Thyrotoxicosis causes

  • Commonest is Graves disease (auto Ab to TSH receptor with XS T4 and reduced TSH from pituitary)
  • Thyroid adenoma (or rarely carcinoma)
  • Toxic multi-nodular goitre
  • TRH producing pituitary adenoma
  • Iodine or amiodarone administration
  • 1% of thyrotoxic pushed by trigger (AMI, meds change, sepsis, surgery etc.) into thyroid storm (30 - 60yo)

Differential Dx

Thyroid storm

  • Life threatening hyper-metabolic state
  • Clinical Dx
  • Wt loss, tachyarrhythmias, alopecia, eye abnormalities etc
  • Hyper-metabolic state (pyrexia, hypertension, tachycardia [AF], tachypnoea, CCF, eye signs, hyperglycaemia)
  • Low TSH, high T3 T4
  • Look for precipitating cause (particularly sepsis)
  • Beware CCF (arrhythmia, persistent hypertension, cardiomyopathy)

General approach to Mx

  • Target each T4 synthesis step
  • Propylthiouracil (PTU) (inhibits hormone synthesis and T4 to T3 conversion)
  • Β blockers (traditionally propanolol but cardioselective may be safer in COPD/asthma etc) inhibit target organ effects and inhibit conversion T4 to T3
  • Iodine inhibits T4 release from gland: but must not be given before PTU as it may stimulate T4 release
  • Avoid Aspirin (unbinds T4 from plasma proteins)

Storm Management

Content by Dr Íomhar O' Sullivan. Last review Dr Simon Walsh, Dr David Herlihy, Dr ÍOS 4/11/21.