Thyroid storm

Also called thyrotoxic crisis, thyroid storm is a life-threatening hyperthyroid state characterised by multi-system involvement. It is the dangerous end of the spectrum of thyrotoxicosis.

Thyroid storm is rare (maybe 0.5 cases per 100,000 person-years)

Aetiology

The mechanism of thyroid storm is poorly understood but, as usual, several hypotheses have been proposed. The long and short of it is that there is too much of the thyroid hormones; interestingly enough there isn’t significantly more than in boring old hyperthyroidism.

In patients with underlying hyperthyroidism, particularly those with Graves’ disease, many factors may precipitate it.

• Abrupt discontinuation of antithyroid medicine.
• Thyroid (or non-thyroid) surgery.
• Acute iodine load (including amiodarone administration)
• Various acute illnesses.
• Burns.
• Stroke or traumatic brain injury.
• Parturition

Clinical manifestations

Thyroid storm is essentially just profound hyperthyroidism with multi-system (up) dysregulation and an acute precipitating event. In the case of no obvious precipitating event, Henry Burch and Leonard Wartofsky have developed a scoring system for the likelihood of the patients symptoms to represent a thyroid storm.¹

That article is only available in print at the authors alma mater, but the scale is succinct enough it needn’t be duplicated here. Thus, detailed below are the broad physiological manifestiations:

• Fever.
• Tachycardia, potentially leading to tachyarrythmia and heart failure.
• CNS involvement such as agitation, anxiety, restlessness, psychosis, or coma.
• Various gastrointestinal symptoms (simple nausea and vomiting to acute liver failure).
• The usual thyrotoxic suspects: tremor, goitre, hyperreflexia, hypertension, and exophthalmos.

Laboratory hyperthyroidism is usually also present but diagnosis and treatment can’t really wait for these results: the mortality rate of thyroid storm is greater than 10% in Japan.²

Management

The principles of management are to reverse the effects of the storm by suppressing the action of thyroid hormones, and also limiting the synthesis and activation of thyroid hormones.

Beta blockade

Thionamide

Lugol’s iodine

steroids

Further reading

Footnotes

1. Burch HB, Wartofsky L. Life-threatening thyrotoxicosis. Thyroid storm. Endocrinol Metab Clin North Am. 1993 Jun;22(2):263–77. ↩

2. Akamizu T, Satoh T, Isozaki O, Suzuki A, Wakino S, Iburi T, et al. Diagnostic criteria, clinical features, and incidence of thyroid storm based on nationwide surveys. Thyroid. 2012 Jul;22(7):661–79. ↩