Hypothyroidism: Signs and Symptoms

In recent posts I have discussed what causes hypothyroidism in children and how to diagnose it but I didn’t really discuss typical signs and symptoms.

Newborns: don’t wait for clues

The majority of newborns with hypothyroidism have absolutely no signs or symptoms. That is why we have newborn screening for hypothyroidism. If there was severe prenatal hypothyroidism, a newborn might present with “classic” signs and symptoms that include hoarse cry, poor feeding, lethargy, constipation, enlargement of the tongue, and overall decreased muscle tone including an umbilical hernias. Lab tests would show very low serum free T4 and very high TSH (often as high as the lab assay goes, 200-300). Lab tests might also show hypoglycemia (low blood sugar levels) and hyperbilirubinemia, a high level of bilirubin in the blood. Bilirubin is a yellowish pigment found in bile and if elevated in the blood can cause the skin and whites of the eyes to take on a yellowish color called jaundice- almost all newborns have some degree of hyperbilirubinemia but it tends to be worse and last longer in hypothyroidism.

Children and adults with hypothyroidism can also have a yellowish tint to the skin due to high levels of carotene in the skin called hypercarotenosis. This is due to slow metabolism of the yellow pigment carotene, found in a variety of foods, particularly carrots. People who eat huge amounts of vegetables that contain carotene can have this yellow staining of the skin even if they do not have hypothyroidism. The pigmentation is harmless and will go away when hypothyroidism is treated (or the carrot-lover cuts back). One way to tell if a yellowish tint to the skin is due to hyperbilirubinemia (high bilirubin levels in the blood) or simply due to carotene in the skin is to look at the sclera (the whites of the eyes). If the sclera do not have a yellowish tint to them, it’s hypercarotenosis (you’ll be just as clever as Dr. House- the guy from the TV show called “House,” for those of you enlightened people who do not watch much TV).

Children: think poor growth and excellent school performance

In children, the signs and symptoms of hypothyroidism are similar to those in adults with one major exception, growth. Linear growth (growth in height) is markedly impaired in children with hypothyroidism (only if the free T4 level is low). In addition, these children may be overweight. It is interesting that school performance usually does not suffer; children with hypothyroidism have a much slower metabolism than normal and they are not very distractible- they can really concentrate on their schoolwork! In fact, one of the difficulties in treating children with longstanding severe hypothyroidism is that they can go from being the perfect child, quiet and well-behaved, to a hyperactive, highly distractible child. Thank goodness the hyperactive “phase” does not last forever, although the child may never go back to being so easy to deal with. I always warn parents about this temporary “side effect” of treating severe hypothyroidism in the hopes of avoiding telephone calls from angry parents asking what have I done to their wonderful child! Please note that this Jekyll and Hyde personality/behavior change occurs only when the hypothyroidism has been severe and longstanding.

Sometimes the diagnosis is delayed for quite a long time while doctors are trying to figure out why their patients have dry skin, anemia, constipation, and poor growth. In severe cases, the thyroid gland is usually not enlarged (it has been destroyed by the autoimmune process found in Hashimoto’s thyroiditis).

Adults with hypothyroidism

In adults, signs and symptoms are not really much different than those found in children. Of course, in adults one cannot assess linear growth as a clue to the disorder. Fatigue and weight gain are common but, unfortunately, most people with those symptoms do not have hypothyroidism. Remember it’s easy to tell from two simple laboratory tests, free T4 and TSH.

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