Thyrotoxic Crisis (Thyroid Storm)
A life-threatening surge of an overactive thyroid
Quick Facts
- Type: Endocrine emergency
- Underlying cause: Severe hyperthyroidism, often Graves disease
- Hallmarks: High fever, racing heart, confusion
- Action: Call emergency services immediately
Overview
Thyrotoxic crisis, often called thyroid storm, is a rare but life-threatening emergency in which the effects of an overactive thyroid become dangerously severe. The thyroid gland controls the body's metabolism, and in this condition an extreme excess of thyroid hormone activity pushes the heart, temperature, and nervous system to dangerous extremes.
It almost always develops in someone who already has hyperthyroidism, frequently from Graves disease, especially when the condition is untreated, undertreated, or stressed by another illness, surgery, or infection. Without prompt treatment, thyroid storm can be fatal, so it is treated as a medical emergency. Anyone with a known overactive thyroid who suddenly becomes very unwell with fever and a racing heart needs urgent care.
Symptoms
Thyrotoxic crisis is an extreme, rapidly worsening version of overactive thyroid symptoms. Warning signs include:
- High fever, often above 38.5°C (101°F)
- A very fast or irregular heartbeat and palpitations
- Agitation, anxiety, confusion, or delirium
- Profuse sweating
- Nausea, vomiting, and diarrhea
- Tremor and severe weakness
- In severe cases, drowsiness, coma, or signs of heart failure
These symptoms come on quickly and the person becomes seriously ill. This is an emergency that requires calling emergency services right away.
Causes and Triggers
Thyroid storm arises from a large excess of thyroid hormone effect in the body, almost always on a background of pre-existing hyperthyroidism. It is often set off by a stress or trigger, such as:
- Infection or other acute illness
- Stopping thyroid-controlling medication
- Surgery, including thyroid surgery, or trauma
- Childbirth
- Poorly controlled diabetes or other metabolic stress
- Rarely, a large dose of thyroid hormone or iodine
The underlying overactive thyroid is most often from Graves disease, an overactive thyroid nodule, or thyroid inflammation.
Risk Factors
- Untreated or poorly controlled hyperthyroidism
- Graves disease
- Stopping antithyroid medication
- A recent infection, surgery, or serious illness
- Recent childbirth in someone with thyroid disease
- Lack of access to ongoing thyroid care
Diagnosis
Thyroid storm is recognized clinically because treatment cannot wait for all test results. Doctors use:
- Clinical assessment: The combination of severe symptoms (high fever, fast heart, confusion) in someone with known or suspected hyperthyroidism.
- Thyroid blood tests: Showing very high thyroid hormone and low thyroid-stimulating hormone (TSH), though levels may overlap with ordinary hyperthyroidism.
- Other tests: To find a trigger such as infection, and to check the heart and other organs.
Because it is life-threatening, treatment is started on clinical grounds as soon as it is suspected.
Treatment
Thyrotoxic crisis is treated in hospital, often in intensive care, with several therapies given together:
- Blocking thyroid hormone: Antithyroid medicines to stop further hormone production, sometimes with iodine to reduce hormone release.
- Slowing the heart: Beta-blockers to control the racing heart and many of the symptoms.
- Steroids: To help reduce the conversion and effects of thyroid hormone and support the body's stress response.
- Cooling and supportive care: Lowering fever, giving fluids, and supporting the heart and other organs.
- Treating the trigger: Such as antibiotics for infection.
With rapid, intensive treatment, many people recover, after which the underlying overactive thyroid is treated definitively to prevent another crisis.
Prevention
- Take antithyroid medication exactly as prescribed and do not stop it without medical advice
- Keep regular follow-up and blood tests for an overactive thyroid
- Seek prompt treatment for infections and other illnesses
- Tell all health professionals about your thyroid condition before surgery or procedures
- Complete definitive treatment of hyperthyroidism when advised
When to See a Doctor
Thyrotoxic crisis is a medical emergency. Call emergency services immediately if a person with a known or suspected overactive thyroid suddenly develops:
- High fever with a racing or irregular heartbeat
- Confusion, agitation, or reduced consciousness
- Severe sweating, vomiting, or diarrhea with weakness
- Signs of heart failure such as severe breathlessness
Do not wait for symptoms to settle. Earlier, see a doctor promptly if you have hyperthyroidism that is poorly controlled, and never stop your thyroid medication on your own.
Frequently Asked Questions
What is thyrotoxic crisis or thyroid storm?
It is a rare, life-threatening emergency where the effects of an overactive thyroid become extreme, causing high fever, a racing heart, and confusion. It usually develops in someone with hyperthyroidism and needs immediate emergency treatment.
What triggers a thyroid storm?
It is often set off by infection, surgery, trauma, childbirth, or stopping antithyroid medication in a person who already has an overactive thyroid, most commonly from Graves disease.
Is thyroid storm an emergency?
Yes. It can be fatal without prompt treatment. Anyone with a known or suspected overactive thyroid who develops high fever, a racing or irregular heartbeat, and confusion needs emergency services called right away.
How is thyroid storm treated?
Treatment is given in hospital, often intensive care, and combines antithyroid medicines, beta-blockers to slow the heart, steroids, cooling, fluids, and treatment of any trigger such as infection.
How can thyroid storm be prevented?
Taking antithyroid medication as prescribed, never stopping it without advice, keeping regular follow-up, treating infections promptly, and completing definitive treatment of an overactive thyroid all lower the risk.
References
- Mayo Clinic. Hyperthyroidism (overactive thyroid).
- MedlinePlus, U.S. National Library of Medicine. Thyroid storm.
- American Thyroid Association. Hyperthyroidism.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Hyperthyroidism.