THE JOURNAL OF FAMILY PRACTICE

Taryn Taylor, MD, CCFP What caused this case of Charles Czarnowski, MD, CCFP asymptomatic ? Bruyere Family Medicine Center, University of Ottawa Everything pointed to an exogenous cause, but our patient [email protected] denied taking anything. Only later did she mention a diet aid.

Practice recommendations stimulating hormone (TSH) test to rule • When taking a medication history, always out . ask specifi cally about the use of all The test showed a TSH of 0.2 mIU/L nonprescription products—including all (normal range is 0.35-5.0 mIU/L). Her over-the-counter remedies, vitamins, physician ordered retesting a week later “natural” herbal supplements, and dietary and this time, Mary’s TSH was nor- aids (C). mal (1.99 mIU/L). The laboratory report also showed elevated free triiodothyro-

• Counsel patients about the need for nine (T3) of 8.1 pmol/L (normal range

caution when taking dietary supplements 2.6-5.7 pmol/L) and free thyroxine (T4) and herbal remedies, which lack regulation >70 pmol/L (normal, 10-20 pmol/L); and standardization and may contain negative antithyroid peroxidase and FAST TRACK ingredients not listed on the label (A). antithyroglobulin antibodies; normal Our patient complete blood count, calcium, and Strength of recommendation (SOR) alkaline phosphatase; and low levels hadn’t mentioned A Good-quality patient-oriented evidence of . The patient had no the European B Inconsistent or limited-quality patient-oriented evidence C Consensus, usual practice, opinion, disease-oriented symptoms and no personal or family dietary evidence, case series history of . She also de- supplement nied taking thyroid medications. hen Mary J,* an overweight she was taking 47-year-old Caucasian wom- to increase W an, came in for an annual ❚ In search her metabolism physical examination, she appeared to of an explanation be in good health. She denied any re- On examination, her physician found because she cent illness, and reported that an oral no signifi cant thyroid enlargement or assumed it contraceptive was the only medication tenderness. However, the patient’s thy- was safe. she was taking. The patient’s only com- roid was somewhat boggy on palpation. plaint: She was having diffi culty losing There was no exopthalmos or pretibial weight despite complying with a low- . Mary’s blood pressure was calorie diet and exercise regimen for the 144/98 mm Hg (with no prior history last 6 months. Her comments prompted of hypertension), her heart rate was 84, her physician (CC) to order a thyroid- and she was afebrile. Her physician

* The patient’s name has been changed to protect her privacy.

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found no obvious tremors, hyperdy- risks associated with their use, and be- namic apex, or hyperrefl exia on physi- ing alert to potentially dangerous side cal exam. effects. To rule out laboratory error from the second set of tests, her physician or- dered yet another round of blood work. ❚ Thyrotoxicosis factitia: A diagnosis of hyperthyroidism was con- An exogenous cause

fi rmed by elevated 4T (>70 pmol/L) and T3 Thyroid hyperactivity can occur when (6.2 pmol/L). As in the previous test, the excessive quantities of thyroid hor- patient’s TSH was in the normal range mone are ingested. The excessive intake (1.54 mIU/L). may be associated with treatment for hypothyroidism, or, as in Mary’s case, may be linked to overuse (or abuse) of ❚ Detailed questioning a diet aid in an attempt to lose weight.2 solves the mystery Often, the condition can be traced to At follow-up, the patient was again an iodine-containing substance such asked about exogenous thyroid intake, as kelp—a widely used dietary aid that which she had initially denied. After we’ll discuss in greater detail in a bit. further questioning about what she Iodide is an inorganic salt that is was ingesting, Mary acknowledged that absorbed through the gastrointestinal she had been taking Pu Erh—a Euro- mucosa and transported to the thyroid pean dietary supplement marketed as a gland, where it is trapped and concen- means of increasing metabolism to help trated for thyroid hormone synthesis.3 with weight loss—3 times daily for more Consuming large quantities of foods or than 3 months. She hadn’t mentioned other products that contain iodine—such it before because it hadn’t occurred to as iodized salt, shellfi sh, cough syrups, her to question its safety. multivitamins, or medications such as Her physician advised her to dis- amiodarone and interferon alpha, as well FAST TRACK continue the supplement immediately, as kelp—can cause hyperthyroidism. Chromium and to have her blood work retested in a month. Within 5 weeks, all her lab What’s in that weight-loss aid? is a popular values returned to normal. (For more Pu Erh, the dietary supplement Mary weight-loss on lab values, see “Investigating thyroid was taking, was not available for analy- supplement dysfunction: What to test for” on page sis; it was purchased in Poland and the whose effi cacy 205. ) patient had exhausted her supply by the time her physician told her to stop tak- and long-term Natural does not = safe ing it. Each capsule contains 400 mg of safety are With an ever-increasing overweight pop- red tea extract with 15 mcg chromium, uncertain. ulation, there is growing concern about according to the label. the misuse of diet aids. It is important Red tea and chromium. There are no for patients to be cautious when using reports associating red tea with thyroid dietary supplements because of the lack dysfunction, but chromium is a popular of regulation and standardization. Yet weight-loss supplement whose effi cacy such products are often marketed as and long-term safety are uncertain.4 It “natural,” which may be interpreted as is unlikely that Mary’s hyperthyroid- an assurance of safety.1 Family physi- ism was associated with chromium in- cians can play a crucial role in primary take, however, as multivitamins often prevention by inquiring about the use contain 100 mcg of chromium—nearly of over-the-counter substances includ- 7 times the quantity in each Pu Erh ing “natural” herbal supplements and capsule—with no reported thyroid side dietary aids, advising patients of the effects.

