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67 Cards in this Set
- Front
- Back
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What is the name of the ligament that connects the thyroid lobes to the trachea?
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Berry's ligament (lateral suspensory ligament)
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What do the C-cells do in the thyroid?
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aka parafollicular cells secrete calcitonin (dec serum Ca by inhibiting gut absorption & inhibits osteoclast (crash) activity & inhibits phosphate & Ca reabsorption in kidneys)
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What does calcitonin do?
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dec serum Ca by inhibiting gut absorption & inhibits osteoclast (crash) activity & inhibits phosphate & Ca reabsorption in kidneys
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Thyroid derived embryologically from?
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endoderm btwn 1st and 2nd brachial arch
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Where does the vascular supply of the superior thyroid artery come from?
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ECA -> superior thyroid a. -> superior pole of thyroid
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Where does vascular supply of inferior thyroid artery come from?
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SCA -> thyrocervical trunk -> inf thyroid artery -> lateral lobes & inf/sup parathyroid arteries
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Where does vascular supply of inf/sup parathyroid arteries arise from?
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SCA -> thyrocervical trunk -> inf thyroid artery -> lateral lobes & inf/sup parathyroid arteries
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What is the innominate artery?
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Brachiocephalic artery (R)
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Where does thyroid isthmus get its blood supply from?
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aortic arch or innominate -> thyroidea ima artery
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Where do the lymphatics of the isthmus & median lateral lobes drain to (2)?
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Delphian (prelaryngeal) & digastric nodes
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Where do the lymphatics of the inferior lateral lobes drain to (2)?
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Pretracheal & cervical nodes
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What is the loop of Galen?
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sensory branch of RLN joins internal branch of SLN
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What does the SLN innervate (ext/int br)? Proximal to which artery?
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Parallels superior thyroid artery; external branch innervates cricothyroid muscle; internal branch pierces thyrohyoid membrane innervates sensory larynx
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Damage to SLN results in?
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change in pitch, inability to make explosive sounds
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What does the RLN innervate?
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the laryngeal muscles - posterior cricoarytenoid, lateral CA, artytenoid, thyroaretenoid.
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Damage to the RLN causes?
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Abduction of the vocal cord. Aphonia.
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Sensory innervation of larynx above vocal folds is? below vocal folds?
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above = SLN. below = RLN
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Describe course of RLN once starts ascending. (what arteries close to, relative to thyroid gland, where enters larynx?)
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Tracheoesophageal groove, inf thyroid artery, middle 1/3 of thyroid gland, crosses posteriorly or superficially to inf thyroid artery. superiorly and medial along posterior thyroid capsule. enters larynx btwn cricoid cartilage and inferior cornu of thyroid cartilage
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Goal TSH levels with Synthroid (to suppress further tumor growth)?
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TSH = 0.1-0.2
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The Wolff-Chaikoff Effect occurs when iodine is given; what is it?
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inhibits thyroid hormone
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Thyroid storm; mainstay of treatment to treat hemodynamic effects?
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Beta blockers. Esmolol (short-acting) & Metoprolol. Also blocks conversion of T4->T3
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FNA of thyroid nodule shows benign, how long before consider next FNA (esp if change in size)?
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Can observe. Otherwise repeat FNA in 6-12mo.
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FNA shows uniform follicular epithelium and abundant colloid; most likely dx?
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nodular or adenomatous GOITER
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FNA shows follicular cells; next step in mgmt?
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Hemithyroidectomy b/c cannot tell whether benign or malignant (extracapsular spread, lymph inv, vascular inv, metastasis)
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FNA shows Hurthle cells; next step in mgmt?
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Hemithyroidectomy b/c cannot tell whether benign or malignant (extracapsular spread, lymph inv, vascular inv, metastasis). can also be hashimoto's thyroiditis
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FNA shows amyloid deposits (stained with Congo red); ML dx?
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Medullary carcinoma
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Undifferentiated cells; ML dx?
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Anaplastic carcinoma.
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Do "cold" or "hot" thyroid nodules have higher rates of malignancy?
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"Cold" - 5%-20%; "hot" only 4%
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Radionucleotides: 99m Tc pertechnetate, 131I, 123I; which one is used for ablation? which one is used for imaging?
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99m Tc pertechnetate - imaging; 131I - ablation
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"Hot" thyroid nodule likely not malignant; if hyperthyroidism, what is preferred tx?
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radioactive iodine
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Thyroid cancer staging: I-IV
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I - thyroid only. II: nonfixed cervical node; III: fixed cervical node; IV: metastasis
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Man with h/o intestinal polyps and new thryoid mass; must be concerned for?
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papillary cancer with Gardner's syndrome
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Prognosis for papillary carcinoma is 95% 5-year survival; Poor prognostic indicators include tumors >__cm or extracapsular spread. Do cervical mets affect survival?
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>1.5cm. Cervical mets have increased cervical recurrence rates without affecting survival.
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After total thyroidectomy for papillary carcinoma, what should the next step in treatment be? When? TSH levels?
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Radioactive Iodine Uptake study( RAIU) and thyroid radionucleotide scan. if residual dz, 131Iodine 6w; hypothyroid state TSH>50,
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How frequently should papillary thyroid cancer pts be monitored after initial surgical/radiation tx? What imaging is used to monitor?
