Enlarged palpable thyroid gland, which moves on swallowing
Aetiology May be a benign disorder but is also associated with several thyroid diseases, including iodine deficiency, Hashimoto’s thyroiditis, and some of the causes of hyperthyroidism Pathophysiology Reduced T3/T3 production causes a rise in TSH, stimulating gland enlargement This may maintain euthyroid state or if compensation fails there will be goitrous hypothyroidism Diffuse goitre Aetiology Physiological goiter - puberty, pregnancy Autoimmune thyroid disease - Hasimoto's thyroiditis, Grave's disease thyrotoxicosis Endemic Inflammation - acute (de Quervain's) thyroiditis Sporadic 4:1 females, usually during puberty/YA Most cases have no clear cause Some associated with ingestion of substances limiting T3/T4 production or inborn errors of metabolism (dyshormonogenesis) Clinical presentation Entire thyroid gland swells and is smooth to the touch Usually euthyroid, if not may be symptoms of hyper/hypothyroidism Present with mass effects Cosmetic Compression of the trachea → exertional dyspnoea and, in severe cases, stridor or wheezing Compression of the oesophagus → dysphagia In children dyshormonogenesis may cause cretinism Investigations Thyroid function tests - T3/T4 normal, TSH high or upper limit of normal Management Treat underlying cause if appropriate (iodine deficiency, autoimmune thyroid disease) Usually no further treatment needed (unless causing obstructive symptoms - surgery) Multi-nodular goitre Aetiology Develops from a long-standing simple sporadic goitre Pathophysiology Variation of response of follicular cells to external stimuli - recurrent hyperplasia and involution Mutations of TSH signalling pathway There will be a varying degree of fibrosis, haemorrhage and calcification Clinical presentation Irregular enlarged thyroid due to nodule formation - thyroid feels bumpy on palpation Enlargement can be impressive Presents with mass effects Can be inactive or toxic Toxic multinodular goitres are responsible for ~35% of cases of hyperthyroidism Toxic nodules have an increased risk of malignant transformation Investigations Thyroid function tests - TSH usually normal or slightly suppressed, fT3/T4 normal if inactive or increased if toxic US scan - sensitive method for delineating nodules and can demonstrate whether they are cystic or solid FNA - to assess cancer risk for prominent palpable and suspicious nodules CT scan - may detect retrosternal extension and tracheal compression in patients with a very large goitre or clinical symptoms Thyroid isotope scan - toxic or non-toxic Flow volume loops if considering other potential causes of breathlessness Management Antithyroid drugs if toxic Radioactive iodine if significant hyperthyroid Surgery if structural problem or significant retrosternal extension
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