Thyroid diseases

What is the thyroid?

The thyroid is a gland in your neck, near the base of your throat.

The thyroid gland makes hormones that help control many of your body’s metabolic processes, such as:

• heart rate
• blood pressure
• body temperature
• weight

What types of thyroid problems are there?

There are several conditions that can affect your thyroid gland. Because your thyroid gland plays an important role in controlling many of your body’s functions, serious health problems can result when it is not working as it should.

Some thyroid problems cause an enlarged thyroid (goitre).

Hyperthyroidism

Hyperthyroidism is when your thyroid is overactive and makes too much thyroid hormone.

Symptoms of hyperthyroidism include:

• feeling anxious or nervous
• being unable to tolerate heat
• having heart palpitations
• losing weight, even if you’re eating the same amount of food

The effect of too much thyroid hormone on your body is sometimes called ‘thyrotoxicosis’.

Hypothyroidism

Hypothyroidism is when your thyroid is underactive and doesn’t make enough thyroid hormone.

Symptoms of hypothyroidism can be quite varied. They can include:

• fatigue (tiredness)
• being unable to tolerate the cold
• constipation
• dry skin
• weight gain
• poor memory or concentration problems
• depression

What causes thyroid problems?

Problems with the thyroid can be caused by:

• iodine deficiency
• autoimmune diseases — when your immune system attacks your thyroid — such as Graves’ disease or Hashimoto’s disease
• inflammation (thyroiditis), which may or may not cause pain
• nodules, or non-cancerous lumps
• thyroid cancer
• certain medical treatments — including radiation therapy, thyroid surgery, and some medicines

Occasionally, pregnancy can cause thyroid problems to start or get worse. If left untreated, this can cause problems for you and your baby, such as:

• miscarriage
• premature birth
• low birth weight
• problems with your baby’s brain development

If you’re pregnant or planning to become pregnant, talk to your doctor about your risk of having a thyroid disorder.

When should I see my doctor?

If you think you may have a thyroid problem, it’s important to see your doctor.

See your doctor if you have:

• symptoms of an overactive thyroid
• symptoms of an underactive thyroid
• a lump or swelling in your neck
• concerns about your risk of thyroid problems during pregnancy

What are the complications of thyroid problems?

If you have a thyroid problem that is not treated properly, serious health complications can result.

An enlarged thyroid, or goitre, may cause problems with swallowing and breathing.

Graves’ disease can cause eye and skin problems.

An overactive thyroid can lead to problems including:

• heart problems, such as rapid heart rate, problems with your heart rhythm (such as atrial fibrillation) or heart failure
• loss of bone density (osteoporosis)

An underactive thyroid (hypothyroidism) can cause complications such as:

• high cholesterol
• high blood pressure
• heart problems

Complications that need immediate medical attention

Thyroid storm is a severe excess of thyroid hormone. Symptoms can include:

• fever
• rapid heart rate
• vomiting
• delirium

Myxoedema coma is a rare, life-threatening condition caused by untreated, severe hypothyroidism. It causes:

• drowsiness that can lead to unconsciousness
• slow breathing
• low body temperature