What are the key symptoms and signs that indicate a need for referral to an endocrinologist in a patient with hypothyroidism?

Key symptoms and signs indicating a need for referral to an endocrinologist in a patient with hypothyroidism include:

• Suspected secondary hypothyroidism (central hypothyroidism) requiring specialist assessment of the underlying cause ¹.
• Suspected subacute thyroiditis ¹.
• Presence of a goitre, thyroid nodule, or structural changes in the thyroid gland, especially if malignancy is suspected, which requires referral via a suspected cancer pathway ¹.
• Suspected associated endocrine diseases such as Addison's disease, where thyroid hormone replacement should not be started before specialist glucocorticoid replacement ¹.
• Atypical or difficult to interpret thyroid function tests (TFTs), for example, low TSH with low free thyroxine (FT4), which may indicate pituitary adenoma or thyroid hormone resistance ¹.
• Suspected underlying causes of hypothyroidism such as drug-induced hypothyroidism (e.g., amiodarone or lithium) ¹.
• Female patients planning pregnancy, as specialist input is recommended for management ¹.
• Persistent symptoms despite treatment that may require specialist assessment for dose adjustment or alternative diagnoses ¹.