Endocrine Abstracts

Isolated hypothyroxinemia is rarely and briefly mentioned in medical textbooks and seldom discussed at endocrine conferences. It is most often, but not exclusively encountered in pregnancy. The author presents cases of isolated hypothyroxinemia encountered at a private endocrine practice in Budapest, Hungary and a specialized medical practice in Berlin, Germany. In the last seven years the author encountered about thirty cases: app. 60% in women who were 17-85 years old and app. 40% in men who were 50-86 years old. Women with isolated hypothyroxinemia in fertile age had a long history of infertility, miscarriage, primary and/or secondary amenorrhea and psychiatric symptoms. Most of these patients responded well to thyroxin supplementation and their symptoms improved or disappeared. The majority of patients over 60 years of age did not show any symptoms. They were predominantly closely followed and received thyroxin supplementation only in a few cases. In summary, isolated hypothyroxinemia seems to be a rare entity which is easily dismissed. In women of fertile age isolated hypothyroxinemia should receive more attention. An fT4-value below the reference range should not be regarded automatically as laboratory error even if the TSH is adequate.