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Hyperthyroid crisis

Thyrotoxic storm

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Overactive thyroid gland article more useful, or one of our other health articles.

Synonyms: thyrotoxic crisis, thyroid storm, hyperthyroid storm

Hyperthyroid crisis, or thyrotoxic storm, is an extreme manifestation of thyrotoxicosis due to overproduction of thyroid hormones.

Although hyperthyroid crisis usually occurs in patients already known to have hyperthyroidism, it may be the first presentation of hyperthyroidism.

Early recognition and aggressive treatment are essential. Hyperthyroid crisis can occur in patients with a toxic adenoma or multinodular toxic goitre but is more often seen in patients with Graves' disease.

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Hyperthyroid crisis is rare. It has an incidence of 0.2 cases per 100,000 population and approximately 1-2% of patients with hyperthyroidism progress to a hyperthyroid crisis1.


The diagnosis of hyperthyroid crisis is clinical - a combination of patient presentation and laboratory values confirming hyperthyroidism2. The presentation of hyperthyroid crisis can be varied and, therefore, difficult to diagnose, especially in a trauma patient who is likely to be tachycardic and may also have altered mental status3.

Hyperthyroid crisis classically occurs in patients with underlying Graves' disease or toxic multinodular goitre. Often, there is sudden onset of severe hyperthyroidism with4:

  • Hyperpyrexia (over 41°C), dehydration.

  • Heart rate greater than 140 beats per minute (with or without atrial fibrillation or other arrhythmias), hypotension, atrial dysrhythmias, congestive heart failure.

  • Nausea, jaundice, vomiting, diarrhoea, abdominal pain.

  • Confusion, agitation, delirium, psychosis5, seizures or coma.

Cocaine intoxication and hyperthyroid crisis lead to clinical pictures with overlapping signs, including hyperpyrexia, tachycardia, and central nervous system disturbances2.

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Hyperthyroid crisis is most often seen in a thyrotoxic patient with intercurrent illness, trauma or emergency surgery.

Common precipitants include6:


  • Investigations for any underlying precipitant - eg, infection screen.

  • TFTs: elevated T3 and T4 levels, elevated T3 uptake, suppressed TSH levels.

  • Indications of decompensation of homeostasis - eg, renal dysfunction, elevated creatine kinase, electrolyte imbalance (due to dehydration), anaemia, thrombocytopenia, raised white cell count, abnormal LFTs (raised levels of transaminases, lactate dehydrogenase, alkaline phosphatase and bilirubin), hypercalcaemia, hyperglycaemia.

  • ECG.

  • CXR.

  • Arterial blood gases and pH.

NB: the degree to which the thyroid hormone levels are elevated does not determine the presence or absence of hyperthyroid crisis2.

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Once a thyroid crisis is suspected, emergency treatment should be initiated even before the arrival of TFTs.

There are four components to the therapy of thyroid storm7:

  • Treatment directed at thyroid hormone synthesis and secretion by the thyroid gland.

    • Antithyroid treatment:

      • Carbimazole or propylthiouracil orally. However, anti-thyroidal therapy is sometimes limited due to rare and serious side-effects or failure to control disease progression8.

      • After four hours, give Lugol's solution (aqueous iodine oral solution). Iodine should typically be administered after thionamide therapy has been started to prevent stimulation of new hormone synthesis2.

      • Beta-blockers (initially IV propranolol 5 mg, then orally) unless contra-indicated (eg, asthma - but heart failure is not a contra-indication). Diltiazem can be used if propranolol is contra-indicated.

      • Hydrocortisone administration is also recommended. It treats possible relative adrenal insufficiency while also decreasing T4 to T3 conversion9.

      • Patients who fail medical therapy should be treated with therapeutic plasma exchange or thyroidectomy810.

  • Addressing the distribution, content, and action of the thyroid hormones already in the peripheral circulation.

  • Determining the precipitating cause of storm when possible eg infection, and ensuring that there is no ongoing contribution to the exacerbation of the thyrotoxicosis.

  • Supportive and symptomatic therapy for the systemic decompensation present.

    • Resuscitation: oxygen, intravenous (IV) access and give 0.9% saline infusion (adjust IV fluids as necessary, ideally guided by central venous pressure) and nasogastric tube if there is vomiting.

