Cretinism, subclinical

Besides the typical clinical cretin, we have found a subclinical type of cretin in various endemias in China. The characteristics of the "subcretin" are summarized and the diagnostic criteria as well as the method of assessment discussed in detail. 

These criteria were summed up from our experiences in the neurological cretin endemias. Because the clinical type of the myxedematous cretin is so different from the neurological cretin, we could presume that the subclinical type of the myxedematous cretin should be different to a similar degree. 

Because of the lack of definite diagnostic criteria and the fact that large scale epidemiological surveys are quite rare, data concerning the relative frequency of endemic cretinism and subcretinism are also varied. We have found in a relatively precise survey in a severe endemia the cretin incidence is 2.56% and that of subclinical individuals 14.8%. 

The epidemiological data presented here confirm the existence of subclinical abnormal individuals in IDD endemias and show the numbers may be many times more than the cretins. Like an iceberg on the sea, the clinical cases seem to be the above-the-sea-level part but the iceberg under the water is much bigger. They are not so miserable for the family as is the cretin. Yet by their large numbers, they may give a very heavy burden to the community and hinder the socio-economic improvement of China. 

There is a spectrum of Impairment ranging from death through clinical endemic cretinism and subclinical deficits of motor and cognitive performance, to normality. This spectrum of effects appears to be associated with maternal thyroxine during pregnancy. No association with maternal triiodothyronine was found. 

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