Iodine deficiency disorders are of great concern because they have a brutal impact on up to a quarter of the world’s population, however fortunately it is one of the easiest of the most common deficiencies to control. Iodine deficiency disorders manifest in several forms, depending on the time of onset. When a fetus is deprived, it often results in cretenism or mental retardation. Children without iodine often suffer from retarded physical growth and intellectual development, as well as from goitre. Adults suffer from goitre and sometimes stillbirth or spontaneous abortion in pregnant women. Those outcomes that are visible, such as goitre and cretenism, are easily detected clinically and are use diagnostically for IDD. The subtler effects that come from deficiencies, such as slightly enlarged thyroid gland, hindered psychological development, stillbirths, and spontaneous abortions are less easily detected or attributed to IDD.

Enlargement of the thyroid gland, or goitre, is the most frequent and obvious manifestations of iodine deficiency. It usually results from less that 50 ug of intake per day iodine (in adults), in which case the thyroid gland begins to enlarge to compensate for the iodine uptake by increasing surface volume. Goitre are especially seen in school age children because of the increased need for thyroxine (hormone produced by the thyroid that contains iodine) to regulate metabolism and growth. For this reason, school age children are usually the first survey group used to assess IDD in the population through goitre detection.

CLINICAL INDICATORS:

Goitre
Cretenism

Goitre is measured through physical examination, usually both visibly and by palpitation. Through visual examination, the goitre is marked as being visible in normal position or with head titled back. Through palpitation, the goitre is examined from the front at eye level using the thumbs on either side of the gland in the neck to judge the size and classifying it based on the WHO recommended system, which has been simplified to include only 3 grades.

• Grade 0 is not palpable or visible,
• Grade 1 is palpable but not visible when the neck is in normal position,
• Grade 3 is visible in normal position and consistently palpable

Because clinical signs, especially goitre, are so routinely used to monitor IDD, rarely is does one see the use of sub-clinical indicators in large surveys. Even so, one sub-clinical indicator, urinary iodine, is available for use on an individual basis and occasionally used in surveys. Because this test is not often available at district or regional hospitals, obvious limitations exist.