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204_JFP0409 204 3/18/09 11:37:43 AM Asymptomatic hyperthyroidism ▼

Did the supplement contain a thyroid TABLE extract? It’s possible, of course, that the Investigating thyroid supplement contained a thyroid extract, dysfunction: What to test for which would explain the resolution of symptoms after Mary stopped taking it. The single most useful screening test for But without analysis of the product, we thyroid dysfunction is serum TSH. Normal can’t be sure. Our suspicion, of course, is TSH levels effectively rule out hyperthyroidism and hypothyroidism, and obtaining serum that it did. T and T levels is usually not indicated.8 Another possible, but unlikely, ex- 3 4 Circulating levels of free T3 or T4 are increased planation. Theoretically, the fl uctuating in hyperthyroidism and thyrotoxicosis, while TSH could have been related to silent TSH levels are low to immeasurable (<0.01 9 or subacute thyroiditis, in which T4 can mU/L). remain elevated for 1 to 3 months. The The term “thyrotoxicosis” is used to denote fact that Mary had no history of cold the excess of thyroid hormone levels without or fl u symptoms in the month preced- thyroid hyperfunction or increased biosynthe- ing the initial TSH was inconsistent sis—ie, excess intake, excess release without with this alternative diagnosis, howev- synthesis, or syndromes of pituitary resistance er. Painless is also unlikely, to .10 Low thyroglobulin in as it is autoimmune in origin and the association with hyperthyroidism is a hallmark patient’s antithyroid antibodies were of exogenous thyroid intake, also known as 11 negative. The low thyroglobulin level thyrotoxicosis factitia. supported an exogenous cause of hy- perthyroidism. instance of probable transient hyperthy- roidism in a patient taking kelp in 2 dif- ferent diet supplements.6 ❚ Other supplements Tiratricol (Triac), a substance that has and thyroid dysfunction weak thyromimetic effects, resulted in a Mary’s presentation is a single case case of documented hyperthyroidism sec- indicating a possible link between a ondary to its use.1 FAST TRACK weight-loss supplement and asymp- Other reports. In Japan, the weight- Low thyroglobulin tomatic hyperthyroidism—a clinically reducing herbal medicines, Dream important condition that may be asso- Shape and Ever Youth, became available in association with ciated with disorders such as paroxys- in 2000. Twelve patients subsequently hyperthyroidism mal atrial fi brillation and osteoporosis. developed thyrotoxicosis after taking is a hallmark of This is only one of a number of case these herbal medicines, both of which exogenous thyroid reports of patients taking dietary sup- were found to contain plements who have developed thyroid and thyroxine.7 intake. dysfunction. As early as 1986, researchers have Kelp. Long used as a dietary supple- described several patients who devel- ment, especially in Asia, kelp has been oped thyrotoxicosis from Enzo-Caps, a linked to thyroid dysfunction. One case nonprescription diet aid manufactured report describes a 72-year-old woman in Peru. The product was touted as “a with a history of thyroid disease hav- natural food product of papaya, garlic, ing typical symptoms of hyperthyroid- and kelp” to assist with weight reduc- ism while ingesting 4 to 6 kelp tablets tion. Researchers obtained the supple- daily for 1 year. Her TSH concentration ment for biochemical analysis and

