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Transfer of this blog

posted Aug 29, 2010, 2:03 PM by Medhavi Jogi

We have created a new location for our updates. Thyroid-only updates are will now be posted on our facebook fan page and all our general-endocrine updates will be located on our endocrine blog

Is your soap hurting your thyroid function?

posted Aug 1, 2010, 5:14 AM by Medhavi Jogi   [ updated Aug 1, 2010, 9:56 PM ]

In the last few months there have been increasing news reports that antimicrobial soaps act as endocrine disruptors and have a harmful impact on endocrine function. Endocrine disruptors are natural and man-made chemicals that can either mimic or disrupt the action of hormones. Their impact on human biology is still unclear, but they have been implicated in a number of reproductive and health problems in animals. The active ingredient that is under question is triclosan. Apparently the FDA has been doing studies on this issue for some time, but what prompted all this? 

Well, looking back into the published medical literature on this, there is an interesting chronology that has lead up to this debate. Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) is a chlorinated phenolic antibacterial compound that is widely used in soaps, toothpastes, cosmetics, fabrics and plastics (1) , typically at a concentration of 0.1–0.3% (2) . The structure of triclosan is similar to bisphenol A and dioxins (3) , and it is degraded into various chlorinated dibenzo-p-dioxins by heat and ultraviolet irradiation (4) . The reason this compound is used in soap is for its broad spectrum antibacterial and antifungal action which is accomplished by blocking lipid synthesis by specifically inhibiting the enoyl-acyl carrier protein reductase (ENR or FabI) (5) in both prokaryotic and eukaryotic cells (6). Since the substance is so abundantly used, it is measurable in the water we drink and therefore some can be detected in human blood. In fact, it was detectable in 75% of urine samples in the US National Health and Nutritional Examination Survey in 2003–2004, with higher levels in individuals with the highest household income.(7) Because triclosan is present in such a variety of personal care and household products, in the ecosystem, and in human body fluids, there is a potential concern for adverse effects on human health. 

The story gets interesting between 2002 to 2006 when it was shown to bioaccumulate and have endocrine effects in fish and amphibians (8) Studies in frogs and rats showed reduced production of the thyroid hormones T3 and T4. TSH values were not shown to have been effected. (9) Although interspecies differences exist, effects on the thyroid of this magnitude, particularly T4, should be carefully evaluated because the thyroid hormone status in a pregnant women seems to have sustained neuropsychological effects on the child after birth.  The effects on human thyroid endocrine function on not entirely clear. Awareness of endocrine disruptors has increased in the last few decades regarding common environmental exposures may affect thyroid function in humans and other species. Individuals may be most vulnerable to these effects in utero and in infancy, when thyroid hormone is needed for normal neurodevelopment. The list of endocrine disruptors of the thyroid is long and can be categorized based on the negative effects they have on different aspects of thyrod hormone function. : (11)  Use the thyroid glossary if some of the terms are unfamiliar.

Reduce thyroid perioxidase activity:  
    •   Isoflavones
Compounds that decrease T4 half life by decreasing T4 clearance:      
    • pesticides, dioxin, furans
Reduce the ability of the thyroid to uptake iodine:      
    • perchlorate, thiocyanate, nitrate
Inhibit transport of thyroid hormone in the blood: 
    • polybrominated diphenylethers  (PBDE's), Hydroxylated Polychlorinated biphenyls (PCB's)
Inhibition of peripheral T4 to T3 conversion
    • sunscreens, styrenes
Have direct effects on peripheral tissue thyroid hormone receptors: 
    • PCBE's, PCB's, isopropylidenediphenol or bisphenol-A  (BPA), Triclosan


References
  1.  McMurry et al., 1998
  2.  Sabaliunas et al., 2003
  3. Cabana et al., 2007
  4. Kanetoshi et al., 1987
  5. Heathet al., 1999; Newton et al., 2005
  6. Guillen et al., 2004; Lygre et al., 2003; Villalain et al., 2001
  7. Dayan, 2007, Calafat et al., 2008
  8. Adolfsson-Erici et al., 2002; Foran et al., 2000; Ishibashi et al., 2004; Veldhoen et al., 2006
  9. Veldhoen et al., 2006; Crofton et al., 200; Zorrilla et al. 2009
  10. Haddow et al., 1999; Morreale de Escobar et al., 2000
  11. Pearce and Braverman et al. 2009


If you would like to learn more from the endocrinologists at Houston Thyroid and Endocrine Specialists, either click request online registration to become a new patient or contact our office at 713.795.0770 to schedule an appointment 8:30am - 5:00pm, central standard time. 


Dr. Jogi and Dr. Elhaj welcome patients from all over Texas, as well as other states and countries. The office, located in the Texas Medical Center, serves the Houston metro area.
West University, River Oaks, Bellaire, Heights, Memorial, Jersey Village, Beaumont,  Galveston, Clearlake, Midtown, Uptown, Pearland, Katy, Sugar Land, and Kingwood, San Antonio, Austin, Louisiana, Oklahoma, Lufkin, Midland, Dallas, Missouri City, Alief, Lake Charles, La Grange, United States, USA

Website Satisfaction Survey

posted Jun 18, 2010, 5:54 AM by Medhavi Jogi

Please let us know what you think of this site and suggestions for more topics on a 30 second survey. 

