Overview

What is Hypothyroidism (Underactive Thyroid)?

Hypothyroidism (underactive thyroid) occurs when your body doesn’t produce enough thyroid hormones or when the body is not efficiently using thyroid hormone. It affects women more frequently than men. It commonly affects people over the age of 60 years old, but it can begin at any age.

Hypothyroidism can take several forms, including:

• Hashimoto's thyroiditis: this is the most common type of hypothyroidism. This is an autoimmune response in which antibodies in the blood destroy tissues in the thyroid gland. As a result, the thyroid decreases in size and reduces its production of thyroid hormones.

• Post-therapeutic hypothyroidism: results from the treatment of hyperthyroidism with radioactive iodine or surgical removal of part or all of the thyroid gland. The treatment can leave the patient's thyroid unable to produce sufficient amounts of thyroid hormone.

• Goitrous hypothyroidism: results from an extreme shortage of iodine in the diet, producing a goitre in the neck. It is relatively rare in the Western world due to the introduction of iodised salt.

Symptoms

What are the signs of Hypothyroidism (Underactive Thyroid)?

The signs and symptoms of hypothyroidism may vary from person to person. The severity of the condition also affects which signs and symptoms appear and when. The most common signs and symptoms of hypothyroidism include:

Weight gain

Weight gain

Slow heart rate

Slow heart rate

Fatigue

Fatigue

Hoarse voice

Hoarse voice

Puffy face

Puffy face

Thinning of eyebrows from the outsides

Thinning of eyebrows from the outsides

Dry, thinning hair

Dry, thinning hair

Drooping eyelids

Drooping eyelids

Intolerance to cold

Intolerance to cold

Constipation

Constipation

Depression

Depression

Dry, scaly, thick, coarse hair

Dry, scaly, thick, coarse hair

Raised, thickened skin over the shins

Raised, thickened skin over the shins

Muscle weakness

Muscle weakness

Impaired memory

Impaired memory

Menstrual cramps

Menstrual cramps

Pain and stiffness in your joints

Pain and stiffness in your joints

Fertility difficulties or menstrual changes

Fertility difficulties or menstrual changes

Causes

What are the causes of Hypothyroidism (Underactive Thyroid)?

When your thyroid doesn't produce enough hormones, the balance of chemical reactions in your body can be upset. There can be a number of reasons why this may occur, including:

Autoimmune disease

Autoimmune disease

Hyperthyroidism treatments

Hyperthyroidism treatments

Radiation therapy

Radiation therapy

Thyroid surgery (removal)

Thyroid surgery (removal)

Certain medications

Certain medications

Diagnosis

How do I know if I have Hypothyroidism (Underactive Thyroid)?

To diagnose hypothyroidism, your doctor may assess your symptoms and perform any of the following tests:

Thyroid Function Tests

Thyroid Function Tests

Find a Practitioner

See a list of practitioners who specialise in treating Hypothyroidism (Underactive Thyroid)