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Thyroid Storm

Last updated Dec. 15, 2019

Approved by: Krish Tangella MD, MBA, FCAP

A Thyroid Storm is the result of excess thyroid hormone circulating in blood. This potentially serious condition is usually caused by an overactive thyroid gland.


What are the other Names for this Condition? (Also known as/Synonyms)

  • Accelerated Hyperthyroidism causing Thyroid Storm
  • Hyperthyroid Crisis
  • Thyrotoxic Storm

What is Thyroid Storm? (Definition/Background Information)

  • A Thyroid Storm is the result of excess thyroid hormone circulating in blood. This potentially serious condition is usually caused by an overactive thyroid gland
  • Thyroid Storm is a very rare condition that mostly affects young and middle-aged women. High levels of thyroid hormone is known to cause malfunctioning of the neuromuscular, gastrointestinal, reproductive, and cardio-respiratory systems
  • Untreated hyperthyroidism (overactive thyroid gland) in combination with a heart attack, trauma, and infection are the potential risk factors for Thyroid Storm
  • It is reported that 1-2% percent of the individuals with hyperthyroidism may be affected by a Thyroid Storm. The common signs and symptoms of Thyroid Storm include high fever, increased heart rate, irritability, confusion, tremors, vomiting and fatigue
  • Thyroid Storm is diagnosed by an assessment of clinical symptoms and measuring thyroid hormone levels in blood. Other similar conditions may have to be excluded prior to arriving at a diagnosis
  • It is typically treated using antithyroid medications, iodides, steroids, and beta-blocker drugs. Untreated Thyroid Storm can be life-threatening. However, with treatment, the mortality rate is reported to drop from 50-90% to about 11% and the prognosis is improved

Who gets Thyroid Storm? (Age and Sex Distribution)

  • Thyroid Storm is a very rare condition and most often seen in individuals with chronic, untreated hyperthyroidism
  • It can occur in individual of all ages, but is most commonly seen between the third and fourth decades (ages 20-40 years)
  • Women are 3-5 times more likely to be affected by Thyroid Storm than men
  • There is no particular preference observed and all racial and ethnic groups are at risk

What are the Risk Factors for Thyroid Storm? (Predisposing Factors)

The risk factors associated with Thyroid Storm include:

  • Chronic, untreated hyperthyroidism due to conditions such as Grave’s disease, solitary toxic adenoma, toxic multinodular goiter, and others
  • Female gender
  • Having endured a major event such as a heart attack, surgery, or infection, while already suffering from hyperthyroidism

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Thyroid Storm? (Etiology)

Thyroid Storm is caused by dangerously elevated levels of thyroid hormones (T3 and T4) in blood.

  • Normal levels of T3 and T4 is necessary for the proper functioning of certain vital organs in the body such as the brain, heart, liver, and kidneys
  • Elevated levels of T3 and T4 hormones cause numerous signs and symptoms and can lead to the disruption of these critical organs
  • An increased responsiveness to catecholamine (such as epinephrine and dopamine) is believed to play a role in the development of Thyroid Storm
  • Catecholamines are chemicals that cause increased heart rate, alertness, and blood pressure in the body. These chemicals are needed, at normal levels, for the proper functioning of the body

A Thyroid Storm usually occurs when a pre-existing hyperthyroid condition is exacerbated by other conditions such as:

  • Infection
  • Non-compliance with thyroid medication regimens
  • Trauma
  • Cardiac dysfunction (heart attack)
  • Overdosage of thyroid hormone medications, such as levothyroxine
  • Emotional stress
  • Surgery
  • Diabetic ketoacidosis
  • Postpartum hyperthyroidism
  • Hyperthyroidism can be also caused by taking iodine-containing compounds (such as iodine salt or common salt that has been fortified with iodine)

What are the Signs and Symptoms of Thyroid Storm?

