Thyroid Storm - Causes,Symptoms,Diagnosis, and Treatment

Introduction:

A thyroid storm is an acute, critical, and life-threatening condition resulting from undiagnosed or untreated hyperthyroidism. The condition is characterized by high levels of thyroid hormones in the blood, leading to a thyroid crisis. The condition is extremely rare, and it is often associated with a hyperthyroidism disorder, Graves’ disease. The condition is more common in females and affects middle-aged individuals. A thyroid storm presents with multiple systemic symptoms involving the heart, nervous system, stomach, and intestine. The condition requires immediate treatment; otherwise, it can lead to possible complications like coma or death.

What Is a Thyroid Gland?

The thyroid is a very important gland of the body that is classified as an endocrine gland. The thyroid is a small gland located in front of the neck. It consists of two lobes that are present on either side of the trachea (the windpipe), just below the larynx (the voice box). The thyroid gland is responsible for the production of thyroxine (T4), triiodothyronine (T3), and calcitonin. These thyroid hormones carry out some crucial functions of the body like growth, development, metabolism and other such functions.

What Is a Thyroid Storm?

A thyroid storm is a rare, acute, and potentially life-threatening condition that occurs due to untreated hyperthyroidism or thyrotoxicosis, with too much thyroid hormone in the body. A thyroid storm is considered a complication of untreated hyperthyroidism. The condition is characterized by high-grade fever, tachycardia (increased heartbeat), arrhythmia (irregular heartbeat), increased blood pressure, nausea, diarrhea, and agitation (rage). Around 8 to 25 percent of the people affected by thyroid storms die. The condition progresses in three stages; early, mid, and late crisis. In the later stage, the condition becomes severe and almost unmanageable. Thyroid storm is generally associated with long-term untreated Graves’ disease (immune disorder with overproduction of the thyroid hormones). Thyroid storms are mostly reported in middle-aged people over 40 years. Females are more likely to develop thyroid storms as compared to males.

What Are the Other Names of Thyroid Storm?

Several other names of thyroid storm are:

• Thyrotoxicosis crisis.

• Thyrotoxicosis storm.

• Hyperthyroid storm.

• Accelerated hyperthyroidism.

• Thyroid crisis.

What Causes Thyroid Storm?

The thyroid storm occurs primarily as a complication of undiagnosed and untreated hyperthyroidism. The condition is often associated with Graves’ disease, but several other causes can predispose thyroid storm:

• Sudden discontinuation of the anti-thyroid medication.

• Thyroid surgery.

• Non-thyroid surgery.

• Trauma.

• Stress.

• Presence of another systemic disease.

• Infection.

• Acute illness.

• Diabetic ketoacidosis (a life-threatening complication of diabetes that occurs when there is not enough insulin in the body).

• Hypoglycemia (reduced blood sugar levels).

• Tumor of the ovaries (Struma ovarii).

• Pulmonary embolism (Blood clots get lodged in an artery of the lungs resulting in blocked blood flow in that part of the lungs).

• Heart attack (blood flow to the heart muscles gets blocked).

• Stroke (blood flow to the brain is interrupted).

• Cardiac failure.

• Side effects of medications like anesthetics, salicylates, Amiodarone and others.

• Giving birth.

• Excess or recent use of iodinated contrast medium (often used to diagnose thyroid diseases).

• Burns.

• Rarely, radioiodine therapy can also cause thyroid storms.

How Common Is a Thyroid Storm?

• A thyroid storm is a rare condition.

• Approximately 1 to 2 percent of people with hyperthyroidism need hospital admission due to a thyroid storm.

• The incidence of thyroid storms in the United States of America is about 0.57 to 0.76 cases per 1,00,000 people per year.

• And the incidence in the hospitalized population is around 4.8 to 5.6 cases per 1,00,000 admissions per year.

• The male-to-female ratio of incidence is 1:3, meaning females are three times more likely to be affected by thyroid storms than males.

What Are the Symptoms of Thyroid Storm?

The clinical symptoms of thyroid storm occur due to exaggerated effects of the thyroid hormones. Due to intense metabolic activities, the body has an increased requirement for oxygen. This increased oxygen requirement leads to an increased heartbeat in order to meet the oxygen demand. This tachycardia can induce heart failure and arrhythmias. Moreover, various symptoms of thyroid storm include:

• Agitation and irritability.

• High-grade fever, along with excess sweating.

• Restlessness and altered alertness.

• Increased heartbeat or pounding of heart, more than 140 beats per minute.

• Shaking and tremors.

• Diarrhea.

• Increased blood pressure in the early and mid-crisis followed by extremely low blood pressure in the late stage of the thyroid crisis.

• Central nervous system involvement shows symptoms like delirium (disturbed mental abilities), psychosis, etc.

• Coma in later stages.

• Symptoms of organ dysfunction like jaundice in the case of liver dysfunction.

• Cardiac symptoms like heart attack, stroke (a condition where the blood supply to the brain is compromised due to trauma or blood clot), etc.

• Gastrointestinal symptoms like abdominal pain, intestine obstruction, etc.

