Thyroid Hormone Problems
Hypothyroidism
Hypothyroidism - the underactive gland
In this condition the thyroid gland produces too little thyroid hormone. This condition is extremely common and affects women around ten times more often than men.
What are the causes of an underactive thyroid gland?
- Aplasia - failure of gland development, this leads to low levels of thyroid hormones in affected babies and may lead to mental retardation unless recognised and treated with hormone replacement.
- Iodine Deficiency – the thyroid gland lacks the building blocks to make thyroid hormones; this causes the gland to enlarge (a Goitre) and produces the symptoms of hypothyroidism if iodine levels are very low. In some areas of the world there is very little iodine in the diet and in these areas hypothyroidism and thyroid swelling are common (Endemic Goitre).
- Dyshormonogenesis – this means that the thyroid lacks the chemical enzymes to make thyroid hormones. This can be :
- Inherited – This may affect several generations of the same family leading to hypothyroidism and a goitre.
- As a result of some drugs e.g. amiodarone – These can interfere with hormone production and lead to hypothyroidism.
- Autoimmune Thyroiditis – This is the most common cause of an underactive thyroid gland. The immune system sometimes produces abnormal antibodies (thyroid auto-antibodies) which attack its own cells in this case cells in the thyroid gland. This can cause the gland to swell and eventually stop producing hormones
- Atrophic hypothyroidism
- Hashimoto’s Thyroiditis - This condition in its early stages may cause a mildly overactive thyroid gland. As it progresses it damages the gland and prevents it from making thyroid hormones resulting in hypothyroidism.
- Following thyroid surgery (Total Thyroidectomy) or other thyroid treatments e.g. Radio-iodine. Some of the treatments used for overactive thyroid glands and for the treatment of swollen or cancerous glands may prevent the gland from producing sufficient thyroid hormones.
What are the symptoms of hypothyroidism?
Thyroid hormones essentially control your metabolism. Too little thyroid hormone slows you down. This can make you feel lethargic and cause you to gain weight. Your hair may become thin . Your heart rate may become slow as may your movements and your reactions.
How is hypothyroidism diagnosed?
Your doctor will usually order a simple blood test called a Thyroid Function Test (TFT); they may also recommend measurement of thyroid autoantibody levels to see what may be causing the hypothyroidism. In hypothyroidism the tests would be expected to show
- Raised TSH
- Low T3, T4
- Auto-antibodies- raised levels of thyroid auto-antibodies may occur with autoimmune hypothyroidism (Hashimoto’s Thyroiditis).
Is there any treatment for hypothyroidism?
The treatment is usually straightforward. The most common treatment for hypothyroidism is Thyroxine (a synthetic T4 or thyroid hormone). It is given once daily as a tablet and the dose adjusted using the TSH level in the bloodstream as a guide.
Tips for Taking Thyroxine (Oroxine)
Often patients and doctors struggle to find the right dose of thyroxine for a particular patient. Sometimes this is because the patient is taking the right dose in the wrong way. Following these simple instructions should help to stabilise your thyroid hormone levels:
- Thyroxine (Oroxine) is taken as a tablet. It is taken once a day every day. Do not miss days except on the instructions of your doctor.
- Take your thyroxine after fasting for 4 hours, do not take any other food for at least 20-30 min.
- Avoid other drugs especially calcium carbonate (Caltrate) for at least 30 min before or after your Thyroxine.
- Fruit juices may interfere with thyroxine absorption.
So the best advice is to take your thyroxine when you wake up in the morning and don’t eat or drink anything except water for 30 minutes afterwards.