ABSTRACT
The diagnosis of primary hypothyroidism is based on clinical features supported by biochemical evidence of elevated serum thyroid-stimulating hormone (TSH), and low or normal free thyroxine. Non-specific symptoms such as lethargy, ‘brain fog’ and difficulty with weight management occur in up to 5%–10% of people treated for hypothyroidism with a serum TSH within the reference range. Serum triiodothyronine levels can remain within the reference range even in severe hypothyroidism. Younger persons with cardiovascular risk factors should also be treated, since studies have shown an association between subclinical hypothyroidism and cardiovascular mortality. CRP or ESR is elevated in cases of viral thyroiditis. Hyperthyroidism commonly results from Graves’ disease, toxic multinodular goitre or toxic nodule. Drug causes include amiodarone, lithium and ingestion of products containing high iodine loads. Antithyroid treatment with carbimazole or propylthiouracil can be initiated in primary care after discussion with the endocrine team, pending hospital appointment.
