Hyperthyroidism

Hyperthyroidism is when the thyroid gland makes too much thyroid hormone. It speeds up many body systems and, if untreated, can cause heart rhythm problems, osteoporosis, and — in rare severe cases — thyroid storm. It is less common than hypothyroidism but important to recognise.

Common symptoms

• Unexplained weight loss despite good appetite.
• Fast or irregular heartbeat, palpitations.
• Heat intolerance, excessive sweating.
• Tremor of hands, anxiety, irritability, insomnia.
• Frequent loose stools.
• Scanty or missed periods.
• Muscle weakness (climbing stairs, getting up from floor).
• Eye signs (staring, lid lag, protrusion) — classical of Graves' disease.

Common causes

• Graves' disease — autoimmune; the commonest cause.
• Toxic nodule or multinodular goitre — common in older adults, especially in historically iodine-deficient regions.
• Thyroiditis (including post-partum) — transient; often settles on its own.
• Too much levothyroxine in someone being treated for hypothyroidism.
• Excess iodine exposure — iodine-containing cough syrups, some contrast scans, sea-plant supplements (kelp).

Diagnosis

• TSH low, Free T4 and/or Free T3 high.
• Thyroid antibodies (TRAb, anti-TPO) to identify Graves'.
• Radioiodine uptake and scan, or thyroid ultrasound to tell Graves' from toxic nodule / thyroiditis — decides treatment.

Treatment

• Anti-thyroid tablets (carbimazole class, propylthiouracil in first-trimester pregnancy) — control symptoms, often used for 12–18 months in Graves'.
• Beta-blocker class for palpitations, tremor, anxiety while the anti-thyroid works.
• Radioactive iodine (RAI) — simple outpatient treatment, often permanent cure.
• Surgery (thyroidectomy) — for large goitre, pregnancy plans, or Graves' eye disease.
• Thyroid storm (very high fever, fast heart, confusion) — medical emergency, dial 112.

During pregnancy

• Uncontrolled hyperthyroidism can cause miscarriage, preterm birth, and heart failure — safe treatment is available under an endocrinologist + obstetrician team.
• Avoid radioactive iodine in pregnancy and breastfeeding.