Diagnosis and Treatment of Primary Hypothyroidism in Primary Care

Abstract

Decreased thyroid function occurs among 0,2–1% of men and 1,4–5% of women in the general population, and among people over 60 years among 2,5% of men and 6% of women. Hypothyroidism in 95% of cases is caused by thyroid disfunction (primary hypothyroidism), only 5% of cases are central hypothyroidism, associated with dysfunction of the pituitary gland (insufficient production of thyroid-stimulating hormone) and hypothalamus (impaired thyroliberin synthesis). Nonspecific clinical manifestations of hypothyroidism are the reason for examining the patient for thyroid hormone levels in primary care. Primary hypothyroidism screening is a common clinical situation in the general practitioner`s practice. According to Guideline 00514. Hypothyroidism of the Finnish Medical Research Society Duodecim Medical Publications Ltd, the use of which is approved by the Order of the Ministry of Health of Ukraine № 1422 of December 29, 2016, diagnosis of hypothyroidism and treatment of primary hypothyroidism are the tasks of primary care professionals. Decreased thyroid function may have subclinical and manifest forms, which are detected in the analysis of the results of thyroid hormones and clinical signs of the disease, require different treatment approaches. There are the differences in the use of levothyroxine replacement therapy in patients of different ages and depending on the causes of hypothyroidism. Patients under 55 years old are prescribed levothyroxine sodium in a daily dose of 1,6–1,8 μg/kg body weight. In patients over 55 years old, the daily requirement of levothyroxine sodium is calculated at 0,9 μg/kg body weight, taking into account existing cardiovascular disease. If patients are obese, the calculation is made on the «ideal» weight. The calculation of the dose and rules of levothyroxine sodium prescription in primary care are presented on the example of four clinical cases. The algorithm for control levothyroxine replacement therapy in patients with primary hypothyroidism is also presented.