Lecture 46 April 11th-endocrine

1DDX: LECTURE 46 – APRIL 11TH, 2007 Endocrine (2), Thyroid Page 1 When auscultating thyroid, can hear venous hums and sounds from carotid. This is normal. 1 tsp of iodized salt contains 400 micrograms of iodine. RDA is 150. Sea salt has less iodine than iodized table salt. Small amounts of iodine in dairy and eggs. Goitrogens: Block uptake of iodine by thyroid tissue. In raw form, can exacerbate hyperthyroidism. Iodine supplements can cause hyper or ultimately hypothyroidism Lymphadenopathy: cervical and brachial Maroni sign: redness/itchiness over thyroid due to lymphocyte proliferation Exophthalmos in Graves’ Systolic bruit: intermittent: thyroid condition. Constant bruit? False positive: Atherosclerosis or stenosis of carotid artery. Also, venous hums sounds like bruit d/t venous compression. Enlarged thyroid can compress jugular vein (JVP), carotid, Vagus (hoarseness), trachea (sob), esophagus (dysphagia) In hypothyroidism, deep tendon reflexes are diminished.

Acropachy: clubbing of the fingers associated with hypothyroidism (Graves’) Euthyroid: structural change, but no change in function. Don’t see any symptoms in these patients. Hypo: structure is same, but change in function Hyper: change in both structure and function. Non-thyroid S/sx: don’t originate in thyroid specifically. Exposure to radiation: in neck area? Page 2 Rare for problem to come from pituitary or hypothalamus (secondary or tertiary). Rare to have thyroid insensitivity to TSH. Measure free T3/T4: up to 90% of T4 is protein bound. T3 is 75% bound. Liver and chronic kidney disease affects albumin and changes the binding of T3 and T4. FYI: Drugs that increase TSH: lithium, potassium iodide Drugs that decrease TSH: chronic aspirin use, dopamine, heparin, steroids Pregnancy and estrogen use will increase binding capacity. Chronic testosterone use decreases binding capacity of globulins Drugs that increase free T3: estrogen, methodone, BCP, androgens, anabolic steroids, high dose salicylates. (Test: big ideas, red flags. Exam questions will ask to DDx based on symptoms. Not tricky!) Thyroid scan: for hot/cold thyroid. Inject iodine. “Hot thyroid” takes up iodine and functions. Cold does not take up iodine therefore non-functional. Increased likelihood of cancer. Thyroid ultrasound: external. DDX fluid filled from solid nodules. Used to detect nodules. DDX LECTURE 46, APRIL 11TH, 2007 – PAGE 1

(cross off RAIU, Iodine skin test from notes) BMR: baseline body temperature over a month. 36.5-37 normal 36-36.5: subclinical hypothyroidism Below 36: will also see a change in labs. Calcitonin (HCT=human calcitonin): Medullary carcinoma: malignant, aggressive. If MEN, or family history of medullary carcinoma, do test. HCT=human calcitonin. Congenital abnormalities: Whatever affects thyroid will also affect heterotropic thyroid tissue. Lateral aberrant thyroid: tissue on lateral wings (can be metastasis or ectopic thyroid) Non-toxic goiter: Increase in size of follicular cells, usually due to hypothyroidism, then it increases in size and becomes euthyroid. Note how thyroid will feel: With goiter, it will become nodular, but not cancerous. Can happen after period of emotional stress. Malignancies are more common in men than women. Every other thyroid condition has a higher incidence in women. Patient may present with swollen neck, sore throat, swollen lymph nodes. Under “lab findings” cross off reference to RAIU Page 3 Euthyroid: multinodular (hyperthyroidism) Treatment: TSH suppression using thyroid hormone may not work after 50 because nodules, functional exogenous TSH will increase their function. Slide 2: cross off reference to RAIU Euthyroid sick syndrome Slide 4: Cirrhosis may be due to alcoholism Lab findings: Serum cortisol elevated: ESR may be elevated. Serum cortisol elevated Page 4 Slide 1 under Nutrition: should say T4T3 conversion. Congenital cretinism: endemic due to iodine deficiency. “dysgenesis” refers to genetic problem. Hashimoto’s thyroiditis is most common form. Because it is an autoimmune process, there is a proliferative lymphocytic infiltration: lymphedema Circulating antibodies to thyroid antigen Serum cholesterol is high in primary hypothyroidism. Free T4 is normal in beginning stages of Hashimoto’s. Myxedema: due to capillary vasoconstriction Problems with nervous system from nerve compression due to lymphedema Increase triglycerides, increased cholesterol. Reproductive problems due to low BMR. Page 5 Primary hypothyroidism, non-goitrous Very similar to euthyroid. Due to cirrhosis, MI, surgery. Sub-acute: no autoimmune: no lymphocytic edema, therefore, no symptoms to do with edema. Acute inflammatory thyroid caused by a virus: antecedent URTI, sore throat. Lab findings: high erythrocyte sedimentation rate. Initial transient hyperthyroid. Self-limited hyperthyroid phase, then transient hypothyroidism and eventual recovery. DDX LECTURE 46, APRIL 11TH, 2007 – PAGE 2

Silent thyroiditis: euthyroid to start. Post-partum. Thyroid antibodies, WBC count and ESR are normal. Page 6 Graves’ disease: No nodules, exophthalmus due to edema.

Proptosis=exophthalmus. Lid retraction, lose definition of the upper lid. Eyelashes can scratch eye. Palpable, audible bruit over thyroid in Graves’ Can spontaneously remit. If pretibial myxedema gets really bad, they get paraesthesia, then can look like other diseases. Plummer-vinson syndrome: Occurs in elderly because it takes time for toxic multinodular goiter to result. Page 7 Anti-thyroid meds don’t work well in elderly. Often patient describes “hoarseness” as sore throat. Red flag. Plummer-Vinson: See areas of atrophy in thyroid. Surgery indicated when issues of compression: trachea, esophagus, laryngeal nerve (hoarseness), carotid artery, jugular vein. Toxic adenoma: Same symptoms as toxic multinodular goiter. Can’t DDX on physical examination. Need nuclear scan. Hypersecretion of TSH: Secondary: see high TSH, high T3/T4. Dexamethasone (cold medication) contains iodine. Thyroid storm? Refer to hospital. Life-threatening. DDX extreme anxiety attack. Page 8 Cold nodules, because tissue has de-differentiated. Hard, fixed, non0tendar, non-palpable edges. Cervical Lymphadenopathy Follicular adenoma: Do every test in the book when history of medullary thyroid carcinoma. Malignant neoplasms: just skim over. Mets go to the bones of the shoulder (slide 5): red flag. Page 9 Follow people with family history of MEN and medullary carcinoma.

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