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Secondary Hyperthyroidism : Causes, Symptoms, Diagnosis, Treatment

What is Secondary Hyperthyroidism?

Secondary hyperthyroidism is a condition of the thyroid gland that can affect to a great extent. It is necessary to know the causes and symptoms of secondary hyperthyroidism to seek timely medical advice. Know the diagnosis and treatment of secondary hyperthyroidism to manage the condition well.

Thyroid gland forms an important part of the human endocrine system that is located right below the trachea in front of the neck. The gland is responsible for production of hormones namely:

  • Thyroxine or the T4
  • Triiodothyronine or T3

These help to regulate the body metabolism and for wellbeing. The release and levels of the two hormones is also controlled by a system involving hypothalamus and pituitary gland. If release of these hormones decreases by thyroid gland, it increases from the hypothalamus and pituitary gland and the vice versa is also true. Hence, this way their levels are balanced allowing optimum metabolism for the body. In addition, a hormone called calcitonin is also released by the gland that has a role to play in maintaining calcium levels in the body.

Secondary hyperthyroidism is a condition caused due to imbalance of thyroid hormones, secondary to other condition.

What is Secondary Hyperthyroidism?

Causes of Secondary Hyperthyroidism

The cause of secondary hyperthyroidism are often related to the glands secreting the hormones or other factors that affect the functioning of these glands and hormones. Some conditions that affect the metabolism of a person can increase the chances of secondary hyperthyroidism.

Some factors related to the causes of secondary hyperthyroidism include

  • Habitual smoking
  • Women are likely to suffer from it more than men.

The causes of thyroid disorders is malfunctioning of the gland or control disruption within the system involving hypothalamus and pituitary gland.

When the levels of T3 and T4 tend to increase more than the normal, it leads to hyperthyroidism. On the other hand, when the same hormone levels go down it leads to hypothyroidism.

Secondary hyperthyroidism is a condition that involves malfunctioning of pituitary gland releasing excess of hormones called:

  • Thyroid Stimulating Hormone (TSH)
  • Thyrotropin (TRH)

The main causes of secondary hyperthyroidism includes the development of a tumor around the area of pituitary gland or hypothalamus. Alternatively, radiations in the brain can also be responsible for the same.

Sometimes, excessive blood loss either during delivery can result in infections of the pituitary gland. Some chronic illness can also result in inflammation of the gland or could create iron deposits leading to secondary hypothyroidism.

Symptoms of Secondary Hyperthyroidism

Symptoms of secondary hyperthyroidism include

  • Rapid loss of weight that results due to increased activity of the thyroid gland thereby disturbing body metabolism.
  • High sensitivity to heat and lighting
  • Excessive sweating
  • Intestinal activity also increases leading to disorders such as diarrhea
  • Disturbed heartbeat and palpitations
  • Thinning of skin bones
  • Fatigue and tiredness
  • Shaking or tremors in fingers which get observed when hands are kept still

If the over activeness of thyroid gland is left untreated for a longer time, it could lead to high disturbances in blood pressure, heartbeat and pulse making the condition life threatening. It is also known as thyroid storm which can be fatal for the person.

Diagnosis of Secondary Hyperthyroidism

When a thyroid disease is suspected, the doctor can ask for several tests to determine the functioning of thyroid gland. The diagnosis of secondary hyperthyroidism is based on such tests. The tests are performed to determine the levels of hormones (TSH/T3 OR T4) secreted by the thyroid gland to determine the intensity.

If the levels of TSH are found to be low, that indicates a malfunctioning of thyroid gland which stops the secretion of TSH from the pituitary gland. T3 and T4 levels are also measured which further determine the severity of symptoms.

Ultrasound examination done by the doctor helps to determine the gland nodules. In order to examine iodine levels, a radioactive test is done that neglects the amount of iodine taken in by the gland from the bloodstream. These investigations can help in confirming the diagnosis of secondary hyperthyroidism.

Treatment of Secondary Hyperthyroidism

The cause of secondary hyperthyroidism is the malfunction of the thyroid gland to be able to release the right levels of hormone required for maintaining body metabolism. Hence, treatments for the same are aligned in resolving the issue with the gland.

Iodine Treatment

Iodine treatment for secondary hyperthyroidism may be considered, if the iodine levels within the gland are not balanced that can cause disturbed hormonal secretion. Hence, an iodine treatment is then followed to bring hyperthyroidism under control. However, it is only a short term treatment which requires further activities that can be effective in the long run.

Radioactive iodine can be used to keep a check on the symptoms of hyperthyroidism. However, the treatment can act contradictory leading to hypothyroidism in case too much of hormone is destroyed. That would require a mechanism for hormone replacement on a regular basis to control hypothyroidism.

The levels of iodine used have to be just adequate so that they do not cause damage to any other part of the body. Moreover, pregnant mothers are kept strictly away from the same as radioactive iodine can be dangerous and cause fetus destruction.


Medications that are to be taken orally are prescribed by the doctor to keep a check on the symptoms and to prevent them from getting escalated. The two major medications used in the treatment of secondary hyperthyroidism are:

  • Methimazole
  • Propylthiouracil

The right dosage of these medications is successful in bringing hyperthyroidism to control within 3 to 6 weeks. However, in case of severe symptoms, a larger dose could be prescribed, but that can have implications in the form of side effects. Some of the common side effects that can be a result of the medications are:

Beta blocker medications including propranolol are used in the treatment of hyperthyroidism symptoms like anxiety, palpitations and body tremors. But, these do not have any direct effect on the functioning of thyroid gland.

In extreme cases, a surgery is done to remove thyroid gland which poses a risk for occurrence of hypothyroidism. In that case, a hormonal replacement treatment is required on a lifelong basis for the patients to survive.

Till date, we do not have known methods that can be successful in preventing the disease. However, following a healthy lifestyle, being physically active and eating healthy food can help to maintain effective metabolism. Individuals who tend to find symptoms should strictly stay away from smoking and follow a regular exercise regime. They should not delay for seeking in medical advice as that could help in early diagnosis and treatment of secondary hyperthyroidism.


  1. Mayo Clinic – Secondary hyperthyroidism:
  2. Endocrine Web – Secondary Hyperthyroidism:
  3. American Thyroid Association – Hyperthyroidism (Overactive): Link

Also Read:

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:July 28, 2023

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