Endocrine System >
Hyperthyroidism

“The clinical effect of excess thyroid hormone, usually from gland hyperfunction”

Aetiology & Pathogenesis
  • Graves’ Disease (2/3 cases of Hyperthyroidism):
    • IgG autoantibody binds Thyrotropin Receptors -> Smooth thyroid enlargement + Increased thyroid hormone production + React with orbital autoantigens
  • Toxic Multinodular Goitre:
    • Elderly + in iodine-deficient areas
    • Nodules which secrete thyroid hormones
  • Toxic Adenoma:
    • Solitary nodule producing T3 + T4
  • Ectopic Thyroid Tissue:
    • Metastatic follicular thyroid cancer
    • Struma Ovarii (Ovarian teratoma with thyroid tissue)
  • Exogenous:
    • Iodine excess e.g. food contamination, contrast media
  • Others
Clinical Presentation
  • Symptoms:
    • Heat intolerance
    • Diarrhoea
    • Weight loss
    • Increased appetite (may cause paradoxical weight gain)
    • Overactive
    • Palpitations
    • Sweat
    • Tremor
    • Irritability
    • Labile emotions
    • Oligomenorrhoea +/- Infertility
  • Signs:
    • Fast / Irregular Pulse (AF or SVT)
    • Warm moist skin
    • Fine tremor
    • Palmar Erythema
    • Thin hair
    • Lid lag & Lid retraction
  • Signs of Graves Disease:
    • Thyroid Eye Disease
    • Pretibial Myxoedema
    • Thyroid Acropachy
Investigations
  • Bloods:
    • Low TSH
    • Low T4
    • High T3
    • May be mild normocytic anaemia
    • Mild neutropenia (in Graves)
    • Elevated ESR
    • Ca2+
    • LFTs
    • Thyroid Autoantibodies
  • Imaging: n/a
  • Special:
    • Isotope Scan – If the cause is unclear, to detect nodular disease or subacute thyroiditis
    • Visual Fields, Acuity + Eye Movements – If ophthalmopathy present
Management
  • Conservative:
  • Medical:
    • Medication
      • Beta-Blockers e.g. Propanolol 40mg/6h
      • Antithyroids e.g. Carbimazole
    • Radioiodine Treatment
  • Surgical:
    • Thyroidectomy
      • Risk of recurrent laryngeal nerve damage and hypoparathyroidism
      • Patients become hypothyroid post-surgery, so thyroid replacement needed
Complications
  • Thyroid Storm
  • Heart Failure (Thyrotoxic Cardiomyopathy)
  • Angina
  • Atrial Fibrillation
  • Osteoporosis
  • Ophthalmopathy
  • Gynaecomastia

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