Strategies for improved management of hypothyroidism
Management is clear-cut—yet many patients don’t reach treatment goals. To optimize quality of life, master the fine points of T4 replacement and address the impact of comorbidities.
PRACTICE RECOMMENDATIONS
› Prescribe levothyroxine (LT4) to maintain thyroid-stimulating hormone (TSH) at 4 to 7 mIU/L in select patients with primary hypothyroidism for whom that range of the serum TSH level can be considered appropriate (ie, those older than 65 years and those who have underlying coronary artery disease or another debilitating chronic disorder). A
› Counsel all women of childbearing age with primary hypothyroidism that they need to have their dosage of LT4 increased as soon as pregnancy is suspected. A
› Keep in mind that treating hypothyroidism is not always necessary in older patients who have subclinical disease and a serum TSH level < 10 mIU/L. A
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
When to seek consultation
A patient with hypothyroidism should be referred to Endocrinology if they are < 18 years of age, pregnant, unresponsive to therapy, or have cardiac disease, coexisting endocrine disease, suspected myxedema coma, goiter or thyroid nodules, or a structural thyroid abnormality.
What we know about nutrition and hypothyroidism
Although it is commonly recognized that iodine is essential for production of thyroid hormone, other nutritional factors might contribute to proper production of thyroid hormones, including:
- adequate intake of iron, tyrosine, selenium, zinc, and vitamins E, B2, B3, B6, C, and D44,45
- selenium and zinc, which increase conversion of T4 to T3 and might be important in the management of hypothyroid patients40,46
- vitamin A, zinc, and regular exercise, which have been shown to improve cellular sensitivity to thyroid hormones.
Low iron stores can contribute to persistent symptoms and poor quality of life in patients with hypothyroidism, despite their being treated according to guidelines.29,47
Despite what is known about these nutritional connections, there is insufficient evidence that improving nutrition can reverse hypothyroidism.
Prevention
Prevention of hypothyroidism should take into account variables that affect or inhibit thyroid function, such as stress, infection (eg, Epstein-Barr virus), excessive fluoride intake, toxins (eg, pesticides, solvents, mercury, cadmium, and lead), autoimmune disease (eg, celiac disease), and food sensitivity.54,55 Oxidative stress can also cause thyroid impairment.40-48,54-58
Otherwise, there are, at present, no effective strategies for preventing thyroid disorders.
Subclinical hypothyroidism: Elusive management target
Subclinical hypothyroidism is defined as a normal serum FT4 level in the presence of an elevated serum TSH level. The prevalence of subclinical hypothyroidism varies from 3% to 15%, depending on the population studied; a higher incidence has been noted in women and older people.59 In the NHANES III,1 which excluded people with previously diagnosed thyroid disease, the incidence of subclinical hypothyroidism was 4.3%.
Continue to: Causes of subclinical...
