Makindo Medical Notes

📖 Endemic goitre was historically common in Derbyshire (“Derbyshire neck”) until iodised salt was introduced in the 20th century. 💡 Pathophysiology: Iodine deficiency → ↓ thyroid hormone synthesis → ↑ TSH → thyroid hypertrophy and hyperplasia.

📖 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: “A thyroid gland whose lateral lobes each have a volume greater than the terminal phalanges of the patient’s thumbs.”
• Patients may be hypothyroid or euthyroid depending on compensation.

🌍 Geography

• UK: “Derbyshire neck” 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.

🧬 Aetiology / Pathophysiology

• Chronic iodine deficiency → reduced thyroxine (T4) and triiodothyronine (T3) production.
• Raised TSH stimulates thyroid hypertrophy and hyperplasia.
• Soil iodine deficiency due to flooding, glacial leaching, and geography → low iodine in locally grown food.
• Marine foods (seaweed, fish, shellfish) and iodised salt are rich sources of iodine.

🩺 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.

📊 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.

🔎 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.

⚕️ Management

• Public health: Iodised salt supplementation is the cornerstone worldwide.
• Neonatal screening: Detects congenital hypothyroidism early → prevents cretinism.
• Pregnancy: Adequate iodine intake is essential to avoid fetal brain damage.
• Thyroxine supplementation may be required in clinical hypothyroidism.

🌟 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.

📚 References

• WHO: Assessment of Iodine Deficiency Disorders