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Thyroid Diagnosis and Monitoring at Karanga Health Centre
When assessing your thyroid activity and monitoring your treatment to decide if
you are taking the right dose of thyroid hormone we look at
1) your symptoms (things you feel and notice eg level of energy)
You have a chart that it will be useful for you to use to record your symptoms
over time. Please keep a weekly record and bring it with you to your
appointments.
2) your signs ( things we can observe about your body eg your pulse rate)
Your doctor will keep a record of this.
3) Your test results
There are several blood, urine and other tests that we do when indicated. The
results of these will be discussed at consultations. There are 3 hormones in
particular that we monitor in the blood regularly: T4, T3 and TSH. None of the
tests on their own give a definitive answer as to whether we are giving you the
right amount of thyroid hormone. The level of hormones in your blood does not
necessarily correlate with the level of thyroid activity in your cells. This is because
there are thyroid receptors inside the cells which the thyroid hormone has to
combine with in order to make you healthy. There are varying levels of thyroid
receptors and we can’t measure them because they are outside the blood.
Therefore, your body is the best indicator of the level of thyroid activity and so we
place a lot of importance on what you and your body tell us.
Because the picture is complicated and because the doctors at Karanga Health
Centre sometimes make a decision about thyroid treatment which could be
different from the decision most other doctors in New Zealand would make, we
would like you to be informed about the thinking behind our decisions.
One divergence of opinion you may encounter relates to the level of TSH (Thyroid
Stimulating Hormone) in the blood. Frequently doctors use TSH alone to screen
for thyroid activity and to monitor the treatment. Karanga doctors consider this
inadequate for both purposes.
1) Diagnosis
If your TSH is too high it is an indication that you have low thyroid activity. Your
pituitary considers that the levels of thyroid hormone are low and it makes more
TSH to try and get your thyroid gland to make more thyroid hormones. The level
of TSH that is generally accepted in New Zealand as being too high and requiring
treatment is higher than Karanga doctors and other leading groups internationally
believe to be acceptable. Thus many hypothyroid patients go untreated and
undertreated. The consequences of this are enormous, given the widespread
effects of thyroid hormone in the body.
2) Monitoring
Sometimes when patients receive an amount of thyroid hormone that provides a
good level of T3 in the blood and the patient appears to be well with respect to
thyroid activity there is no TSH to be seen in the blood. Most doctors think it is
not good to have no TSH in the blood. There is some truth in this because TSH
does have a role to play in the body. But if the only way to have healthy thyroid
activity is to do without TSH then the choice should favour healthy thyroid
activity. This is because the role of thyroid hormone is known to be far more
important than that of TSH. Thyroid hormone drives your metabolism ie every
chemical reaction inside the cell is dependent on it. It helps glucose out of the
blood and into the cell independently of insulin and so low thyroid activity
contributes to the development of diabetes. It helps cholesterol to be
metabolized and made into your adrenal hormones, so low thyroid function
contributes to heart disease and adrenal problems.
TSH is made in the pituitary gland in the brain when the pituitary receives a
message that there is a need for thyroid hormone. It tells the thyroid gland to
make thyroid hormone. If your thyroid gland is not making enough thyroid
hormones anyway and we are supplementing your levels, then your TSH is of little
use in this respect. A low TSH has been associated with osteoporosis but this can
be avoided by having good levels of other hormones like estrogen and
progesterone which are even more important than TSH for maintaining bone
health. Low TSH has also been associated in elderly people with atrial fibrillation,
an irregular heartbeat. We can monitor your pulse to avoid this.
There seems no good reason to sacrifice thyroid health for TSH levels. This is the
opinion of many other doctors internationally with whom we have studied and
conferred. The International Hormone Society www.intlhormonesociety.org has a
section entitled “physician consensus” which includes a statement relating to the
management of low thyroid function. The consensus has been signed by many
hundreds of doctors internationally who agree with our thinking on this subject.