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# Thyroid storm

Thyroid storm is a rare, life-threatening flare of an overactive thyroid, with high fever, a racing heart and confusion. It is a medical emergency.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Thyroid gland](https://durgical.com/en/anatomy/thyroid-gland/)
- [Pituitary gland](https://durgical.com/en/anatomy/pituitary-gland/)
- [Parathyroid glands](https://durgical.com/en/anatomy/parathyroid-glands/)

## In the clinical exam

- [Hyperthyroidism and hypothyroidism: the signs](https://durgical.com/en/clinical-exam/hyperthyroidism-and-hypothyroidism-the-signs/)

## Why it happens

- [Actions of thyroid hormones](https://durgical.com/en/physiology/actions-of-thyroid-hormones/)
- [Body temperature regulation](https://durgical.com/en/physiology/body-temperature-regulation/)
- [Thyroid hormone synthesis](https://durgical.com/en/biochemistry/pathways/thyroid-hormone-synthesis/)
- [Thyroid follicles, C cells and parathyroid](https://durgical.com/en/histology/thyroid-follicles-c-cells-and-parathyroid/)

## What it is

An extreme, decompensated form of thyrotoxicosis in which excess thyroid hormone causes fever, cardiovascular failure and altered mental status. It is a clinical diagnosis and an endocrine emergency.

## Who gets it

Uncommon, occurring in a small fraction of people admitted with thyrotoxicosis, but with a high death rate. Most cases arise in untreated or poorly controlled Graves disease, which is the commonest cause of hyperthyroidism in Colombia and Latin America.

## Causes

- Underlying Graves disease most often; less often toxic multinodular goitre or toxic adenoma
- Trigger: infection, surgery or trauma, childbirth, diabetic ketoacidosis
- Stopping antithyroid drugs abruptly
- Iodine load (iodinated contrast, amiodarone) or radioiodine therapy
- Thyroid surgery in a patient who was not made euthyroid first

## Risk factors

- Untreated or poorly controlled hyperthyroidism
- Poor adherence to antithyroid treatment
- Acute illness or emergency surgery
- Pregnancy and the peripartum period

## Pathophysiology

A sudden stressor on top of thyrotoxicosis increases free hormone and the sensitivity of tissues to catecholamines. Metabolic rate and heat production soar, the heart is driven to tachycardia and high-output failure, and the brain is affected. The scale of the response, not the absolute hormone level, defines the storm.

## Classification

- Scored with the Burch-Wartofsky point scale (temperature, CNS, GI-hepatic, heart rate, heart failure, atrial fibrillation, precipitant)
- Japan Thyroid Association criteria as an alternative

## Symptoms and signs

- High fever and profuse sweating
- Marked tachycardia, often atrial fibrillation
- Agitation, delirium, psychosis, seizures or coma
- Nausea, vomiting, diarrhoea, abdominal pain and jaundice
- Goitre, tremor and eye signs of Graves disease

## Red flags

- Altered consciousness
- Signs of heart failure or shock
- Jaundice, a sign of hepatic dysfunction linked to poor outcome
- Temperature above 40 °C

## Diagnosis

**Clinical**
Diagnosed on clinical grounds in a patient with thyrotoxicosis plus multi-organ decompensation, supported by a high Burch-Wartofsky score. Treatment starts without waiting for laboratory confirmation.

**Tests**
Suppressed TSH with high free T4 and/or T3 (levels do not separate storm from uncomplicated thyrotoxicosis). Search for triggers: blood count, cultures, glucose, electrolytes, [liver](https://durgical.com/en/anatomy/liver/) tests, ECG; TSH receptor antibodies support Graves disease.

**Imaging**
[Chest](https://durgical.com/en/anatomy/region/chest/) X-ray and echocardiography to assess infection and cardiac function; thyroid ultrasound later to study the gland.

## Differential diagnosis

- Sepsis
- Phaeochromocytoma crisis
- Malignant hyperthermia or neuroleptic malignant syndrome
- Sympathomimetic poisoning (cocaine, amphetamines)
- Heat stroke

## Goal of treatment

Reduce new hormone synthesis and release, block peripheral effects, support organs in intensive care, and treat the trigger.

## Treatment

**Acute**
Beta-blockers (propranolol is the classic choice) to control heart rate and adrenergic symptoms, with caution in heart failure.

**Medical**
Thionamides (propylthiouracil or methimazole) to block synthesis; iodine solution given at least an hour after the thionamide to block release; glucocorticoids to reduce T4-to-T3 conversion and cover relative adrenal insufficiency.

**Acute**
Supportive care in intensive care: fluids, active cooling and paracetamol (avoiding aspirin, which frees bound hormone), oxygen, and treatment of infection or other trigger.

**Follow-up**
Continuous cardiac monitoring, temperature, fluid balance, glucose and mental status; nursing focus on cooling, arrhythmia detection and a calm, safe environment.

**Surgical**
Definitive treatment after recovery: radioactive iodine or thyroidectomy; urgent surgery or plasma exchange if medical therapy fails.

## Complications

- High-output heart failure and cardiogenic shock
- Atrial fibrillation with thromboembolism
- Acute liver failure
- Multi-organ failure and death

## Prognosis

Mortality remains significant even with intensive care, mainly from heart failure and multi-organ failure. Early recognition and treatment improve survival; afterwards the hyperthyroidism needs definitive treatment.

## Prevention

- Making patients euthyroid before planned surgery or radioiodine
- Adherence to antithyroid drugs and prompt treatment of infections in hyperthyroid patients

## Test yourself

Think of the answer, then tap the question to see it.

## Is thyroid storm diagnosed by hormone levels or clinically?

Clinically: thyrotoxicosis with fever, tachycardia, CNS and GI dysfunction; hormone levels do not separate it from simple thyrotoxicosis.

## Why is iodine given only after a thionamide in thyroid storm?

Given first, iodine could serve as substrate for more hormone synthesis; the thionamide blocks synthesis before iodine blocks release.

## Which antipyretic is avoided in thyroid storm and why?

Aspirin, because it displaces thyroid hormone from binding proteins and raises free hormone.

## Which drug class controls the adrenergic symptoms of thyroid storm?

Beta-blockers, classically propranolol, which also reduces peripheral T4-to-T3 conversion.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/thyroid-storm/)

## Related conditions

- [Graves disease (hyperthyroidism)](https://durgical.com/en/conditions/graves-disease/)
- [Thyroid nodule](https://durgical.com/en/conditions/thyroid-nodule/)
- [Atrial fibrillation](https://durgical.com/en/conditions/atrial-fibrillation/)
- [Heart failure](https://durgical.com/en/conditions/heart-failure/)
- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)
- [Myxoedema coma](https://durgical.com/en/conditions/myxoedema-coma/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Thyroid storm](https://medlineplus.gov/ency/article/000400.htm) (MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine), 2026).

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Source: https://durgical.com/en/conditions/thyroid-storm/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/thyroid-storm/