to provide part of the trachea's support. |
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Term
|
Definition
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|
Term
| what is the most common form of hyperthyroidism? |
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Definition
| graves disease, an autoimmune disease similar to hashimotos, but w/different Ab: thyroid stimulating immunoglobulin (TSI, which acts like TSH) |
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Term
| can a hyperfunctioning adenoma cause hyperthyroidism? |
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Definition
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|
Term
| can a toxic or nodular goiter cause hyperthyroidism? |
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Definition
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Term
| what is subacute thyroiditis? |
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Definition
| subacute thyroiditis will generally cause hypothyroidism, but it can also cause an initial phase of hyperthyroidism (TH is released due to infection - depletes gland) |
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|
Term
| what is thyrotoxicosis factitia? |
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Definition
| thyroid disease due to medication (sometimes self-administered) |
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|
Term
| what characterizes graves disease? |
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Definition
| graves disease: autoimmune disorder marked by hyperthyroidism (TSH-like autoantibodies), symmetrical *diffuse goiter (increased vascularity causes an audible bruit) *pretibial edema/hyperpigmentation, and exophthalmos (levator palpebrae constantly contracted due to sympathetic tone: bi-ocular stare). |
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Term
| what are the signs/symptoms of hyperthyroidism? |
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Definition
| tachycardia, palpitations, exercise intolerance, rapid/bounding pulses, wide pulse pressure (like a BP: 160/20), fatigue, hyperactive precordium, heat intolerance, large appetite, and wt loss (includes muscle mass) |
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Term
| what are the cardiac manifestations of hyperthyroidism? |
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Definition
| classic: *atrial fibrillation, heat intolerance, irritability, nervousness, emotional liability, muscle weakness, menstrual abnormalities, and weight loss. a *means-lerman scratch may be auscultated which is rubbing of the pericardium against the pleura in the context of hyperdynamic circulation and tachycardia. heart failure is possible b/c the hyperthyroid heart is performing at max capacity. HTN featuring high systolic pressure and a wide pulse pressure. systemic vascular resistance is usually reduced. |
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Term
| can onycholysis be a sign of hyperthyroidism? |
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Definition
| yes - due to irregular growth |
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|
Term
| what is tx for hyperthyroidism? |
|
Definition
| anti-thyroid meds such as propylthiouracil, beta blockers, and possibly I-131 (can create hypothyroidism) |
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