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It could still be your thyroid

Case Report by Dr Peter Baratosy MB BS FACNEM

A new patient comes to see me. She is over-weight, tired, cold. No matter what she does – she continues to put on weight. She is tired all the time, is sleeping too much. She is constipated, dry skin, dry hair, losing hair. She has cold hands and feet. She has a strong Family History of Hypothyroidism – underactive thyroid. She has seen her local GP and all tests are normal.

She has done her reading on “Dr Google” and she has all the signs of Hypothyroidism. She sees her doctor again to complain – but the doctor says it is not hypothyroidism because her thyroid tests are normal. The doctor suggests that she is depressed and offers a prescription for anti-depressant medication.

A similar scenario happens when a person is diagnosed with Hypothyroidism, treated with the standard replacement therapy – Thyroxine – but they protest that they still do not feel well. They complain to their doctor but they are dismissed because the blood test has now become normal.

The job of the doctor is to get the patient better, not only to get the blood test better.She is not happy with this and then comes to see me. I listen to her story – she is very happy because I listened. I tell her that it could still be hypothyroidism because of all her symptoms… remember the old saying…If it walks like a duck and looks like a duck and quacks like a duck – then it is a duck!!”

How can I diagnose hypothyroidism – when the blood tests are normal – well at least in the normal range? Note that the “normal range” is quite broad and perhaps for this individual –may require the level to be at the high end. Hypothyroidism had been diagnosed since it was first described in the 1800s and was diagnosed on clinical grounds without any blood tests.

How can I justify the diagnosis of hypothyroidism with a normal blood test? We should ask ourselves - what does a Thyroid Function Test (TFT) really test for? All the test does is measures the amount of thyroid hormone floating in the blood. So from this we can say – yes, your thyroid is working normally – there is enough hormone floating in your blood.

So in a way – using a car analogy, the TFT is a petrol gauge. It tells us how much petrol is in the tank. Imagine you are driving your car down the road, the engine starts to splutter and then the engine conks out! Initially you think you have run out of fuel – but your petrol gauge shows you have plenty of fuel. The car has the signs and symptoms of running out of fuel but the petrol gauge shows a near full tank. Just like a person who has the signs and symptoms of hypothyroidism – yet the blood tests are normal.

In the car there must be a blockage somewhere – blocked fuel line, a defective fuel pump, dirt in the carburettor, etc.

So if the TFT is normal and the symptoms are that of hypothyroidism – where is the blockage?

The thyroid is making the hormone but the body is not using it – a peripheral blockage at some point. This can also happen when people are put on thyroid replacement – Thyroxine. Thyroxine (T4) is NOT the active hormone…. It is an inactive Pro-hormone. It needs to be converted to the active form Triiodothyronine – or T3. T4 is converted to T3 with an enzyme called 5’deiodinase. This enzyme is a Selenium dependant enzyme. The incidence of selenium deficiency is significant especially in Australia.

Another essential nutrient for thyroid is iodine – and Tasmania is known to be iodine deficient.

Also Vitamin D is needed for thyroid function – and again Tasmania is known for its high level of Vitamin D deficiency. There is also a sub group of people who have a genetic mutation in the 5’deiodinase enzyme – so the conversion of T4 to T3 is reduced. There is a problem with converting the pro-hormone to the active form.

Another cause of hypothyroid symptoms in a person with normal TFT is where there is peripheral blockage of the T3 receptor. There is controversy in the role of reverse T3 (rT3) – this may block peripheral T3 receptors. What is more accepted is that rT3 can block the conversion of T4 to T3.

Where does rT3 come from? rT3 is formed under the influence of stress and high cortisol levels. And who isn’t stressed in this modern society we live in. So, to treat, we need to look at the person’s stress levels, life style, diet, and provide nutrients and other substances to help the thyroid and to help the body use the hormones the thyroid is making.

Please call Reception on (03) 6224 6717 if you wish to make an appointment with Dr Peter Baratosy.


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