Feeling tired? Have you ever had a thyroid function test? An underactive thyroid is a common cause of tiredness, and one of the first things investigated when patients visit their doctors complaining of tiredness.


The endrocrine system encompasses all of the body’s hormones, which are the chemicals popularly recognised as playing a role in turning children into adults by way of puberty. In fact, hormones are ‘chemical messengers’ which travel in the bloodstream and they are actually very important throughout our lives, every day of our lives! They are constantly zipping around the circulation, telling different parts of the body what to do and when to do it. We’d all be lost without them!

There are some celebrities of the hormone-world which are better known to the public. These are testosterone and oestrogen, and they are probably more exciting to hear about because they are, quite literally, sexy.

Meanwhile, the humble hormones produced by the thyroid gland, the so-called thyroid hormones, are rather more obscure. But one must not mistake these hormones’ lack of fame for lack of importance, as they are in fact amongst the most influential hormones we produce. Accordingly, an excess of thyroid hormones (known as hyperthyroidism), or else a paucity or even absence of thyroid hormones (known as hypothyroidism) can have significant and serious impacts on health.


What Is The Thyroid?

The thyroid gland is a butterfly-shaped gland found in the neck. In men, a handy sign-post of its lair is the Adam’s apple, which sits just above it. In good health, the brain is always silently speaking to the thyroid, sending it whispered instructions to either dial up or dial down output of the thyroid hormones. Of particular significance are the thyroid hormones triiodothyronine and thyroxine, which can be referred to as T3 and T4, respectively.


Did you know where the thyroid gland is located? Most people don't!


What Do Thyroid Hormones Do?

Once they have been produced by the thyroid, T3 and T4 are then released into the circulation, where they travel around the body eliciting effects in a wide range of body parts, including the brain, the liver, muscle and fat.

These effects are perhaps too numerous to be listed, but they can be summarised as processes important for:

  • Metabolism
    • By which food is converted into energy
  • Growth

An important part of this picture are the effects of T3 and T4 on the heart: under their influence, the heart works harder – it increases the speed and force of its beats. The role of the thyroid hormones in maintaining normal sleeping patterns is also important to recognise.

That the thyroid hormones are able to provoke so many effects in such different parts of the body gives us a clue as to why the symptoms that then arise in thyroid disease are so various and, in some cases, so subtle…


Thyroid hormones also play an important role in regulating sleeping patterns


Hyperthyroidism | Overactive Thyroid

Causes of an Overactive Thyroid

Thyroid hormone levels may be raised due to a number of reasons. The most common cause is Graves’ disease, which accounts for two-thirds of cases.

Typically affecting women, although can also affect in men, Graves’ disease occurs when the body’s own defence mechanism against bugs and other nasty things, known as the immune system, mistakes the thyroid gland for being something that needs getting rid of. The resulting damage causes the thyroid to begin to produce thyroid hormones at levels above normal. Due to this, lots of the processes in the body which are controlled by the thyroid hormones begin to speed up, and hyperthyroidism results.

The growth of lumps on the thyroid is another cause of hyperthyroidism. The extra thyroid tissue that these lumps consist of may contribute to the amount of thyroid hormone being produced, pushing levels above normal. It is important to realise that the occurrence of thyroid lumps is not always indicative of thyroid cancer.


Symptoms of Overactive Thyroid

These include but are not limited to:

  • Difficulty sleeping
  • Weight loss
  • Increase in appetite
  • Increased heat production
  • Increased sweating
  • Heart palpitations
  • Swelling in the neck that doesn’t go away 
    • Known as Goitre
  • Increased anxiety and irritability
  • Emotional instability, which may register as ‘mood swings’
  • Diarrhoea
  • Thinning of hair


Complications of Hyperthyroidism

Hyperthyroidism may sometimes be associated with symptoms in the eye. These may include increased tearing and ‘grittiness,’ bulging of the eyes so that they might look as if they are popping out of their sockets, and double vision. These symptoms are indicative of a condition called thyroid eye disease, which occurs in up to half of people with Graves’ disease.

