« Ord's Thyroiditis | Main | Hashimoto's »


Another common grouping of symptoms of thyroid problems, Hyperthyroidism (thyrotoxicosis or "fast thyroid gland") is the clinical syndrome caused by an excess of circulating free thyroxine (T4) and free triiodothyronine (T3), or both. Major causes in humans are Graves' disease (the most common etiology with 70-80%), toxic thyroid adenoma, toxic multinodular goitre, and subacute thyroiditis.

signs and symptoms of hyperthyroid

Major clinical features in humans are weight loss (often accompanied by a ravenous appetite), fatigue, weakness, hyperactivity, irritability, apathy, depression, polyuria and sweating. Additionally, patients may present with a variety of symptoms such as palpitations and arrhythmias (notably atrial fibrillation), dyspnea, infertility, loss of libido, nausea, vomiting, and diarrhea. In the elderly , these classical symptoms may not be present and they may present only with fatigue and weight loss leading to apathetic hyperthyroidism.

Neurological manifestations are tremor, chorea, myopathy, and periodic paralysis. Stroke of cardioembolic origin due to coexisting atrial fibrillation may be mentioned as one of the most serious complications of hyperthyroidism.

As to other autoimmune disorders related with thyrotoxicosis, an association between thyroid disease and myasthenia gravis has well been recognised. The thyroid disease, in this condition, is often an autoimmune one and approximately 5% of patients with myasthenia gravis also have hyperthyroidism. Myasthenia gravis rarely improves after thyroid treatment and relation between two entities is yet unknown. Some very rare neurological manifestations that are reported to be dubiously associated with thyrotoxicosis are pseudotumor cerebri, amyotrophic lateral sclerosis and a Guillain-Barr├ę like syndrome.

diagnosis of hyperthyroid

A diagnosis is made through a blood test, by measuring the level of T4 in the blood. High T4 levels are considered indicative of hyperthyroidism. If the index of suspicion is low, many doctors prefer to measure thyroid-stimulating hormone (TSH). If TSH is suppressed, there may be uncontrolled production of T4, while a normal TSH generally rules out thyroid disease. Measuring specific antibodies, such as anti-TSH-receptor antibodies in Graves' disease, may contribute to the diagnosis. Additionally, scintigraphy may be required.

treatment of hyperthyroid

The major and generally accepted modalities for treatment of hyperthyroidism in humans are:

  • surgery
  • radioiodine treatment
  • thyrostatics - drugs that inhibit the production of thyroid hormones, such as methimazole (Tapazole┬«)

If too high a dose is used in pharmacological treatment, patients can develop symptoms of hypothyroidism. Hypothyroidism is also a very common result of surgery or radiation treatment as it is difficult to gauge how much of the thyroid gland should be removed. Supplementation with levothyroxine may be required in these cases.

Posted by Staff at May 19, 2005 9:20 AM

blog comments powered by Disqus

Comments Archive

I was diagnosed with hypothyroidism eight years ago. I take Armour Thyroid, and like my TSH to remain on the low side (.9 usually). I just had my TSH tested and the level was quite low, 0.15. I am going to have surgery this Friday. I am going to donate my kidney, which is obviously an elective procedure. I am concerned with the atrial defibrillation. I haven't felt anything, is there any way that I could be experience this without symptoms? They are going to do an EKG the day before the surgery... any comments?

Posted by: Sara Anderson at October 11, 2005 5:25 AM

Can you run a low grade fever with hypothyroid condition???

Posted by: M Sowa at July 20, 2006 2:59 PM

I was diagnosed 1/06 with hyperthyroid and taking 5mg of Tapazole. I have lost 90 lbs and feel great except for cramping in my legs. Could this be due to Tapazole? Thanks for your input.

Posted by: Shirley at August 7, 2006 9:52 AM

I had/have thyroid cancer. On Aug.16,1995 I had a thyridectomy and removal of some lymph nodes as well. The following month I had more lymph nodes removed that had thy. cancer. And follower with radioactive iodine treatments. And then 6 years later I had more thy . cancer removed from my neck and behind my breast plate. it is now 2006 and I am now 31 years old. I still have problems with regulating my thy. levels. I take levothroid and cytomel daily. I have also had kidney failure and am going on 8 years for a kidney transplant...I often wonder if one lead to the other?!? Good luck to all of you out there with thy. problems... I feel your PAIN!!

Posted by: Charity at September 19, 2006 2:19 PM

I was just diagnosed with hyperthyroid. Will this cause me to gain weigh? I am taking 50mcg of Levothyroxine. There was a posting by an individual that was prescribed Tapazole and had lost 90 pounds!
Thanks for any input out there!

Posted by: Linda Maples at September 23, 2006 3:18 PM