Last Updated on Aug 03, 2016

What is Hyperthyroidism?

Hyperthyroidism is a condition in which the thyroid gland makes excessive amount of thyroid hormone.

The thyroid gland is located in the lower part of the neck, below the Adam's apple. The thyroid gland produces the hormones thyroxine (T4)and triiodothyronine (T3), which regulate many aspects of our metabolism. It also affects the heart, muscles, bones and cholesterol.


Normal Thyroid Levels

Test From Units
TSH - Thyroid Stimulating Hormone 0.4 - 4.0 mU/L (milliunits per litre)
FT4 - Free T4 (the active part of thyroxine) 9.0 - 25.0 pmol/L (picomoles per litre)
FT3 - Free T3 (the active part of triiodothyronine) 3.5 - 7.8 pmol/L (picomoles per litre)

A low TSH level with a high FT4 level and a high FT3 level indicate hyperthyroidism (over-active thyroid).

Many diseases and conditions can cause hyperthyroidism. Graves’ disease is the most common cause of hyperthyroidism.

Having too much thyroid hormone speeds up most of the things in the body. A person with hyperthyroidism may lose weight quickly, have a rapid heartbeat, sweat a lot, or feel nervous and moody. Some patients have no symptoms at all and hyperthyroidism is diagnosed accidentally.

Hyperthyroidism can be easily treated with the help of anti-thyroid medications, radioactive iodine or surgery. Without treatment, hyperthyroidism can lead to serious complications of the heart and bone.

What are the Causes of Hyperthyroidism?

Many factors contribute to the development of hyperthyroidism. They include:

  • Graves’ disease
  • Multi-nodular goitre
  • Solitary thyroid nodule
  • Thyroiditis
  • Iodine induced i.e. due to excessive iodine
  • Taking large doses of thyroid hormone
  • Untreated hyperthyroidism can lead to high blood pressure heart failure, and thyroid storm.
Causes of hyperthyroidism

What are the Symptoms of Hyperthyroidism?

Symptoms of hyperthyroidism include:

  • Goiter or an enlargement of thyroid gland in the neck.
  • Weight loss despite increased appetite.
  • Nausea and vomiting
  • Diarrhea
  • Breathlessness on exertion
  • Emotional liability
  • Increased sweating
  • Heat intolerance
  • Loss of hair
  • Menstrual disorders
  • Exophthalmos - A condition when the eyes have a straight look protruded unusually out.
  • Fatigue
  • Rapid or irregular pulse
  • Palpitations
  • Sleeping difficulty
Symptoms of hyperthyroidism

How Do You Diagnose Hyperthyroidism?

Physical examination of the patient reveals:

  • Enlarged thyroid gland
  • Increased heart rate
  • Elevated systolic blood pressure

Clinical diagnosis does help, but biochemical diagnosis is confirmatory.

Blood hormone levels of T3 and free T4 are elevated. The thyroid stimulating hormone (TSH) level is usually low.

Diagnosis of hyperthyroidism

How Do You Treat Hyperthyroidism?

Thetreatment of hyperthyroidism depends on the cause and the severity of symptoms. Hyperthyroidism can be treated with one or more of the following:

  • Anti-thyroid drugs work best when the symptoms of hyperthyroidism are mild. These medicines do not always work. The patient has to take them at the same time every day. If they stop working, radioactive iodine is the next option.
  • Radioactive iodine is a common treatment and most people are cured after taking one dose. It destroys part of the thyroid gland and stops the excess production of hormones, but does not harm any other parts of the body.
  • Surgery to remove the thyroid gland. However, the patient is required to take thyroid hormone replacement pills for life time.
Treatment of hyperthyroidism

Hyperthyroidism During Pregnancy

Human chorionic gonadotropin (HCG) hormone is produced during pregnancy. This hormone is detected through pregnancy tests. HCG hormone has mild thyroid stimulating effects as a result can cause some symptoms of hyperthyroidism.

Hyperthyroidism occurs in 10-20% of normal pregnant women.  Pregnancies complicated by uncontrolled hyperthyroidism may result in a higher incidence of:

  • Spontaneous abortion
  • Preterm labor
  • Low birth weight babies

How do You Prevent Hyperthyroidism?

Iodine intake in the form of supplements and foods should be avoided as it can worsen hyperthyroidism. Vitamin B12, zinc and iron-rich foods should be included in the diet because people with hyperthyroidism are more likely to suffer from these nutrient deficiencies. Excessive weight loss can be managed by taking protein rich foods such as salmon, nuts and legumes. When hyperthyroidism is not treated, it may lead to osteoporosis. Including calcium-rich foods such as dairy products can help prevent such complications. Following a healthy lifestyle by avoiding alcohol, quitting smoking and engaging in regular physical activities can help improve the overall health.


  1. Thyroid Function Tests - (

Latest Publications and Research on Hyperthyroidism


shubhra_goel Sunday, August 23, 2009

I am having TSH level of 0.01 and have been diagnosed hyperthyroid. My doc prescribed thyroxin 50 for 3 months, another doc says that throxin is used in hypothyroid only please suggest whether i can take thyroxin 50 or not?

shubhra goel
36 yrs

mymoms Friday, June 5, 2009

any mediclaim policies for preexisting disease thyroid

S.C.L Saturday, May 30, 2009


S.C.L Saturday, May 30, 2009

what is making my hair come out by handfuls so all of a sudden?

popeye Wednesday, February 11, 2009

is depression and anxiety also a symptoms of hyperthyroid? also memory loss like forgetfulness...

manju.dongre Friday, December 5, 2008

what is the diet and excersice for hyperthiroid ?

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