Download Hyperthyroidism

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Hyperthyroidism
What is Hyperthyroidism? It is a condition where the thyroid gland is overactive and it produces
an excessive amount of thyroid hormones which then circulate through the blood. This hormone
Regulates heart rate, body temperature and the conversion of food into energy. (“Hyper” means
“over” in Greek). Hyperthyroidism can create Thyrotoxicosis which is an excessive intake of the
thyroid hormone.
The thyroid hormone which is produced by the thyroid gland stimulates the metabolism
of cells. The gland is located in the lower part of the neck below the Adam’s apple and it wraps
around the windpipe in a shape much like a butterfly; the wings (or lobes) are connected together
by a middle part called the isthmus. The Thyroid gland removes iodine from the blood (which
mostly comes from a diet of seafood, bread and salt) it uses it to produce the hormone. The 2
hormones are thyroxine (T4) and triiodothyronine (T3). Once released into the blood the body
converts T4 to mostly T3-which is the more active hormone that affects the metabolism of cells.
The symptoms of hyperthyroidism can include fever, sweating or feeling hot, rapid heart
rate, nausea/vomiting, irregular heartbeat, weakness, and weight loss.
The thyroid is regulated by another gland in the brain, called the pituitary. The pituitary
in turn is somewhat regulated by the thyroid hormone that is circulating in the blood and another
gland called the hypothalamus part of the brain. The hypothalamus releases a hormone of
thyrotropin (TRH) which sends a signal to the pituitary to release the thyroid stimulating
hormone (TSH). TSH then sends a signal to the thyroid to release hormones. If over activity of
any of these 3 glands happen, an excessive amount of thyroid hormones can be produced
resulting in the hyperthyroidism condition.
How is the condition diagnosed? Advanced symptoms are easy to detect but early
symptoms may be harder. In all cases a blood test is needed to confirm diagnosis. The blood test
is looking for elevated levels of the thyroid hormone. If your TSH level is high but your T4 level
is normal, you have subclinical hypothyroidism. There is one exception however, if an excessive
level of TSH is the result it is known as “secondary hyperthyroidism” and is very rare. If there
are signs in the eyes of patients where their thyroid hormone is high then a test for Graves’
disease is performed. Physicians will do an ultrasound to detect a swollen thyroid gland and look
for goiters which are nodules that can be cancerous. They will also do an antibody screening
using radioactive-labeled iodine (which will concentrate in the thyroid gland).
The recent studies are based more on what other health issues thyroid problems can lead
towards. While there is much research in the psychology field that link thyroid to bi-polar,
anxiety, depression and other severe mental disorders. Medically they are linking
Hyperthyroidism to hypertension and atrial fibrillation (AF). In one thirteen year observational
study in Denmark. The onset of AF is so prevalent that physicians are starting to test all patients
that have no history of thyroid issues that are admitted for AF for hyperthyroidism. The general
population in this research tracked all patients admitted for AF over age 18 from January 1, 1997
to December 31, 2009. There was 145,623 patients in the 13 year period that presented new onset AF. There were slightly more males (55.3%) with a mean age of 66.4 collectively.
The total of patients that developed hyperthyroidism (defined as being prescribed antithyroid drugs) in the period before the study was 4,620, of whom 62.2% were women. Results of
the study of the general population tested were 48,609 (35%) patients developed
hyperthyroidism with 39,842 (82%) of those women.
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The authors recognize the limitations to this study acknowledging that an observation
study does not factor in many clinical parameters correlated to such things as body mass index,
smoking status, lipid levels, or electrocardiogram findings. Neither did they have the findings of
types of hyperthyroidism, Graves’ disease or nodular disease. Hyperthyroidism was only defined
as use of an anti-thyroid drug which may underestimate the true incidence of hyperthyroidism.
Conclusion to this study is that patients with new on-set AF have a two-fold increased
chance to have hyperthyroidism. Increased focus on the development of hyperthyroidism during
long-term follow up with patients who have new on-set AF is warranted.