Hyperthyroidism may also be the cause of problems in pregnancy, and so women with diagnosed hyperthyroidism should be sure to seek advice from their doctor if they are planning to start a family.

Finally, under extreme circumstances, people with hyperthyroidism may suddenly become very unwell and require emergency care. However, if their hyperthyroidism is diagnosed and properly treated and managed, then this state of sudden serious illness, often referred to as a thyroid storm, should usually be avoidable.


Thyroid conditions may be complicated by pregnancy, so must be monitored closely by a doctor throughout pregnancy


Hypothyroidism | Underactive Thyroid

Causes of an Underactive Thyroid

Hypothyroidism occurs when the output of thyroid hormones from the thyroid gland is below normal levels. This causes processes which are affected by the thyroid hormones to slow down.

As with in hyperthyroidism, output from the thyroid gland may become compromised when the immune system gets confused and mistakenly attacks the thyroid, with many cells of the immune system, called lymphocytes, rushing into the gland. In this particular type of thyroid immune attack, the effect is that thyroid hormone output is significantly decreased. Women primarily are the sufferers of hypothyroidism, although hypothyroidism may also affect men.


Thyroid diseases are more common in women than men


Symptoms of Hypothyroidism

These include but are not limited to:

  • Increased tiredness and sleepiness
  • Feeling of lethargy
  • Weight gain
  • Increased sensitivity to the cold
  • Dry skin
  • Muscle ache and cramps
  • Depression
  • Constipation


Complications of Hypothyroidism

Like hyperthyroidism, hypothyroidism can cause problems in pregnancy, and so a doctor’s advice must always be sought when planning to become pregnant.

Other serious complications of hypothyroidism include heart disease and, in the long term, dementia. However, these should usually only occur in the absence of correct diagnosis and proper treatment.

Very rarely, and usually only when proper treatment has been absent, hypothyroidism may manifest as a sudden, life-threatening condition called myxoedema coma.


The main symptom of an underactive thyroid is excess tiredness


Thyroid Screening: Tests and Diagnosis

Problems of the thyroid gland can normally be discovered quite simply, by use of a blood test! Levels of the thyroid hormones may be looked at, as well as levels of the brain signal which causes the thyroid to make hormones in the first place.

If the doctor suspects that an immune attack on the thyroid is causing the disease, then they will also be organise a blood test to investigate. Different kinds of imaging, including ultrasound (the type of scanning used to monitor unborn babies in pregnancy) and a special type of scan called an isotope scan, may also be used to give the doctor more insight on the type of disease.


Thyroid Disease: Treatment and Management


Treatment for hyperthyroidism can be categorised into three groups: medication, radiation and surgery.

  • Medications that can reduce the amount of thyroid hormone being produced may be given. An example of such a medication is carbimazole. Beta blockers may additionally be prescribed in order to help control fast and irregular heartbeat.
  • Radiation is a method by which some of the thyroid gland may be intentionally destroyed, with the effect of reducing the amount of thyroid hormone that is be produced overall.
  • Surgery to remove the thyroid gland, either in part or in its entirety, may be advised.


People with hypothyroidism are primarily treated with hormone replacement therapy: a tablet medication called levothyroxine must be swallowed every day for the rest of the person’s life in order to ensure that low levels of thyroid hormones within the body are always topped up.

The dose of the medication is also checked on an annual basis by performing a blood test, to ensure you are on the correct dose.


Treatment for hypothyroidism is usually Levothyroxine, with doses tailored to the individual patient's need


Side-effects of Thyroid Treatment

Unfortunately, no treatment is perfect: treatment with medications is always associated with a risk of developing side effects, and radiation and surgery may cause people to go from being hyperthyroid to becoming hypothyroid. Therefore, there are some big decisions to be made in the treatment of thyroid disease, and patients should seek to receive the best possible advice from their doctor before making an informed decision about how they would like their condition to be managed.


So if you're experiencing any of the above symptoms, such as undue tiredness, why not book in for a same day doctor consultation to get your thyroid investigated? One simple blood test could reveal the answer to your fatigue, and effective treatment could have a really positive effect on your energy levels, and these are available at all 8 of our London clinics as one of our many GP surgery services. 


By Ava Zamani