Q: Why don’t you ever write about thyroid disease? I know kids still have diseases of that gland – aren’t they important?
A: The thyroid gland is extremely important, as important as a car’s gas pedal. A car won’t go without pressure on the gas; a body won’t go without thyroid hormone, the chemical output of that butterfly-shaped gland in the neck.
Perhaps I haven’t written about it often because thyroid problems are relatively uncommon and are usually relatively easily managed.
Recently, a pediatric endocrinologist wrote a historical review of thyroid disease in the newborn, noting that at the turn of the twentieth century, a fair number of American children were born with severe signs of thyroid deficiency.
In fact, in 1900 it wasn’t known that those short, squat little babies and young children had lacked thyroid hormone, almost all of them because their mothers had not had enough iodine in their diets. Iodine is an essential ingredient in manufacturing thyroid hormone. These children, usually severely mentally retarded, were called cretins; one of the meanest and most prevalent names we used to insult one another in my youth was “you cretin!”
There are at least two reasons why this epithet and, more importantly, this condition, have almost vanished from the United States: most important is the routine supplementation of salt with iodine (don’t succumb to a fad for non-iodine-containing salt!), and the other near-universal screening of newborns for thyroid deficiency. In the past in the U.S. – and still in many areas in the developing world, mothers got insufficient iodine in their diets, resulting in inadequate manufacture in mother and fetus of thyroid hormone. No gas pedal.
Now that we all get iodized salt, iodine-deficiency is no longer a cause of “cretinism” here. Other causes of thyroid deficiency, such as abnormalities in thyroid chemicals in individuals are picked up through that poke in the heel that children around the country get, testing for some 27 serious diseases, before leaving the hospital after birth and about two weeks later.
Later in life, thyroid problems are less serious in the sense that they don’t cause life-long developmental problems, but they can play havoc with life as we know it. Think again of that gas pedal: Let’s suppose that there’s something wedged under it to keep you from pressing it down more than half an inch. The car may go, but it won’t go very fast.
Likewise with the thyroid-hormone-deprived body: everything slows down, including thinking, bowel activity (resulting in constipation) and heart rate. Without enough thyroid hormone, people are easily fatigued. I can’t think of a proper analogy to a car for the depression, weight gain and skin dryness that go along for the ride. Most weight gain, most fatigue and most depression are not related to thyroid disease, but physicians have to consider them as a possible cause of each.
Let’s suppose, then, that the gas pedal gets stuck down. That has happened to me – it was terrifying! It was all I could do to keep the car from careering into a building or an oncoming car. The analogy applies to thyroid hormone too; if you have too much of it, your body races, sometimes with dangerous consequences. The heart speeds up, thoughts tumble one over another, you burn lots of fuel (that is, you lose weight).
Hyperthyroidism is sometimes accompanied by changes in the appearance too: the eyes bug out (the scientific term is exophthalmos), due to swelling of the tissue in the eye socket behind the eye. Exophthalmos can be a problem on its own, causing eye dryness and double vision, but it is usually most important as a signal that the thyroid gland is overdoing its function, producing thyroid hormone.
Thyroid disease is sometimes passed on from parent to child. The thyroid gland requires not only iodine but also a number of enzymes to make its product, thyroid hormone. Occasionally one of those enzymes is missing, and thyroid hormone is either absent or defective and non-functional. This relatively uncommon situation is present at birth.
Not uncommon, however, is another genetically-related thyroid disorder, Hashimoto’s thyroiditis. If your sister (thyroiditis is much more common in females than in males) or brother has had Hashimoto’s disease, your risk is about 20 times higher than others’.
Now that iodine deficiency is rare in our part of the world, Hashimoto’s disease is the most common cause of an enlarged thyroid, causing a swelling in the neck called a goiter. The goiter may cause no problems initially, or it can be associated with either too much or too little thyroid hormone output. In those cases where there’s too much thyroid output, it’s usually like getting the gas pedal stuck down and then running out of gas – the eventual outcome is hypothyroidism, insufficient thyroid hormone.
Fortunately, thyroid problems are often both easily tested for and treated. Most medical laboratories do a lot of thyroid tests because thyroid problems are suspected in so many clinical situations – depression, fatigue, hyperactivity, dry skin, constipation among them. In the absence of adequate thyroid hormone output (too little or none at all), the hormone can be given by mouth, usually as thyroxine. Hyperthyroidism and exophthalmos are less common, but more difficult to treat.
I hope your children’s thyroid gas pedals are well-calibrated. Life, like driving, is much more difficult without a good accelerator.