• Bulging of the eyes.

How Does Thyroid Storm Occur?

The exact mechanism of development of thyroid storm in an individual is poorly understood; however, there are certain speculation and suggestion by various studies that thyroid storm can occur in the following ways:

• Increase in the availability of free thyroid hormone. Although the total thyroid hormone level may not exponentially increase, a rise in the availability of free thyroid hormone can result from the change in the thyroid gland.

• Decrease in the levels of thyroid hormone-binding protein, which eventually causes a rise in the free thyroid hormone.

• Increased sensitivity to the thyroid hormones, along with increased availability of thyroid hormones, can lead to thyroid storms.

• Sympathetic nervous system (the nervous system responsible for flight-or-fight response) activation in stressful situations increases the production of thyroid hormones by the thyroid gland. Therefore, there is an increase in thyroid hormone receptors which, in turn, increases response to catecholamines (hormones made by adrenal glands). This mechanism is thought to be responsible for the several cardiovascular symptoms that occur during a thyroid storm.

How Is Thyroid Storm Diagnosed?

The diagnosis of thyroid storm can be made in the following ways:

• Laboratory Tests: Doctors would usually not wait until the reports of blood examinations come to start the treatment of a thyroid storm. However, the blood reports in case of thyroid storm will show the following results:

1. High levels of fT4 (free thyroxine) and fT3 (free triiodothyronine).

2. Reduced levels of thyroid-stimulating hormone (TSH).

3. There may not be a very high level of thyroid hormones reported.

4. Hypercalcemia (increased level of calcium in the blood).

5. Hyperglycemia (increased blood sugar levels).

6. Abnormal values in a liver function test report.

7. Unusually high or unusually low white blood cell (WBCs) count.

• In 1993, a scoring system for evaluating thyroid storms was introduced, known as the Burch-Wartofsky point scale. This evaluation calculates the Burch-Wartofsky score depending on the combination of symptoms.

• Symptom:

  • Temperature- Score-5 points per one-degree increase in the temperature above 99 Fahrenheit. (for example, 99.0 to 99.9 Fahrenheit will contribute 5 scores).

  • Central Nervous System Dysfunction- Mild agitation - 10 scores, moderate psychosis, delirium - 20, and seizures and coma - 30.

  • Tachycardia or Increased Heartbeat- 99 to 109 bpm (beats per minute) - 5 scores, 110 to 119 bpm - 10 scores, 120 to 129 bpm - 15 scores, 130 to 139 bpm - 20 scores, and greater than 140 bpm - 25 scores.

  • Atrial Fibrillation (Irregular and Rapid Heartbeat)- If present, 10 scores.

  • Heart Failure- Mild - 5 scores, moderate - 10 scores, and severe - 15 scores.

  • Gastrointestinal Dysfunction- Moderate - 10 scores and severe - 20 scores.

  • Other Factors: Presence of other factors that could have led to a thyroid storm- 10 scores.

A Burch-Wartofsky score of less than 25 suggests the absence of any thyroid storm, between 25 to 40 suggests expecting a thyroid storm, and a score above 40 suggests the presence of a current thyroid storm.

• Imaging tests like X-ray or CT (computed tomography) scans may be done to see the presence of heart failure.

• Electrocardiogram (ECG) or echocardiogram may be done to monitor the arrhythmia.

How Is Thyroid Storm Treated?

The treatment of a thyroid storm is done in the following ways:

• Immediate supportive treatments like intravenous fluids, oxygen, cooling blankets, Acetaminophen (medication used to treat fever and pain), controlling precipitating factors like infection, etc., should be immediately employed.

• The main treatment modality for managing a thyroid storm is to lower the levels of excess thyroid hormones in the body. For this, inorganic iodine is used to reduce the production and release of thyroid hormones. It should be given after antithyroid drugs have been given to the patient.

• Antithyroid drugs like Propylthiouracil and Methimazole are used to reduce the synthesis and release of thyroid hormones by the thyroid glands.

• Beta-blockers are used to reduce the effect of circulating thyroid hormones on other organs. Moreover, beta-blockers also reduce the conversion of thyroxine into its more active form, triiodothyronine. Beta-blockers also reduce the adrenergic tone (organs and nerves in which adrenaline and noradrenaline act as neurotransmitters).

• Corticosteroids may be used to treat the cortisol deficiency which occurs in case of a thyroid storm. High levels of thyroid hormone increase metabolic activities, which increases the hormone cortisol's breakdown.

• If the cause of the condition is a thyroid adenoma or toxic multinodular goiter, then surgical resection and radioactive iodine therapy are the treatment of choice.

Conclusion:

The treatment for thyroid storm should be immediate and prompt. The healthcare provider should not wait for the blood reports to start the treatment. The condition is severe and life-threatening therefore waiting until laboratory reports come can lead to the patient’s death. The healthcare provider should study the presenting symptoms and the patient’s medical history to evaluate the presence of the thyroid storm and start the treatment accordingly. Any delay or carelessness in the treatment can cause complications like coma or death.