Secondary hypothyroidism in adults: diagnosis and treatment

Abstract

Secondary hypothyroidism is a rare disease. There is a number of questions and difficulties in diagnosis and management of this condition. There are two forms of secondary hypothyroidism: congenital (casuistic seldom) and acquired. The main causes of secondary hypothyroidism in adults are tumors of the hypothalamic-pituitary region and the state after surgical and radiation effects on this area. Hormonally active and inactive pituitary macroadenomas cause the development of acquired secondary hypothyroidism in more than 50% of cases. The development of secondary hypothyroidism is possible years after the radiotherapy of brain tumors. As well as in case of primary hypothyroidism, the clinical manifestations of secondary hypothyroidism are non-specific. Diagnosis and management of this pathology is often complicated by its combination with the deficiency of other tropic hormones. The diagnosis of secondary hypothyroidism is based on anamnestic data and laboratory tests - the simultaneous determination of the levels of fT4 and TSH. The level of fT4 today is also used as the main marker of the adequacy of the dose of L-T4 in the treatment of secondary hypothyroidism. The results of recent studies help us to optimize replacement therapy in secondary hypothyroidism. However, the use of additional biochemical markers to assess the adequacy of replacement therapy remains unexplored.