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Hyperthyroidism and thyrotoxicosis C013

Last amended 
17 January 2022
Current RMA Instruments
Reasonable Hypothesis SOP
5 of 2022
Balance of Probabilities SOP
6 of 2022
Changes from previous Instruments

SOP Bulletin 228

ICD Coding
  • ICD-10-AM Codes:  E05.3, E05.8, E05.9
Brief description

This is a pathology where there is an elevated level of thyroid hormone in the blood, with symptoms or signs of thyroid hyperfunction.  If the elevation in thyroid hormone is due to excessive secretion by the thyroid gland, then it is called hyperthyroidism.  The term thyrotoxicosis covers the clinical manifestations of excess thyroid hormone from any cause (including from outside the thyroid gland).  Several of the most common causes of hyperthyroidism/thyrotoxicosis are not covered by this SOP.  Graves disease, toxic thyroid adenoma and toxic multinodular goitre account for the large majority of cases of hyperthyroidism/thyrotoxicosis but are covered by other SOPs and not this SOP.  Graves disease has its own SOP.  Toxic adenoma and toxic goitre are covered by the goitre SOP.

Confirming the diagnosis

The diagnosis is made from blood tests showing levels of thyroid hormones (TSH, T3 and T4).  An additional finding of thyroid stimulating autoantibody usually indicates Graves disease, which is covered by a separate SOP.  Additional testing, such as ultrasound scanning or radionuclide imaging may be undertaken to further identify the pathology.

The appropriate specialist is an endocrinologist.

Additional diagnoses covered by SOP
  • Thyrotoxic crisis (where not due to Graves disease or another excluded condition)
Conditions excluded from SOP
  • Hashimoto thyroiditis*
  • Graves disease*
  • Subclinical hyperthyroidism (N.I.F.)
  • Sick euthyroid syndrome#
  • Gestational transient thyrotoxicosis#
  • Euthyroid hyperthyroxinaemia#
  • Toxic multinodular goitre* - goitre SOP
  • Toxic uninodular goitre* - goitre SOP
  • Toxic thyroid adenoma* goitre SOP

* Another SOP applies

# Non-SOP condition

Clinical onset

The clinical presentation and the extent of symptoms is variable.  Classic symptoms are non-specific and include heat intolerance, tremor, palpitations, anxiety, weight loss despite a normal or increased appetite, increased frequency of bowel movements, and shortness of breath.

Clinical worsening

The condition is usually responsive to appropriate treatment and able to be well controlled.  Various treatment approaches may be used depending on the underlying cause. Worsening that is ongoing is unlikely.