NMS Q&A Family Medicine

206 NMS Q&A Family MedicineExamination Answers1. The answer is A. The incorrect statement is that criticallymyxedematous hypothermic patients may be treatedby warm IV fluids. In fact, such aggressive address ofhypothermia may precipitate cardiovascular collapse.Warming should be accomplished with blankets. Levothyroxine400 g loading dose given IV is indicated and mayresult in improvement within hours. IV glucocorticoidmay be indicated because adrenal insufficiency may coexistwith myxedema itself. Myxedema interferes withgastrointestinal absorption of oral thyroid preparations.Thus, medications may have to be given IV. Relatively lowmaintenance IV dosage (e.g., 50 g) is selected initially inpatients with known coronary artery disease. Coexistinginfections must be treated more aggressively.2. The answer is D. 100 to 150 g daily, a relatively highlevothyroxine starting dosage, is appropriate for pregnantwomen. This addresses the facts that (a) fetuses are notthyroid sufficient until term; (b) high estrogen levels, asobtained during pregnancy, require increased dosing toachieve euthyroidism. Maternal hypothyroidism is a riskfor fetal central nervous system development in the secondtrimester, adding to the need for emphasizing adequatedosing in pregnancy. Dosages range downward innonpregnant people; for example, a starting dosage forcardiac patients is perhaps 25 g, advancing in increments.They may range upward to 250 to 300 g daily.3. The answer is E. Thyroid acropachy, an extreme andunusual manifestation of Graves disease, that is, an autoimmunedisease that includes periosteal reaction. Ophthalmopathyis the tip that Graves disease is in the picture.Multinodular goiter, while likely featuring a stare or lid lag,is not characterized by ophthalmopathy (inflammatoryexophthalmos). Paget disease manifests typical bone changeseasily seen on x-ray but not clubbing. Chronic obstructivepulmonary disease and hepatic cirrhosis are known to be associatedwith digital clubbing but without ophthalmopathy.4. The answer is B. Side effect of lithium does not have aside effect of thyrotoxicosis as hypothyroidism is an effectof lithium therapy. Amiodarone has the effect of causingthyrotoxicosis as a proximate effect of its heavy content ofiodine, which becomes free iodine in metabolism. This effectis likely and more marked in a patient with iodine deficiency(and of course in geographic areas where that exists).5. The answer is D. TSH, sensitive assay, is the most sensitivescreening test for overactive and underactive thyroiddisease. Although not a direct measurement of metabolism,as total and free T 4 (tetraiodothyronine) and T 3(triiodothyronine), the TSH responds in suppression beforeT 3 and T 4 begin to rise in hyperthyroidism and by elevationbefore T 3 and T 4 begin to fall. Obviously, in both the foregoinginstances, the patient would be asymptomatic.6. The answer is C. Secondary hypothyroidism. Abnormallylow or suppressed TSH occurs most often in Gravesdisease or other forms of primary hyperthyroidism, as aresult of suppression by the feedback on excessive circulatingthyroid hormones. However, this patient manifestssymptoms and signs of hypothyroidism rather than thyrotoxicosis.Abnormally low TSH occurs, of course, inhypopituitarism as well, causing secondary hypothyroidism.In this case, rather than panhypopituitarism, thepatient most likely has secondary hypothyroidism that isdue to suppressed TSH as a side effect of bromocriptine.Hashimoto thyroiditis presents in several phases but generallyresults in primary hypothyroidism in the long term,with TSH elevation.7. The answer is B. Free T 4 and TSH are generally thoughtof as constituting the best combination of initial tests ofthyroid physiology. TSH is the most sensitive screen forboth hyperthyroidism and hypothyroidism. Free T 4 is themetabolically active form of tetraiodothyronine, which inturn accounts ultimately for the overwhelming proportionof hormone output by the gland, with triiodothyronineaccounting for the remainder. I 123 thyroid uptake isunnecessarily involved for an initial investigation of theactivity status of the thyroid gland, if the TSH is suppressedand the FT 4 is elevated. Protein-bound iodine isan outmoded test for thyroid hormone activity, beingdirectly related to the T 4 content. It is no longer in usebecause not only is it not a direct measurement of hormonebut it also is subject to too many inaccuracies. Similarly,the Achilles tendon reflex exhibits time of recoveryinversely related to the state of metabolism regulated bythe thyroid. It too has inadequate sensitivity and specificity.T 3 resin uptake is an indirect measurement that hasalso fallen out of use, in favor of the free T 4 and TSH.8. The answer is D. I 123 thyroid uptake is indicated in asolitary palpable thyroid nodule with hyperthyroid functionalstatus. The radioactive radioiodine (RAI) uptakecan distinguish a hot nodule from an incidental or coldnodule in a hyperthyroid gland.9. The answer is E. FNA biopsy is indicated for most solitarynodules, the exception being a hot nodule, as judgedby the I 123 thyroid uptake and scan. This is the only way torule out carcinoma, short of open exploration.