Medical Resources :: Common Diseases :: Dietary Deficiencies & Other Conditions :: Iodine Deficiency

With the increasing numbers of children adopted from abroad, parents and healthcare professionals must learn about medical issues in other countries. There are a number of medical concerns that are specific for children adopted from China. I will attempt to address these medical issues through an open forum in this newsletter. Parents and members of FCC should send suggestions to the newsletter. Susan Caughman suggested iodine deficiency for my first topic as there was an article in the New York Times, Tuesday, June 4, 1996 written by Patrick E Tyler featuring iodine deficiency in China.

Iodine is a trace element found in the soil, air, and sea; the only physiological importance of iodine is as an essential component of the thyroid hormones. Alteration in the function of the nervous system can occur due to iodine deficiency. The most severe form of iodine deficiency is cretinism which is the rare consequence of fetal/infant hypothyroidism.Iodine is ingested in food, water, and most commonly in industrialized nations, as iodized salt. In the 1920's the United States eliminated Iodine Deficiency Disorders (IDD) by iodizing salt.

Most iodine deficient areas in China are inland rural areas, plateau and mountain regions, and most of Mongolia and Tibet. There are actually few adoptions from Mongolia and Tibet. Most orphanages are located in areas within a few hours of cities where transport of iodized salt is actively underway. It is the inaccessible areas of China which have remained iodine deficient. Individuals living in coastal areas of China are protected because of ingestion of seafood including fish and seaweed which have high iodine content.

The prevalence of congenital hypothyroidism worldwide is 1 in 4,000 infants and the three major causes of hypothyroidism are #1 thyroid dysgenesis/ectopic thyroid (90%), #2 enzyme deficiencies (rare), and #3 iodine deficiency. Iodine deficient countries will have the same causes of hypothyroidism, but with increased numbers caused by iodine deficiency. Infants in orphanages in China usually receive formula that is milk-based and probably has enough iodine to prevent the severest form of iodine deficiency, cretinism. Congenital hypothyroidism from other than iodine deficiency is still a serious disease and can cause mental retardation and growth delay with permanent sequelac, if not diagnosed early in infancy. The dysgenesis/ectopia of the thyroid gland is still the most common cause of congenital hypothyroidism in any child in any part of the world.

In each state in the U.S. a metabolic screen is performed at 24 hours after birth. A heel stick is done and blood is placed on blotter paper which is then sent to the state laboratory. Blood samples are presently tested for disorders involving the metabolism of phenylalanine, leucine, methionine, galactose, and biotin. These metabolic disorders are rare. The blotter also tests for sickle hemoglobin, HIV antibody (7/1/96), and hypothyroidism.

All children who are adopted from China would probably benefit from a newborn screen when they arrive in the U.S. If the screen is not performed, then I would definitely recommend at least thyroid function tests, particularly thyroxine Cf 4) and TSH (thyroid stimulating hormone). Hypothyroidism can have a subde clinical presentation. Children with ectopic glands can do fine for a few years and then they may develop severe hypothyroidism with growth failure. A large open anterior fontanel, constipation, growth fai lure, and developmental delay are some of the signs of hypothyroidism.

Recently, I evaluated a newly adopted 8 month old Chinese infant. I sent the newborn screen and within two weeks I received a letter from the state indicating that the thyroxine Cf4) was low. She is cuirently being evaluated for possible thyroid replacement therapy. I prefer to do the metabolic screen. It is free and it requires only a 0.5 ml sample of blood. It can easily be done when other blood is drawn in the initial evaluation of the child. Abnormal results are communicated to pediatricians by phone or by letter depending on the urgency involved.