Perioperative Thyroid Storm: A Medical and Surgical Emergency

Abstract

Thyroid storm is rare, acute medical endocrine emergency. It is aggressive manifestation of the hyperthyroid state. If delayed or not treated can be fatal or cause severe disabilities. Historically thyroid storm was a common complication of toxic goiter and goiter surgery but recently more common in hyperthyroidism patients with acute illness or surgical intervention and inadequately treated hyperthyroid patients. There is usually precipitating factor that lead to thyroid storm, such as emergency surgery, extreme stress, or acute severe illness. Clinical manifestations involve major body organ dysfunctions and range from fever, dysrhythmias, heart failure, vomiting, diarrhea, jaundice, and convulsions to coma. The pathophysiology of thyroid storm is organ dysfunction due to excessive thyroid hormones. Thyroid storm is diagnosed by clinical presentation, Electrocardiogram (ECG), chest X-ray findings and thyroid point of care ultrasound (POCUS), and the scoring systems. Management should be started without delay. Apart from supportive care airway, breathing, circulation, and disability (ABCD) approach and antithyroid medications should be administered. Delay in management will increase morbidity and mortality. Initially, propylthiouracil (PTU), beta-blocker, iodine, steroids, and bile chelating agent are the treatment. The thyroid mortality ranges from 20 to 30%.

1. Introduction

Thyroid storm is an acute and rare life-threatening clinical condition, complicated manifestation of severe hyperthyroidism, with multiple organ involvement. It was described in 1926 that thyroid storm had high morbidity and mortality, despite advancement in medical sciences. Hence it is essential to recognize this life-threatening syndrome early and manage it earlier to improve patient’s outcome. It is equally important that acute care physicians, surgeons and general practitioners, intensivists, and paramedical staffs are accustomed to the presentation and management of this rare endocrine disease [1].

2. Epidemiology

Thyroid storm is a rare presentation of hyperthyroidism. It accounts for 1–2% of hyperthyroidism admission. The reported incidence of thyroid storm in United States of America (USA) ranges from 0.5 to 0.7% cases/100,000 of normal population per year, where it is 4.8 to 5.6% /100,000 hospitalized patients [2]. The incidence of thyroid storm from Japan is 0.2/100,000 population per year. The thyroid storm patients were younger (42–43 years) and male to female ratio was 1:3 [3].

3. Precipitating factors

There are number of factors that may lead to the thyroid storm [4], described in the following Table 1.

Sudden stoppage of antithyroid medications

Trauma/Thyroid surgeries

Acute illness (Myocardial infarction, cerebrovascular accidents, sepsis, emergency surgery)

Parturition

iodinated contrast

Burns

Amiodarone, salicylate and anesthetics

Hyperemesis gravidarum

Radiation exposure

Table 1.

Precipitating factors for the thyroid storm.

The addition to above mentioned precipitating factors for thyroid storm, the severe emotional distress, and extreme stress can also lead to thyroid storm in hyperthyroid patients.

3.1 Pathophysiology of thyroid storm

Thyroid storm pathophysiology is summarized in Figure 1.

Figure 1.

Pathophysiology of thyroid storm.

Several theories are proposed for thyroid storm. A precipitating factor is always required to initiate thyroid storm, the most accepted hypothesis is that rapid, sudden increase in thyroid hormone levels, thus free hormones released from the protein-bound hormones, causing sudden increase in body metabolism, thus causing an exaggerated signs and manifestations of hyperthyroidism with multiple organs dysfunction (Table 1).

The histopathologic findings depend upon the etiology of thyroid storm, if it is due to Graves’ disease goiter, the histopathology will show diffuse follicular hyperplasia along with increased receptor antibodies with increased vascularity. If thyroid storm is due to malignancy, the histopathology will reveal ruptured follicles with malignant cells inhibition with disturbs of thyroid cells [5].

3.2 Etiology

The thyroid storm commonly occurs in Graves’ disease, toxic adenoma, and the multi-nodular toxic goiter. The exact etiology of thyroid storm is not known, there will be always a precipitating factor and the extremes of stress concurrent, systemic acute illness such as sepsis or increasing incidence with emergency surgery.

3.3 Clinical presentation

Patient thyroid storm will have exaggerated hyperthyroidism signs and symptoms. Fever, tachycardia, tachyarrhythmias and heart failure, central nervous system (CNS), and Gastrointestinal (GI) manifestations are frequent. The CNS manifestations will be agitation, delirium, anxiety, and coma. The GI symptoms are nausea, vomiting, diarrhea, intestinal obstruction, and hepatic failure. Examinations will reveal orbitopathy, goiter, hand tremors, moist and warm skin, and jaundice [6].

Common signs and symptoms are summarized in the following Table 2.

Thyrotoxicosis	Thyroid storm
Heat intolerance and diaphoresis	Hyperpyrexia, temperature > 106F with dehydration
Sinus tachycardia; Heart rate 100 to 140/minute	Heart rate > 140; Tachyarrhythmias; Hypertension; Congestive heart failure
Diarrhea, increased appetite with weight loss	Nausea, vomiting, diarrhea, jaundice
Anxiety, restlessness	Agitation, confusion, delirium, seizures, and coma

Table 2.

Common signs and symptoms for thyrotoxicosis and thyroid storm.

3.4 Diagnosis

Thyroid storm should be suspected from clinical presentations in hyperthyroidism or suspected hyperthyroidism patients. Laboratory workup will show low thyroid stimulating hormone (TSH) and high T3/T4 levels. Patient will have hyperglycemia, hypercalcemia, leukocytosis, and abnormal liver function test. Various scoring systems for the diagnosis of thyroid storm are described in Tables 3 and 4 [8].