There are 3 major symptoms of Thyroid Storm, which are referred to as the classic triad. These include:

  • High fever: The fever is usually higher than 101.3°F; sometimes, it may be even as high as 106°F
  • Tachycardia: Heart rate of over 140 beats/min
  • Impairment of the central nervous system causing associated signs and symptoms

Other general symptoms (some of which may be caused by central nervous system dysfunction) include:

  • Weight loss
  • Muscle weakness, tremors
  • Edema
  • Heat intolerance
  • Diarrhea
  • Vomiting and nausea, fatigue
  • Agitation, restlessness, and confusion, which may progress to delirium, psychosis, and eventually coma, if left untreated

Cardiovascular symptoms, which may include: 

  • Chest pain
  • Palpitations
  • Atrial fibrillation: Irregular and rapid heart beat
  • Pulmonary edema: Presence of fluid in the lungs
  • Congestive heart failure
  • Shortness of breath
  • Hypertension

How is Thyroid Storm Diagnosed?

Thyroid Storm in usually diagnosed by the following tests and procedures:

  • Complete physical examination with medical history evaluation
  • Examining the clinical signs and symptoms of the condition
  • Blood tests may show elevated T3 and T4 levels, increased T3 uptake, and TSH suppression, all of which are indicators of a Thyroid Storm

Other tests may include the following:

  • Elevated creatine kinase levels
  • Anemia (lower levels of red blood cells or hemoglobin)
  • Thrombocytopenia (low platelet count)
  • Electrolyte levels in the body (comprehensive metabolic panel blood test)
  • High white blood cell count
  • Kidney dysfunction
  • Urine analysis
  • Chest X-ray
  • Electrocardiogram to check the electrical activity of heart

There are other conditions that have similar symptoms and therefore, may mimic a Thyroid Storm. A differential diagnosis may have to be considered to rule-out the following conditions before a diagnosis is made:

  • Methamphetamine abuse
  • Septic shock
  • Neuroleptic malignant syndrome

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Thyroid Storm?

The potential complications of a Thyroid Storm may include:

  • Pulmonary edema, which is the presence of fluid in the lungs
  • Congestive heart failure
  • Gastrointestinal perforation
  • Sepsis

Death may occur, if the condition is left untreated.

How is Thyroid Storm Treated?

The treatment of Thyroid Storm may include one or more of the following measures:

  • Use of antithyroid drugs such as propylthiouracil and methimazole
  • Iodides to inhibit the release of thyroid hormone from the thyroid gland
  • Beta blockers, such as propranolol, to treat the symptoms of a Thyroid Storm
  • Medications to block the conversion of T4 to T3: T3 is the active form of thyroid hormone T4, which means that T4 has to be converted to T3 for the thyroid gland to function normally

Supportive measures to stabilize the condition of the individual may include:

  • Oxygen support
  • Correcting electrolyte abnormalities, such as abnormal levels of sodium and potassium, in blood
  • Ice packs, cooling blankets, and acetaminophen to control increased body temperatures

How can Thyroid Storm be Prevented?

Thyroid Storm occurs in individuals with uncontrolled hyperthyroidism. And hence, the best preventive method is in taking the prescribed medications regularly at correct dosages, to combat elevated levels of thyroid hormones.

What is the Prognosis of Thyroid Storm?

  • An untreated Thyroid Storm is usually fatal. However, with treatment, the mortality rate is reported to drop from 50-90% to about 11%
  • With timely and successful treatment, individuals may show significant recovery within 24 hours and a full recovery in a week’s time. In such cases, the prognosis of Thyroid Storm is good
  • Recurrence of the condition may be avoided with medications and periodic follow-up appointments 

Additional and Relevant Useful Information for Thyroid Storm:

  • The purpose of thyroid stimulating hormone (TSH) is to stimulate the thyroid gland to produce thyroxin (T4), which is then converted to triiodothyronine (T3), in the liver and thyroid gland

The following article links will help you understand the TSH, T3, and T4 laboratory tests:

http://www.dovemed.com/common-procedures/procedures-laboratory/thyroid-stimulating-hormone-tsh-test/

http://www.dovemed.com/common-procedures/procedures-laboratory/free-t3-blood-test/

http://www.dovemed.com/common-procedures/procedures-laboratory/free-t4-blood-test/

http://www.dovemed.com/common-procedures/procedures-laboratory/thyroid-panel-tests/

What are some Useful Resources for Additional Information?


References and Information Sources used for the Article:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: April 28, 2016
Last updated: Dec. 15, 2019