Hyped up? Slowing down? The butterfly-shaped gland in your neck could be to blame, explains Mel Wynne-Jones
We don’t usually notice the butterfly-shaped thyroid gland at the front of our necks.But it’s the body’s pacemaker, producing thyroid hormone (thyroxine) to regulate the activity of every body cell- so it makes more thyroxine if we don’t have enough, and switches off when there is enough. Thyroid problems are common, can run in families and are often linked to immune disorders such as diabetes.
Rare causes include disorders of the brain’s pituitary and hypothalamus glands which monitor and regulate thyroxine and other hormones.
An underactive thyroid affects up to one in 50 women and one in 500 men, but there may be five times as many who have ‘subclinical’ (undetected) hypothyroidism.
It’s more common from midlife onwards, but can also be congenital or develop in pregnancy (affecting the baby). It’s also more common where diets are deficient in iodine, a vital component of thyroxine; drugs suchas lithium and amiodarone can also interfere with iodine metabolism.
Hypothyroidism can also develop in Hashimoto’s thyroiditis, an inflammatory immune disorder that produces a tender goitre (swelling), or after treatment for an overactive thyroid (hyperthyroidism).
Symptoms include tiredness, weight gain, feeling cold, skin, hair and nail changes, constipation, heavier periods, hoarseness, libido and memory problems.
These often develop gradually, or are mistaken for ageing or other conditions; untreated they can eventually lead to heart failure and dementia. But hypothyroidism quickly improves with thyroxine replacement tablets, although some changes take months to settle; you’ll need lifelong checks.
Thyrotoxicosis can also cause fatigue and weight loss or gain (increased appetite), but in contrast to hypothyroidism, can cause sweats, palpitations, shakiness, diarrhoea, scanty or absent periods, hair loss, mood and sleep disturbance.
It’s 10 times more common in women (one in 2,000), and can also be subclinical or develop in pregnancy. The most common form is Grave’s disease which often triggers staring, red, inflamed eyes and sight problems; inflammation (thyroiditis) and thyroid nodules can trigger it, too.
‘Over-revving’ the body can lead to heart failure and organ damage.
Drugs such as carbimazole are used to block the thyroid, sometimes completely (with ‘add-back’ thyroxine). These require careful monitoring; meanwhile, tremor and palpitations can be slowed with beta-blocker drugs.
But you may need surgery to remove part or all of the gland or nodule, or a drink containing a small amount of radioactive iodine to destroy your thyroid. These treatments can eventually lead to hypothyroidism.
A soft swelling is quite common and may be ignored if tests are normal; Hashimoto’s feels harder and/or tender.
Thyroid nodules (single lumps) may be easily felt or accidentally detected on a scan performed for other reasons; they’ll require treatment if they’re cancerous (rare) or benign adenomas producing toomuch thyroxine.
7 Tests you may need
1. Blood thyroxine (T4) level to see whether your thyroid is producing too little or too much. Occasionally another hormone, T3/triiodothyronine, is also tested.
2. Blood thyrotrophin stimulating hormone (TSH) – this increases when the pituitary is trying to stimulate the thyroid gland, or is abnormal.
3. Referral to an endocrinologist (hormone specialist) and possibly an eye specialist if you have hyperthyroidism or are pregnant.
4. An ultrasound, CT, MR or radionuclide scan to assess neck lump/swellings.
5. A heart tracing and ultrasound scan (ECG and echo) to check for signs of heart strain.
6. A brain scan to check your pituitary and hypothalamus.
7. Blood and other tests to look for other causes/linked conditions.