was low, while total T3 and T4 levels found that it had been adulterated with were high. After discontinuing the kelp thyroid hormones, which led to thyro- tablets, the hyperthyroidism resolved, toxicosis factitia.2 and thyroid function tests returned to Patients in the report complained normal.5 Another report describes an of palpitations, weakness, fatigue,

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IN THE UNITED STATES, headache, diaphoresis, irritability, and THE PRESS CANNOT BE CENSORED. nervousness, and had elevated serum T3 and T4 levels. Thyroglobulin levels were not determined, but would have been useful in differentiating thyrotox- THE INTERNET CANNOT BE CENSORED. icosis factitia from (Graves’ disease, thyroiditis, nodular POLITICAL ADVERTISING goiter).2 These reports, as well as our own CANNOT BE CENSORED. experience, leave little doubt as to the importance of asking pointed questions about all prescription and nonprescrip- WHY ARE SOME MEMBERS OF tion products a patient is taking. As CONGRESS & ACADEMIA TRYING TO we can attest, a little persistence goes a CENSOR MEDICAL COMMUNICATIONS? long way when it comes to identifying that agent your patient didn’t think was worth mentioning. ■

Correspondence Diabetes. Cancer. Obesity. Respiratory disease. Taryn Taylor, MD, CCFP, Bruyere Family Medicine Center, America’s medical professionals are busier University of Ottawa, 206 Monterey Drive, Ottawa, Ontario, Canada K2H 7A8; [email protected] than ever. How can they stay current with medical advances and still improve their Disclosure The authors reported no potential confl ict of interest rel- patients’ well-being? evant to this article.

Information is part of quality care. Yet References government controls threaten to keep doctors 1. Bauer BA, Elkin PL, Erickson D, et al. Symptomatic hyperthyroidism in a patient taking the dietary sup- in the dark about current medical advances. plement tiratricol. Mayo Clin Proc. 2002;77:587- 590. Restrictions on how much information 2. Braunstein GD, Koblin R, Sugawara M, et al. Un- intentional thyrotoxicosis factitia due to a diet pill. consumers and doctors can know about current Western J Med. 1986;145:388-391. and new treatments reduce their ability to 3. Clark CD, Cliford D, Bertram B, et al. Effects of advocate for care. kelp supplementation on thyroid function in euthy- roid subjects. Endocr Pract. 2003;9:363-369. Using censorship as a policy tool to control 4. Saper RB. Common dietary supplements for weight loss. Am Fam Physician. 2004;70:1731- healthcare costs is a bad idea! Yet that’s what 1738. vocal pockets of academic medicine and 5. Shilo S, Hirsch HJ. Iodine-induced hyperthyroidism in a patient with a normal thyroid gland. Postgrad Congress have in mind. Med J. 1986;62:661–662. 6. Eliason, BC. Transient hyperthyroidism in a patient We are concerned that some members of taking dietary supplements containing kelp. J Am Congress and academia are seeking to restrict Board Fam Pract. 1998;11:478-480. the content of CME and other industry-sponsored 7. Ohye H, Fukata S, Kanoh M, et al. Thyrotoxicosis caused by weight-reducing herbal medicines. Arch communications without input from Intern Med. 2005;165:831-834. practicing physicians. 8. Demers LM. Thyroid disease: pathophysiology and diagnosis. Clin Lab Med. 2004;24:19-28. 9. Goichot B, Perrin AE. Thyrotropin as fi rst-line thy- Information is the fi rst step to care. roid test. Lancet. 2001;358:509. To learn more, visit cohealthcom.org. 10. Monaco F. Classifi cation of thyroid diseases: sug- gestions for a revision. J Clin Endocrinol Metab. 2003;88:1428-1432.

Th is message brought to you as a public service by the 11. Parmar MS, Sturge C. Recurrent hamburger thyro- toxicosis. CMAJ. 2003;169:415-417. Coalition for Healthcare Communication.

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