Hyperthyroidism

• Hyperthyroidism


  Over-production of the thyroid hormones, triiodothyronine (T3) and thyroxine (T4), by the thyroid gland
• Thyrotoxicosis


  Effects of an abnormal and excessive quantity of thyroid hormones in the body
• Primary hyperthyroidism


  Due to thyroid pathology, where the thyroid is behaving abnormally and producing excessive thyroid hormone
• Secondary hyperthyroidism


  Due to pathology in the hypothalamus or pituitary, where the pituitary gland produces too much thyroid-stimulating hormone, stimulating the thyroid gland to produce excessive thyroid hormones
• Subclinical hyperthyroidism


  Thyroid hormones (T3 and T4) are normal and thyroid-stimulating hormone (TSH) is suppressed (low), with absent or mild symptoms
• Graves’ disease


  An autoimmune condition where TSH receptor antibodies cause primary hyperthyroidism by stimulating TSH receptors on the thyroid, the most common cause of hyperthyroidism
• Toxic multinodular goitre


  Condition where nodules develop on the thyroid gland, unregulated by the thyroid axis, continuously producing excessive thyroid hormones, most common in patients over 50 years
• Exophthalmos


  Bulging of the eyes caused by Graves’ disease, where inflammation, swelling, and hypertrophy of the tissue behind the eyeballs force them forward, causing them to bulge out of the sockets
• Pretibial myxoedema


  Skin condition caused by deposits of glycosaminoglycans under the skin on the anterior aspect of the leg (the pre-tibial area), specific to Grave’s disease and a reaction to TSH receptor antibodies
• Pretibial myxoedema


  It gives the skin a discoloured, waxy, oedematous appearance over the pre-tibial area, specific to Grave’s disease and is a reaction to TSH receptor antibodies
• Goitre


  Refers to the neck lump caused by swelling of the thyroid gland
• Causes of hyperthyroidism


  • Graves’ disease
  • Inflammation (thyroiditis)
  • Solitary toxic thyroid nodule
  • Toxic multinodular goitre
• Thyroiditis


  Often causes an initial period of hyperthyroidism, followed by under-activity of the thyroid gland (hypothyroidism)
• Causes of thyroiditis


  • De Quervain’s thyroiditis
  • Hashimoto’s thyroiditis
  • Postpartum thyroiditis
  • Drug-induced thyroiditis
• Features universal to all causes of hyperthyroidism

  • Anxiety and irritability
  • Sweating and heat intolerance
  • Tachycardia
  • Weight loss
  • Fatigue
  • Insomnia
  • Frequent loose stools
  • Sexual dysfunction
  • Brisk reflexes on examination
• Graves’ disease features


  • Diffuse goitre (without nodules)
  • Graves’ eye disease, including exophthalmos
  • Pretibial myxoedema
  • Thyroid acropachy (hand swelling and finger clubbing)
  • Nodules may be palpable within a swollen thyroid gland (goitre) in patients with toxic multinodular goitre
• Solitary Toxic Thyroid Nodule

  • A single abnormal thyroid nodule acting alone to release excessive thyroid hormone, usually benign adenomas, treated with surgical removal
• De Quervain’s Thyroiditis


  • Also known as subacute thyroiditis, causing temporary inflammation of the thyroid gland, involving phases of thyrotoxicosis, hypothyroidism, and return to normal
• Thyrotoxic phase of De Quervain’s Thyroiditis


  Excessive thyroid hormones, thyroid swelling and tenderness, flu-like illness, raised inflammatory markers (CRP and ESR)
• Management of De Quervain’s Thyroiditis

  Supportive treatment involving NSAIDs for pain and inflammation, beta blockers for hyperthyroidism symptoms, levothyroxine for hypothyroidism symptoms, with a small number remaining hypothyroid long-term
• Thyroid Storm


  A rare and severe presentation of hyperthyroidism, also known as thyrotoxic crisis, treated similarly to thyrotoxicosis with additional supportive care
• Management of hyperthyroidism


  Guided by a specialist endocrinologist, involving first-line anti-thyroid drug Carbimazole taken for 12 to 18 months, with options for titration-block or block and replace, and second-line drug Propylthiouracil used similarly to Carbimazole
• MHRA warning in 2019 about the risk of acute pancreatitis in patients taking carbimazole
• Both carbimazole and propylthiouracil can cause agranulocytosis
• Propylthiouracil


  • Second-line anti-thyroid drug
  • Used similarly to carbimazole
  • Small risk of severe liver reactions, including death
  • Carbimazole is preferred due to lower risk
• Both carbimazole and propylthiouracil can cause agranulocytosis, with dangerously low white blood cell counts
• Agranulocytosis makes patients vulnerable to severe infections
• A sore throat is a key presenting feature of agranulocytosis
• If a patient on carbimazole or propylthiouracil presents with a sore throat, the cause is likely agranulocytosis
• Radioactive iodine treatment


  1. Involves drinking a single dose of radioactive iodine

  2. Thyroid gland takes up the iodine, emitted radiation destroys a proportion of thyroid cells

  3. Reduction in cell number leads to decreased thyroid hormone production

  4. Remission can take 6 months, often resulting in an underactive thyroid requiring long-term levothyroxine
• Rules for treatment with radioactive iodine

  • Women must not be pregnant or breastfeeding and must not get pregnant within 6 months of treatment
  • Men must not father children within 4 months of treatment
  • Limit contact with people after the dose, particularly children and pregnant women
• Beta blockers


  • Used to block adrenalin-related symptoms of hyperthyroidism
  • Propranolol is the usual choice, non-selectively blocking adrenergic activity
  • Control symptoms while definitive treatment takes effect
  • Particularly useful in patients with thyroid storm
• Surgery


  • Definitive option for hyperthyroidism
  • Removing whole thyroid gland (thyroidectomy) or toxic nodules stops excess thyroid hormone production
  • Patients will be hypothyroid after thyroidectomy, requiring lifelong levothyroxine