Hyperthyroidism, also known as overactive thyroid, is a condition, in which thyroid hormones are produced in excess. The thyroid gland, situated in front of the neck produces two hormones, tri-iodothyronine (T3) and tetra-iodothyronine (T4). These hormones are mainly responsible for the metabolism in your body or simply said they control the way your cells utilize energy.


Thyroid gland and its hormones regulate cell metabolism. The excess production of T3 and T4 can speed up the body's metabolism and result in certain health consequences.

Causes Of Hyperthyroidism

Hyperthyroidism can be caused due to various conditions likes

  • Grave's Disease (Diffuse Toxic Goitre)– It is an autoimmune disorder, in which antibodies stimulate thyroid gland to secrete excess hormone and the entire gland becomes overactive and overgrown. It is more common in women. Some of the conditions that can trigger Grave's disease include certain infections, some medications, radiation to the neck region, smoking and stress.
  • Nodules - Hot nodule (Toxic adenoma)- In which one lump or nodule in the thyroid gland becomes dominant and independently, begins to secrete thyroid hormones. Plummer's disease (Toxic multinodular goitre), in which more nodules become overactive and secrete excess hormones.
  • Inflammation of Thyroid Gland (Thyroiditis) – This can occur during certain phases like viral infections or post partum period, causing inflammation of thyroid gland leading to excess secretion of thyroid hormones. In most cases, persons return to normal functioning thyroid after the phase passes.
  • Drug Induced - Excess intake of iodine, which is required to produce thyroid hormones, in patients with an underlying abnormal thyroid gland can cause overactivity. Excess doses in patients under thyroid hormone medication, dietary supplements with excess iodine, certain medications like amiodarone or imaging studies using iodine can contribute.
  • Pituitary Gland – Pituitary gland releases thyroid stimulating hormone (TSH) to control the production of thyroid hormones. Tumor of any other abnormality in pituitary gland that affects the functioning of TSH can cause over secretion of thyroid hormones.
  • Tumors of thyroid gland, ovaries or testes.

Symptoms of Hyperthyroidism

Clinical features of hyperthyroidism depend on the amount of thyroid hormones secreted in excess and are related to the increased metabolic rate. Patients with milder forms of hyperthyroidism may not show any symptoms, while others can have symptoms in varying degrees.

Some Of The Common Symptoms Of Hyperthyroidism Include:

  • Heat intolerance and excessive sweating
  • Irritability, increased anxiety and nervousness
  • Palpitations and increased heart rate
  • Swollen appearance of the neck due to enlarged thyroid gland
  • Increased or normal appetite but losing weight
  • Muscles weakness, fatigue and tremors
  • Changes in bowel movements, increased bowel frequency or diarrhea
  • Irregular menstruation or reduced menstrual flow
  • Decreased concentration and sleep disturbances
  • Itching on skin and brittle hair with increased hair fall
  • Eye complaints and vision disturbances

Grave's Ophthalmology - Vision disturbances may sometimes be seen in some patients, which are caused due to excess swelling of the muscles and tissues behind the eyes. This results in protrusion of the eyeballs out of their orbits. This presents as:

  • Red swollen eyes
  • Protruded eyeballs
  • Irritation or discomfort in eyes with excess tears
  • Inflammation of eyes and reduced eye movement
  • Double vision, increased sensitivity to light (photophobia)

In some severe conditions, irregular heart rate, shortness of breath or dizziness can occur which may need immediate medical attention.

Diagnosis of Hyperthyroidism

The physician would initially perform the following tests to diagnose Hyperthyroidism:

  • Clinical Examination – To observe thyroid gland and find related signs like increased reflexes, tremors, skin and eye changes.
  • Blood Tests – To detect levels of TSH and other thyroid hormones T3 and T4. To detect blood cholesterol and triglyceride levels

In order to find the exact cause of hyperthyroidism, some additional tests may be ordered

  • Radioactive Iodine Uptake Test – To detect the way thyroid gland takes in and absorbs the orally given iodine dose and uses it to produce thyroid hormones. Conclusions are drawn based on the results obtained in this test.
  • Thyroid Scan – A dye-injection or oral iodine dose test that enables visualization of the thyroid gland, which is seen on a computer. It helps to detect whether a region of the thyroid gland or the entire gland is affected.
  • Ultrasound Scan – To detect the enlargement of thyroid gland and surrounding structures.
  • CT or MRI Scan – Scanning specified region if tumor is suspected.

Treatment of Hyperthyroidism

Treatment mainly aims at reducing excess thyroid hormones and controlling the related symptoms.

  • Anti-Thyroid Medications– These drugs prevent thyroid hormone production.
  • Radioactive Iodine– Oral doses of radioactive iodine are given, which destroy the thyroid hormone producing cells. It slowly causes the gland to shrink and reduces the thyroid activity.
  • Symptomatic Treatment– This depends on the existing symptoms and medications are decided based on the patient's age, other illnesses, cause and extent of hyperthyroidism. Medications like beta-blockers are generally used to treat increased heart rate.
  • Surgery– In some cases, surgical removal of a part of the thyroid gland may be considered. Sometimes, particular surgical treatment like eye muscle surgery, orbital decompression surgery for Grave's disease may also be considered.

Prevention of Hyperthyroidism

Patients being treated for hyperthyroidism need to follow-up with the physician for regular monitoring. For weight loss, fatigue and other complaints a proper nutritional plan is essential. To prevent further weakness, bone thinning and to maintain good health, it is necessary to follow a proper diet plan and healthy routine as advised by the physician. Taking calcium and vitamin D supplements may be considered with medical advice. Regular exercise can help to improve bone and heart health.

For those suffering from eye disturbances or Grave's ophthalmology, special care of the eyes can help. Some measures include wearing sunglasses, applying cool eye compresses, using lubricating eye drops and raising the head while sleeping to relieve pressure on the eyes.

Written, Edited or Reviewed By:


Last Modified On: May 2, 2016

Pain Assist Inc.

Pramod Kerkar
  Note: Information provided is not a substitute for physician, hospital or any form of medical care. Examination and Investigation is necessary for correct diagnosis.

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