    • For severe agitation, sedate with chlorpromazine.

    • Keep cool with tepid sponging and with paracetamol. Avoid aspirin which can increase T4 levels1.

Addressing all four components of treatment provides the best opportunity to avoid a fatal outcome. Further thyroid management will depend on the progress of each individual patient and must be under the care of an endocrinologist.

Patients who fail medical therapy should be treated with therapeutic plasma exchange or thyroidectomy48. Thyroidectomy has been attempted with mixed results for the rare patient who does not respond to medical treatment, who continues to have elevated thyroid function tests and/or symptoms7.


  • Untreated hyperthyroid crisis is usually fatal due to hyperthermia, cardiac arrhythmias, multi-organ failure11, and sepsis6.

  • Even with early diagnosis and targeted treatment, the mortality rate of hyperthyroid crisis ranges from 10-30%4.

  • It has a fatality rate of 50-90% if left untreated12.


Identification and prevention or early treatment of precipitating factors.

Further reading and references

  • Snyder S, Joseph M; The Perfect Storm: A Case of Ischemic Stroke in the Setting of Thyroid Storm. Cureus. 2020 May 6;12(5):e7992. doi: 10.7759/cureus.7992.
  1. Parasa M, Chinthakunta BK, Vemuri NN, et al; Out of the blue! Thyroid crisis. Anesth Essays Res. 2015 Jan-Apr;9(1):130-2. doi: 10.4103/0259-1162.150179.
  2. Lacy ME, Utzschneider KM; Cocaine Intoxication and Thyroid Storm: Similarity in Presentation and Implications for Treatment. J Investig Med High Impact Case Rep. 2014 Oct 13;2(4):2324709614554836. doi: 10.1177/2324709614554836. eCollection 2014 Oct-Dec.
  3. Prosser JS, Quan DK; Trauma triggering thyrotoxic crisis with lactic acidosis. J Emerg Trauma Shock. 2015 Oct-Dec;8(4):232-234.
  4. Chiha M, Samarasinghe S, Kabaker AS; Thyroid storm: an updated review. J Intensive Care Med. 2015 Mar;30(3):131-40. doi: 10.1177/0885066613498053. Epub 2013 Aug 5.
  5. Desai D, Zahedpour Anaraki S, Reddy N, et al; Thyroid Storm Presenting as Psychosis. J Investig Med High Impact Case Rep. 2018 May 18;6:2324709618777014. doi: 10.1177/2324709618777014. eCollection 2018 Jan-Dec.
  6. Hyperthyroidism; NICE CKS, February 2020 (UK access only)
  7. Ylli D, Klubo-Gwiezdzinska J, Wartofsky L; Thyroid emergencies. Pol Arch Intern Med. 2019 Aug 29;129(7-8):526-534. doi: 10.20452/pamw.14876. Epub 2019 Jun 25.
  8. Carhill A, Gutierrez A, Lakhia R, et al; Surviving the storm: two cases of thyroid storm successfully treated with plasmapheresis. BMJ Case Rep. 2012 Oct 19;2012. pii: bcr2012006696. doi: 10.1136/bcr-2012-006696.
  9. Bahn RS, Burch HB, Cooper DS, et al; Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocr Pract. 2011 May-Jun;17(3):456-520.
  10. Koh H, Kaushik M, Loh JK, et al; Plasma exchange and early thyroidectomy in thyroid storm requiring extracorporeal membrane oxygenation Endocrinol Diabetes Metab Case Rep. 2019 Jul 26;2019(1):1-6. doi: 10.1530/EDM-19-0051.
  11. Nai Q, Ansari M, Pak S, et al; Cardiorespiratory Failure in Thyroid Storm: Case Report and Literature Review. J Clin Med Res. 2018 Apr;10(4):351-357. doi: 10.14740/jocmr3106w. Epub 2018 Feb 18.
  12. Nakashima Y, Kenzaka T, Okayama M, et al; A case of thyroid storm with cardiac arrest. Int Med Case Rep J. 2014 May 8;7:89-92. doi: 10.2147/IMCRJ.S63475. eCollection 2014.

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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