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Thyroid storm



Endocrine system


Adrenal gland disorders
Thyroid gland disorders
Parathyroid gland disorders
Pancreatic disorders
Pituitary gland disorders
Gonadal dysfunction
Polyglandular syndromes
Endocrine tumors
Endocrine system pathology review

Thyroid storm


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High Yield Notes
10 pages

Thyroid storm

9 flashcards

USMLE® Step 1 style questions USMLE

1 questions

A 47-year-old woman presents to the emergency department due to altered mental status. She is accompanied by her partner, who reports that the patient was in her usual state before having severe nausea and vomiting during dinner. Medical history is remarkable for long-standing Graves disease, but the patient has been non-compliant with medications. Last week, she had an upper respiratory infection that was resolved without treatment. Temperature is 40°C (104.0°F), pulse is 155/min and irregular, and blood pressure is 155/100 mmHg. On physical examination, the patient is agitated and in severe distress. The patient’s skin is moist, and a large goiter is noted. Laboratory tests show an elevated T3 and T4, low TSH, elevated liver enzymes, mild hyperglycemia, and leukocytosis. The patient is administered IV propranolol, propylthiouracil, and hydrocortisone. An hour later, the doctor adds a potassium iodide-iodine (Lugol's) solution to the treatment. This medication has which of the following immediate effects?  

External References

Content Reviewers:

Rishi Desai, MD, MPH

Thyrotoxic crisis, more commonly called thyroid storm, is a severe, acute complication of hyperthyroidism.

In hyperthyroidism, there’s an excess of thyroid hormone, and in thyroid storm the symptoms and physiologic effects of having excessive thyroid hormones are suddenly magnified.

Normally, the hypothalamus, which is located at the base of the brain, detects low blood levels of thyroid hormones and releases thyrotropin-releasing hormone into the hypophyseal portal system - which is a network of capillaries linking the hypothalamus to the anterior pituitary.

The anterior pituitary then releases thyroid-stimulating hormone, also called thyrotropin or simply TSH.

TSH stimulates the thyroid gland which is a gland located in the neck that looks like two thumbs hooked together in the shape of a “V”.

The thyroid gland is made up of thousands of follicles, which are small spheres lined with follicular cells.

Follicular cells convert thyroglobulin, a protein found in follicles, into two iodine-containing hormones, triiodothyronine or T3, and thyroxine or T4.

Once released from the thyroid gland, these hormones enter the blood and bind to circulating plasma proteins.

Only a small amount of T3 and T4 will travel unbound in the blood, and these two hormones get picked up by nearly every cell in the body.

Once inside the cell T4 is mostly converted into T3, and it can exert its effect.

T3 speeds up the basal metabolic rate.

So as an example, they might produce more proteins and burn up more energy in the form of sugars and fats. It’s as if the cells are in a bit of frenzy.

T3 increases cardiac output, stimulates bone resorption - thinning out the bones, and activates the sympathetic nervous system, the part of the nervous system responsible for our ‘fight-or-flight’ response.

Thyroid hormone is important - and the occasional increase is like getting a boost to fight off a hungry predator or to stay warm during a snowstorm!

Now, hyperthyroidism can happen a few different ways - all of them result in too much thyroid hormone and a hypermetabolic state, where cellular reactions are happening faster than normal.

The most common cause is Graves disease, an autoimmune disorder where B cells produce antibodies against several thyroid proteins.

These autoantibodies include thyroid-stimulating immunoglobulins, which bind to the TSH receptor on follicular cells and imitate TSH.

This results in growth of the thyroid gland and stimulates the follicular cells to produce excess thyroid hormone.

Another cause is toxic nodular goiter, where one or more follicles start generating lots of thyroid hormone - in some cases it’s because of a mutated TSH receptor that inappropriately keeps these follicular cells active.


Thyroid storm, also known as a thyrotoxic crisis, is a rare but life-threatening medical emergency caused by a sudden and severe worsening of hyperthyroidism (overactive thyroid). It is more common in individuals with untreated or poorly controlled hyperthyroidism and may be triggered by stress, infection, surgery, or other medical conditions.

Signs and symptoms include high fever, tachycardia, high blood pressure, agitation, confusion, sweating, vomiting, diarrhea, and in severe cases, seizures or coma. It can be fatal if left untreated, and prompt medical attention is necessary. The treatment involves medications like β-blockers, propylthiouracil, corticosteroids, and potassium iodide.

  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "Harrison's Endocrinology, 4E" McGraw-Hill Education / Medical (2016)
  5. "Thyroid emergencies" Polish Archives of Internal Medicine (2019)
  6. "Hyperthyroidism" The Lancet (2016)