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๐ Endemic goitre was historically common in Derbyshire (โDerbyshire neckโ) until iodised salt was introduced in the 20th century.
๐ก Pathophysiology: Iodine deficiency โ โ thyroid hormone synthesis โ โ TSH โ thyroid hypertrophy and hyperplasia.
๐ About
- Iodine deficiency goitre is the most common cause of thyroid enlargement worldwide.
- Can cause cretinism in infants (severe intellectual disability, deaf-mutism, stunted growth).
- Goitre = enlarged thyroid. WHO definition: โA thyroid gland whose lateral lobes each have a volume greater than the terminal phalanges of the patientโs thumbs.โ
- Patients may be hypothyroid or euthyroid depending on compensation.
๐ Geography
- UK: โDerbyshire neckโ until 1930s, linked to iodine-poor soils.
- Endemic regions: Himalayan belt, Andes, sub-Saharan Africa, Southeast Asia, Western Pacific.
- Occurs when iodine intake < 10 mcg/day.
๐งฌ Aetiology / Pathophysiology
- Chronic iodine deficiency โ reduced thyroxine (T4) and triiodothyronine (T3) production.
- Raised TSH stimulates thyroid hypertrophy and hyperplasia.
- Soil iodine deficiency due to flooding, glacial leaching, and geography โ low iodine in locally grown food.
- Marine foods (seaweed, fish, shellfish) and iodised salt are rich sources of iodine.
๐ฉบ Clinical Features
- Painless neck mass or diffuse swelling.
- May cause compressive symptoms: stridor, dysphagia, neck discomfort.
- Often associated with hypothyroid symptoms (fatigue, cold intolerance) but can be euthyroid.
๐ WHO Grading of Goitre
- Grade 0: No palpable or visible goitre.
- Grade 1: Palpable but not visible with neck in normal position.
- Grade 2: Visible swelling consistent with thyroid enlargement.
๐ Investigations
- TFTs: May show hypothyroidism or subclinical hypothyroidism.
- Ultrasound: To assess thyroid size, nodules, echotexture.
- CT neck: Useful if retrosternal extension or compressive symptoms suspected.
โ๏ธ Management
- Public health: Iodised salt supplementation is the cornerstone worldwide.
- Neonatal screening: Detects congenital hypothyroidism early โ prevents cretinism.
- Pregnancy: Adequate iodine intake is essential to avoid fetal brain damage.
- Thyroxine supplementation may be required in clinical hypothyroidism.
๐ Summary:
Endemic goitre = iodine deficiency causing thyroid enlargement.
Historically common in Derbyshire (UK) and still a global health issue.
Preventable with iodised salt, critical in pregnancy to prevent cretinism.
๐ References