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Hyperthyroid Crisis (Thyrotoxic Storm)

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PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

See also: Thyroid Function Tests written for patients

Synonyms: thyrotoxic crisis, thyroid storm, hyperthyroid storm

Hyperthyroid crisis is an uncommon medical emergency caused by an exacerbation of hyperthyroidism characterised by decompensation of one or more organ systems in people with untreated or poorly treated hyperthyroidism.[1] Hyperthyroid crisis usually occurs in patients already known to have hyperthyroidism but may be the first presentation of hyperthyroidism.[2]

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.

Hyperthyroid crisis is rare: approximately 1-2% of patients with hyperthyroidism progress to a hyperthyroid crisis.[3]

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Hyperthyroid crisis classically occurs in patients with underlying Graves' disease or toxic multinodular goitre.[3] Often, there is sudden onset of severe hyperthyroidism with:[4][5]

  • 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, psychosis, seizures or coma.

Hyperthyroid crisis is most often seen in a thyrotoxic patient with intercurrent illness, trauma or emergency surgery. Common precipitants include:[3]

  • 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.
  • Treatment of the precipitating cause - eg, any suspected infection.
  • 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.
  • Antithyroid treatment:
    • Carbimazole or propylthiouracil orally. After four hours, give Lugol's solution (aqueous iodine oral solution).
    • 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.
    • Corticosteroids - block T4 to T3 conversion.
  • For severe agitation, sedate with chlorpromazine.
  • Keep cool with tepid sponging and with paracetamol. Avoid aspirin which can increase T4.
  • Treat heart failure:
    • High-dose digoxin may be needed.
    • Cardioversion will not be effective for atrial fibrillation until the patient is euthyroid.
    • Give furosemide or bumetanide as required, depending on the degree of pulmonary oedema and of dehydration.
  • Anticoagulation: prophylactic subcutaneous heparin to prevent thromboembolism; IV infusion if in atrial fibrillation.
  • If the patient fails to improve within 1-2 days, it may be necessary to consider exchange transfusion, peritoneal dialysis or haemodialysis. Plasma exchange has been used successfully in hyperthyroid crisis due to excess thyroid hormone tablets, and in conditions in which oral or conventional therapy is not possible.[3]
  • Further thyroid management will depend on the progress of each individual patient and must be under the care of an endocrinologist.
  • Untreated hyperthyroid crisis is usually fatal.[7]
  • Even with treatment, a recent study in Japan found a mortality rate of 11%. Multiple organ failure was the most common cause of death, followed by heart failure, respiratory failure, arrhythmia, disseminated intravascular coagulation, gastrointestinal perforation, hypoxic brain syndrome and septicaemia.[8]

Identification and prevention or early treatment of precipitating factors.

Further reading & references

  1. Migneco A, Ojetti V, Testa A, et al; Management of thyrotoxic crisis. Eur Rev Med Pharmacol Sci. 2005 Jan-Feb;9(1):69-74.
  2. Martinez-Diaz GJ, Formaker C, Hsia R; Atrial fibrillation from thyroid storm. J Emerg Med. 2012 Jan;42(1):e7-9. doi: 10.1016/j.jemermed.2008.06.023. Epub 2008 Dec 20.
  3. Schraga ED; Hyperthyroidism, Thyroid Storm, and Graves Disease in Emergency Medicine, Medscape, Mar 2012
  4. Cooper DS; Hyperthyroidism. Lancet. 2003 Aug 9;362(9382):459-68.
  5. Reid JR, Wheeler SF; Hyperthyroidism: diagnosis and treatment. Am Fam Physician. 2005 Aug 15;72(4):623-30.
  6. Rashid M, Rashid MH; Obstetric management of thyroid disease. Obstet Gynecol Surv. 2007 Oct;62(10):680-8; quiz 691.
  7. Czako PF et al; Thyrotoxic Storm Following Thyroidectomy, Medscape, Nov 2012
  8. Akamizu T, Satoh T, Isozaki O, et al; Diagnostic criteria, clinical features, and incidence of thyroid storm based on nationwide surveys. Thyroid. 2012 Jul;22(7):661-79. doi: 10.1089/thy.2011.0334. Epub 2012 Jun 12.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Colin Tidy
Current Version:
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
2292 (v23)
Last Checked:
Next Review:
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