Remember the Thyroid to Avoid Public Humiliation

George H. W. Bush and His Thyroid

(Thank you for the positive feedback about my post on Peter Schwartz and how the death of a contestant during a TV quiz show affected his career.  https://pauldthompsonmd.substack.com/p/can-a-tv-quiz-show-kill-you. I received a note from Professor Schwartz himself.  It’s nice to know that the blog reaches Italy.  Those of you interested in electrophysiology might also enjoy the post on the relationship between cross-dressing and the Brugada Syndrome.  https://pauldthompsonmd.substack.com/p/what-does-cross-dressing-have-to.)

I published today’s post on my Medium blog on January 15, 2020, but have altered it here so that you can avoid clinical humiliation.

George H.W. Bush was President. I had a full head of hair, so I occasionally did television commentary at distance running events for ABC and was also an infrequent medical “expert” for Good Morning America (GMA). It was May 1991 when President Bush developed atrial fibrillation (AF) while jogging at Camp David. GMA wanted me in NYC the next morning to discuss AF. I was at Brown University in Providence, RI and had an NIH grant examining how distance runners metabolized HDL cholesterol. I had just spent a week separating the  runners’ HDL from their plasma and labeling the HDL with radioactive iodine¹²⁵. I was scheduled to inject the runners the next morning so we could determine how rapidly the runners catabolized the HDL protein. (We showed that runners catabolize HDL proteins more slowly.) (1) I explained to ABC that I could not go to NYC because of this study so ABC decided to send a TV truck to Providence. They wanted me on air at 7:05 AM. I called our 10 research subjects and arranged for them to come to the research lab starting at 4:30 AM so that my last injection would start at 6:45 AM, one subject every 15 minutes. Getting all the subjects injected by 7 was no small feat because I had to get the intravenous line started and make sure it was flowing well so that I did not inject the radioactive HDL any place but in the vein. I also needed to draw another blood sample 10 minutes after the injection because we were using the distribution of the iodine¹²⁵ to determine plasma volume.  Plasma volume was required for calculating of HDL catabolism, and is important in the runners because exercise expands plasma volume.  (The runners had 500 ml more plasma volume than the controls despite the runners’ body weights.)(1)  Unfortunately, the last subject was late so I ran around like crazy getting him going and the infusion done. I ran downstairs to the TV truck, combed my hair (those were the days) and at 7:05 AM started answering questions about atrial fibrillation. I did well until the host, Charlie Gibson, asked about the causes of atrial fibrillation. I discussed enlargement of the atrium, alcohol, and other possible causes but never mentioned hyperthyroidism. So what did George W. H. Bush have? Hyperthyroidism, of course. Interestingly, his wife, Barbara, also had hyperthyroidism.(2) Within minutes my office phone was ringing with all my “friends” from around the country reminding me that I had forgotten hyperthyroidism. So, when I lecture about atrial fibrillation in athletes, an area of interest since 2009, (3,4) I always start the lecture with a slide of George H. W. Bush. So, here are the rules cardiologists need to know about the thyroid to avoid humiliating themselves in clinic or on national TV.

-       The average dose of thyroid in the US is 112 mcgs. I like the fellows to know this so that they know that patients taking less are more likely to be hypothyroid and that patients taking more may be hyperthyroid.

-       Everyone with AF needs a TSH. It used to be that clinicians would dismiss hyperthyroidism if the patient did not appear hyperthyroid, but “apathetic hyperthyroidism” is so common, especially in the elderly, that a TSH is always mandatory.

-       Everyone with any lipid disorder also needs a TSH. I have posted about this before. (5) Hypothyroidism reduces LDL receptor activity by reducing expression of the LDL receptor gene.  Hypothyroidism also can increase TG levels and reduce HDL, so “every patient with a lipid disorder is hypothyroid until proven otherwise.”

-       Amiodarone is loaded with iodine — 37% by weight (6) and iodine can cause both hypo- and hyperthyroidism. Excess iodine inhibits thyroid synthesis, the Wolff-Chaikoff effect, (7) which is why iodine is part of the treatment for thyroid storm. Iodine can also cause thyrotoxicosis, the “Jod-Basedow” phenomenon, also known as iodine-induced hyperthyroidism. This happens in patients who have subclinical hyperthyroidism, but who do not have enough iodine to become toxic. (8) Consequently, amiodarone can also cause both hypo and hyperthyroidism. The contrast used in angiography also contains iodine so contrast can cause the Jod-Basedow phenomenon.  In fact, contrast is now the most common cause of this condition. (8) Remember this if a patient becomes hyperthyroid not long after angiography.

-       Hypothyroidism also increases lipoprotein (a), which is an important risk factor in CAD.(9)  That may be another reason, besides the LDL, that hypothyroid patients get accelerated atherosclerosis.  If you are unfamiliar with lipoprotein (a), check out my post on “Avoiding False Reassurance”. (10)

So, remember George H.W. to avoid missing thyroid disease in cardiac patients.

1. Thompson PD, Cullinane EM, Sady SP, Flynn MM, Chenevert CB, Herbert PN. High density lipoprotein metabolism in endurance athletes and sedentary men. Circulation 1991;84:140–52.

2. https://www.politico.com/magazine/story/2019/04/01/barbara-bush-book-george-h-w-bush-bill-clinton-1992-election-graves-disease-226337/ (accessed 11/1/2024)

3. Sorokin AV, Araujo CG, Zweibel S, Thompson PD.4. Atrial fibrillation in endurance-trained athletes. Br J Sports Med. 2011 Mar;45(3):185-8. Epub 2009 Jul 13. PMID: 19654095 

4. Thompson PD. Physical Fitness, Physical Activity, Exercise Training, and Atrial Fibrillation: First the Good News, Then the Bad.

J Am Coll Cardiol. 2015 Sep 1;66(9):997-9. PMID: 26314525 

5. https://pauldthompsonmd.substack.com/p/every-patient-with-any-lipid-disorder

6. https://emedicine.medscape.com/article/129033-overview

7. Burch HB. Drug Effects on the Thyroid. N Engl J Med 2019;381:749–61.

8. Pokhrel A, Tun MM, Miah SS, Raina JS, Zahedi, T.  Thyrotoxicosis Surprise: Jod-Basedow Phenomenon Following IV Contrast Administration. Cureus. 2022 May 4;14(5):e24742.  PMID: 35686254

9. Tsimikas S. A test in context: lipoprotein (a): diagnosis, prognosis, controversies, and emerging therapies. J Am Coll Cardiol 2017;69:692–711.

10. https://pauldthompsonmd.substack.com/p/dont-give-false-reassurance (accessed November 1, 2024.

#hyperthyroidism #atrialfibrillation #GeorgeHWBush #Goodmorningamerica #hypothyroidism #amiodarone #iodine