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whole body radioactive scans in 6-12mo then in ~2y; serum thyroglobulin
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How do follicular thyroid carcinomas spread: hematogenous or lymphatic?
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Hematogenous with distant metastasis
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5-year prognosis of follicular thyroid carcinoma? If distant mets?
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70%-85% worse with angioinvasion or extracapsular spread. 20% with distant mets
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Hurthle cell tumors are a variant of follicular cell carcinoma; better or worse prognosis? Poor uptake of radioactive iodine.
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Worse 50% 5-year survival compared to 70%-85%
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Thyroid carcinoma with +Ret-3 oncogene mutation; which type?
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Medullary thyroid carcinoma
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Medullary thyroid carcinoma: does unilateral or bilateral have worse prognosis?
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Unilateral
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Tx for unilateral medullary thyroid carcinoma? Prognosis.
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total thyroidectomy with elective MRND; Prognosis 50%-80% (worse if unilateral, young pt, mets)
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Can radioactive iodine be used for medullary thyroid carcinoma?
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NO, parafollicular (C-cells) do not take up I131.
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Tx for unilateral anaplastic carcinoma?
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no adequate therapy, uniformly fatal, trach & consider CXRT
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Most common lymphoma of thyroid? Associated with chronic lymphocytic thyroiditis & Hashimoto thyroiditis
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non-Hodgkin B-cell lymphoma
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MEN I - composed of?
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PPP - Parathyroid hyperplasia; Pancreatic tumors (insulinomas, gastrinomas), Pituitary adenomas
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MEN III - composed of?
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MMMP - Marfanoid habitus, Mucosal neuromas, Medullary thyroid carcinoma, Pheo
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tx of non-Hodgkin lymphoma of thyroid: XRT, Chemo, or CXRT?
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XRT. can consider total thyroidectomy if lymphoma contained within thyroid
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Mgmt of thyrotoxicosis (thyroid storm); fever, abd pain, psychosis, stupor? Four meds
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Propylthiouracil (PTU), inorganic iodine, propranolol, corticosteroids
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MCC of goiter worldwide is iodine deficiency (90%); what is MCC of goiter in US?
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Hashimoto's thyroiditis
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Mechanism for Grave's disease causing hyperthyroidism?
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Thyroid-stimulating immunoglobulins (TSIs) -> stim glandular hyperplasia via TSH receptor -> T3 + T4 + goiter
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Why do Grave's pts have exophthalmos?
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Autoimmune depositions in extraocular muslces
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Treatment for Grave's? When is surgery indicated?
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Radioactive Iodine I131
Also: PTU, methimazole, propranolol; Surgery for failed medical therapy, pregancy, cold nodule |
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MCC of painful thyroid?
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Subacute Granulomatous Thyroiditis (de Quervain's); ?caused by viral etiology?
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Subacute granulomatous thyroiditis; hyper- or hypothyroid? Painful. tx?
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Transient hyperthyroid then hypothyroid.
Tx:NSAIDs, poss corticosteroids |
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Mechanism for hypothyroidism in Hashimoto's thyroiditis? Painless.
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antithyroglobulin & antimicrosomal ab -> anti-TSH receptor -> transient hyper- then hypothyroid
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When surgery for Hashimoto thyroiditis?
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compressive sxs, pregnancy, cold nodule
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"Rock-hard" thyroid produces local pressure and hypothyroidism; dx?
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Riedel's thyroiditis - fibrosis; hypothyroid. tx:hormone replacement
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Where are the superior parathyroids usually located in relation to the intersection btwn the RLN and inferior thyroid artery?
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1cm above the intersection (inferior thyroids usually located 1-2cm from entrance of inf thyroid art into lower thyroid pole)
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How much does each parathyroid gland weigh?
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20-40mg
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Embryologicaly; where do superior parathyroids come from? Inferior parathyroids? Thymus?
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Superior - 4th dorsal branchial pouch; Inferior & thymus - 3rd dorsal branchial pouch;
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Inferior thyroid artery arises from? Superior thyroid artery?
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Inferior thyroid artery -> inf/sup parathyroid arteries; Superior thryoid artery -> occ sup parathyroid artery
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In acidosis, is there more or less ionized calcium?
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More ionized calcium b/c H+ competes with Ca on albumin
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In serum, how is calcium stored?
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46% Ionized; 46% Albumin; 8% complexed to anions
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PTH stim activation of VitD via 25-hydroxylation in liver & 1-hydroxylation in kidney; what action does VitD have on calcium and phosphate?
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Inc intestinal absorption of calcium and phosphate (also minor kidney absorption & bone reabsorption)
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What is effect of parathyroid hormone on serum calcium & phosphate?
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inc serum calcium (osteoclast, absorption, VitD), dec serum phosphate (excretion)
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Hypercalcemia causes, bone & joint pain (osteitis fibrosa cystica), depression, constipation, pancreatitis, nephrolithiasis, and what EKG abnormality?
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shortened QT interval (& heart block)
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Initial step in patient with symptomatic hypercalcemia? Medications (3)? Others include steroids, plicamycin, Cinacalcet, phosphate salts.
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IV hydration unless renal failure; 1.Bisphosphonates (dec osteoclast activity); 2.Loop diuretics; 3.Calcitonin (dec bone resorption, inc excretion)
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