Goitres Flashcards
what is a goitre?
an enlargement of the thyroid gland
diffuse and multinodular goitre are the processes
- disorders are most often due to the lack of dietary iodine and may be due to the lack of bioavailability of iodine
reduced T3/T4 production causes a rise in TSH - stimulating gland enlargement - may maintain a euthyroid state and if compensation fails a then have a goitrous hypothyroidism
what causes a diffuse goitre?
can be endemic - more than 10% population affected - normally an iodine deficiency &/or goitrogenic substances
sporadic - more common in females, puberty and young adults
- ingestion of substances limiting T3/T4 production
- Inborn errors of metabolism (dyshormonogenesis)
- Most cases – the cause is unknown
how do diffuse goitres present?
- Usually euthyroid – present with mass effects
- T3/T4 normal but TSH high or upper limit of normal
- In children dyshormonogenesis may cause cretinism
how does a mulit-nodular goitre develop?
Evolution from long standing simple goitre
variation of response of follicular cells to external stimuli - mutations of TSH signalling pathway
rupture of follicles, haemorrhage, scarring, calcification
may develop autonomous nodule - hyperthyroid
- 10% after 10 years
- low risk of malignancy (<5%)
how does a multi-nodular goitre evolve from a long-standing simple goitre?
o Recurrent hyperplasia and involution
o Enlargement can be impressive
o DDx thyroid neoplasm
what are the potential mass effects?
cosmetic
airway obstruction, dysphagia, compress vessels
what is non-thyroidal illness?
Also known as ‘sick euthyroid syndrome’
Commonly encountered in the unwell, hospitalised patient
Refers to the impact of intercurrent illness (e.g. severe infection) on the HPT axis
TSH typically suppressed initially then rises during recovery
Avoid checking TFTs in unwell patients unless clinical suspicion of thyroid disease