A study in Taiwan realized that heart conditions were prevalent in patients with
hyperthyroidism but they wanted to investigate if there was an increased risk for pulmonary
embolism (PE) associated as well. Data sourced for a 5 year period from the Taiwan
Longitudinal health insurance database. 8903 with hyperthyroidism compared to 44,515 patients
without any prior diagnosis were observed. Of the total 53,418 patients. 41 (0.08%) were
diagnosed with PE in the follow up period. 14 (0.16%) from the hyperthyroid group and 27
(0.06%) from the non-affected group. After adjustments for geographic regions, income,
hypertension, diabetes, pregnancy, or people taking blood thinners (anticoagulants), the study
concludes the risk for having PE during the 5 year follow up was 2.31% greater for patients that
had hyperthyroidism. A systematic analysis also supports increased risk for venous thrombotic
complications, including cerebral venous thrombosis (CVT), deep vein thrombosis (DVT)
however the authors wanted to include that another report among 633,000 patients from the US
discharged from non-federal hospitals from 1979-2005 with hyperthyroidism, was founded to not
have any more risk for PE or DVT than those not affected with hyperthyroidism. While they
realize an observation is less accurate than those from actual hospital records, they give evidence
and argument of their hypothesis to be true with statements as “there may be a surveillance bias,
in that patients with hyperthyroidism are more likely to receive frequent check-ups than
comparison patients, thus increasing the probability of their PE being detected by a physician.
However, almost all PE cases need immediate emergency care. Therefore, the possibility of
surveillance bias does not compromise our findings”. The study concludes that all physicians of
patients with hyperthyroidism should be alerted of the finding for PE and DVT and make
appropriate measures in major surgery to taking action to prevent the findings by specific means
for treatment.
Another study in Taiwan investigated the association between hyperthyroidism and
cancer (especially thyroid cancer) risk. A random sample of individuals from the Taiwan
National health insurance database were observed. They found 17,033 patients to have newly
diagnosed hyperthyroidism between 2000 and 2005. They also found another 34,066 patients
without hyperthyroidism. During the follow-up study, cancer was diagnosed in 1.23% of patients
with hyperthyroidism and only 1.02% of the non-hyperthyroidism group were diagnosed. The
conclusion obviously was the hyperthyroidism group was at more risk and the longer the
duration of hyperthyroidism, the greater the risk.
There are studies on pregnant women affected to analyze the effect on the child.
Scientists are doing many tests in lab rats from diet to different types of drugs to treat patients.
There were multiple studies on different kinds of heart conditions that are constantly encountered
either in people with hyperthyroidism or after being diagnosed with the actual heart issues the
patient was diagnosed with hyperthyroidism as the study above. Above all patients need to be
seen on a regular basis by a physician most likely an endocrinologist that specializes in thyroid
issues and also be very educated in the risks associated with having hyperthyroidism.
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Works Cited
President and Fellows of Harvard College, Could you have a thyroid problem and not know it?
Harvard Women's Health Watch. Jan 2013, Vol. 20 Issue 5, p6-7. 2p. 1 Illustration.
Selmer, Christian; Hansen, Morten Lock; Olesen, Jonas Bjerring; Mérie, Charlotte; Lindhardsen,
Jesper; Olsen, Anne-Marie Schjerning; Madsen, Jesper Clausager; Schmidt, Ulla; Faber, Jens;
Hansen, Peter Riis; Pedersen, Ole Dyg; Torp-Pedersen, Christian; Gislason, Gunnar Hilmar.
New-Onset Atrial Fibrillation Is a Predictor of Subsequent Hyperthyroidism. PloS ONE.
Feb2013, Vol. 8 Issue 2, p1-9p.Illustration.
Yeh, N, Chou, C, Weng, S, Yang, C, Yen, F, Lee, S, Wang, J, Tien, K
Hyperthyroidism and Thyroid Cancer Risk, Experimental & Clinical Endocrinology & Diabetes.
Jul2013, Vol. 121 Issue 7, p402-406. 5p.Illustration.
By: LIN, H.-C.; YANG, L.-Y.; KANG, J.-H, Increased risk of Pulmonary Embolism among
patients with Hyperthyroidism, Journal of Thrombosis & Haemostasis.
Oct2010, Vol. 8 Issue 10, p2176-2181. 6p