Propylthiouricil

posted Jun 16, 2010, 6:15 PM by Medhavi Jogi

The United States Food and Drug Administration (FDA) has added a Boxed Warning to the label for propylthiouracil (PTU), a drug used to treat hyperthyroidism, to include information about reports of severe liver injury and acute liver failure, some of which have been fatal, in adult and pediatric patients using this medication. Approximately 15,000 adults are, therefore, estimated to begin PTU therapy per year. If the frequency of PTU-related severe liver damage is approximately 0.1% in adults, based on available data, approximately 15 adults will develop related severe hepatic injury annually in the United States. If 10% of these individuals develop liver failure resulting in liver transplantation or death (1:10,000 incidence), each year one or two individuals with Graves’ disease in the United States will die or require a liver transplant after PTU exposure

The new, official warning also states that for patients being started on treatment for hyperthyroidism it may be appropriate to reserve use of propylthiouracil for those who cannot tolerate other treatments for hyperthyroidism. These other treatments for hyperthyroidism include such as methimazole, radioactive iodine or surgery. 

Indications for PTU are:

  1. Pregnant women during their first trimester  or just prior to the first trimester (where the risk of methimazole-associated birth defects might outweigh the risks of PTU).  There are 4 million births per year in the United States, and with a 0.1% frequency of Graves’ disease in pregnancy, approximately 4000 women per year would be expected to be treated with antithyroid drugs. Most of them would be treated with PTU, per current practice guidelines. Consequently, it can be estimated that four women per year will have severe PTU-related hepatic complications, based on generally reported rates of severe liver injury in adults, although no pregnancy-specific data are available.
  2. Patients with life-threatening thyrotoxicosis or thyroid storm (because of PTU's ability to inhibit peripheral conversion of T4 to T3)
  3. Patients with adverse reactions to MMI (other than agranulocytosis) who are not candidates for radioiodine or surgery.


References:

Bahn, RS, Burch, HS, Cooper, DS, et al. The Role of Propylthiouracil in the Management of Graves' Disease in Adults: report of a meeting jointly sponsored by the American Thyroid Association and the Food and Drug Administration. Thyroid 2009; 19:673.

Cooper, DS, Rivkees, SA. Putting propylthiouracil in perspective. J Clin Endocrinol Metab 2009; 94:1881.



If you would like to learn more from the endocrinologists at Houston Thyroid and Endocrine Specialists, click here to request online registration. Or you can contact our office at 713.795.0770 to schedule an appointment 8:30am - 5:00pm central standard time. 


Dr. Jogi and Dr. Elhaj welcome patients from all over Texas, as well as other states and countries. The office, located in the Texas Medical Center, serves the Houston metro area.
West University, River Oaks, Bellaire, Heights, Memorial, Jersey Village, Beaumont,  Galveston, Clearlake, Midtown, Uptown, Pearland, Katy, Sugar Land, and Kingwood, San Antonio, Austin, Louisiana, Oklahoma, Lufkin, Midland, Dallas, Missouri City, Alief, Lake Charles, La Grange, United States, USA

Is it my thyroid?

posted May 16, 2010, 9:33 AM by Medhavi Jogi   [ updated Jun 1, 2010, 8:28 PM ]

We have added a section to the site to address the most common questions that patients ask endocrinologists. We will start the with most common question which is "is it my thyroid?"   This section would be a good starting point to find out general information about the thyroid and what kind of thyroid problem you have, if any.  





The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Please check with a physician if you suspect you are ill.

Thyroid Glossary

posted May 1, 2010, 5:33 AM by Medhavi Jogi

We have noticed that patients have many questions about the sometimes confusing terminology used to describe thyroid diseases.  We have created a list of common terms related to the thyroid in this thyroid glossary which we will continually update.  Please use the suggestion tab in your patient portal if there are other terms you would like us to define. 

Graves Disease in Pregnancy

posted Apr 27, 2010, 5:44 PM by Medhavi Jogi

The endocrinologist has a very important role in the counseling and management of women with active Graves disease during pregnancy or in women who have the disease and want to conceive.  Gestational thyrotoxicosis is the most common form of hyperthyroidism in pregnancy followed by Graves hyperthyroidism. These two conditions may be difficult to differentiate in the first trimester. Antithyroid medications (propylthiouricil and methimazole) remain the main way to treat hyperthyroidism in pregnancy. The goal of treatment with these medications is to achieve Free T4 Index (FTI) levels in the upper one third of the normal range with medication adjustments every 2-4 weeks.  The FTI remains constant during pregnancy and avoids the mis-diagnosis of 'hypothyroxinemia'.  Previous recommendations had suggested the use of the direct Free T4 (FT4) assay, but this method is flawed if non pregnant reference ranges are used since the levels of FT4 decrease below the normal range in the second and third trimesters.  

Thyroid Cancer Prognosis

posted Apr 22, 2010, 5:58 PM by Medhavi Jogi

The incidence of thyroid cancer is steadily rising in the United States over the past three decades.  Dr. Jogi and Dr. Elhaj review this trend and report on the prognosis of thyroid cancer in this news article.  The long term management of thyroid cancer should be overseen by your endocrinologist.  

Radioactive Iodine Exposure

posted Apr 22, 2010, 5:52 PM by Medhavi Jogi   [ updated Apr 22, 2010, 6:22 PM ]

Recently USA today had an article about the risks posed to the public from radioactive iodine.  Currently the American Thyroid Association, The Endocrine Society, the Society of Nuclear Medicine, and the American Association of Clinical Endocrinologists all have guidelines based on scientific evidence that the current practice of outpatient radioactive iodine therapy is safe for the general public; see JAMA 283: 2272-2274, 2000.  Currently the Nuclear Regulatory Commision (NRC) has not changed the regulations, but we are waiting to see if new regulations will be passed.  The American Thyroid Association is currently studying this issue. 

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