Burch–Wartofsky Point Scale (BWPS)
Variables	Points
Temperature	5 points per 1 °F above 99°F (maximum 30 points)
CNS dysfunction: Agitation; Delirium/lethargy; Seizure/coma	10 points; 20 points; 30 points
Tachycardia; 99–109/minute; 110–119/minute; 120–129/minute; 130–139/minute; >140/minute	5 points; 10 points; 15 points; 20 points; 25 points
Arterial fibrillation	10 points
GI dysfunction; Vomiting/diarrhea; Jaundice	10 points; 20 points
Heart failure; Pedal edema; bi-basilar rales; pulmonary edema	5 points; 10 points; 15 points
Presence of precipitating factor	10 points

Table 3.

Burch–Wartofsky point scale (BWPS) scoring systems for thyroid storm.

Diagnosis: Needs BWPS score of 45 or more to diagnose thyroid storm.

Score of 25 to 45 may indicate impending thyroid storm.

Score less than 25 makes the diagnosis unlikely.

Elevated T3/T4

Fever (38 ^©C/100.4 °F or greater)

Central nervous system (CNS) manifestation will be restlessness, delirium, psychosis/mental aberration, lethargy/somnolence, coma

Heart rate (130/min or higher)

Congestive heart failure (pulmonary edema to cardiogenic shock)

GI Manifestation (from vomiting to jaundice)

Table 4.

JTA scoring [7].

According to the Japanese thyroid association (JTA), it is essential to diagnose thyroid storm by the elevated free T3 or T4 with one CNS manifestation and pulmonary symptoms along with fever, congestive heart failure (CHF), and tachycardia or combination of three features fever, GI/hepatic and congestive heart failure (CHF) or tachycardia. The JTA scoring system is more specific in diagnosis of thyroid storm.

Chest X-ray may show pulmonary congestion or pulmonary edema or cardiomegaly. ECG should be done which may reveal sinus tachycardia or tachyarrhythmia. Bedside POCUS may reveal a hypervascular thyroid gland (Figure 2). Patient may be breathless or short of breath and or hypotensive.

Figure 2.

POCUS showing hypervascular left lobe of thyroid gland.

3.5 Management

One should not waste golden time in waiting for laboratory results, as thyroid storm is a medical emergency. Thyroid storm patients may present in shock, we should follow airway, breathing, circulation, deficit and exposer (ABCDE) approach and manage either cardiogenic or other dehydration causing hypovolemic shock in these patients. We should have continuous supportive management with advanced hemodynamic monitoring with intravenous fluids, core body temperature management, if required vasopressor and inotropes. These patients may have tachyarrhythmias and should be managed as per acute life support (ALS) protocol. These patients with thyroid storm need intensive care therapy unit admission and management.

The specific management strategies of thyroid storm are described in the following points.

1. Beta-blockers to control increased adrenergic tones.

2. Thioamide to reduce thyroid hormone synthesis.

3. Iodine solutions to reduce the release of thyroid hormones.

4. Glucocorticoid, PTU, and propranolol to reduce or block peripheral conversion of T4 to T3.

5. Bile acid sequestrant to reduce the enterohepatic recycling of thyroid hormones.

After ABCDE of supportive care, a beta-blocker should be started. Usually, propranolol 40–80 mg every 4 to 6 hours is administered.

PTU loading dose up to 1000 mg and followed by 250 mg every 4 hours or methimazole can be administered. PTU is preferred as it also has additional action of blocking peripheral conversion of T4 to T3. After 1 hour of PTU administration, 5 drops of supersaturated potassium iodide (SSKI) should be given per oral and repeat 6 hourly. This will prevent increase in synthesis of thyroid hormone due to iodine administration [9]. Hydrocortisone or dexamethasone, 100 mg intravenously and 2 mg Q 6 hourly respectively should also start. Cholestyramine 4 grams, 3 to 4 times will prevent enterohepatic recycling of thyroid hormones. Aspirin increases thyroid hormone levels and should be avoided in thyroid storm in these patients.

PTU decreases T3 by 45% in initial 24 hours of treatment. The methimazole causes more rapid normalization of T3 after weeks of treatment. Hence after initial stabilization, PTU should be changed to methimazole, if patient cannot take these medications orally can be given, and liquid preparation of the medications can be administered rectally. Patients with Graves’ disease should be pretreated with beta-blocker, iodine therapy, and antithyroid medication before undergoing surgical intervention.

These medications are contraindicated due to allergy, thyroidectomy is required after treatment with Beta-blocker, steroids, cholestyramine, and iodine administration. The plasmapheresis should be the last resort if above measures fail [10].

4. Morbidity and mortality

Thyroid storm is fatal if not treated, usually heart failure, arrhythmias, or multiorgan failure leads to the death. If treatment starts, patients improve within 24 hours. The advanced age, neurological dysfunction upon admission, failure or delayed use of antithyroid medications or beta-blockers, requiring dialysis or mechanical ventilator increases the risk of death with poor prognosis [11].

5. Conclusion

Thyroid storm is an endocrine medical emergency, requiring early diagnosis and earlier management. Frequent precipitated by stress or acute illness or improper treatment of hyperthyroidism.

Thyroid storm or increased level of thyroxine or thyroid hormones causes multiple organ dysfunction or failure. Commonly manifested as fever, GI, central nervousness and cardiac dysfunctions, and arrhythmias. Thyroid storm diagnosed by clinical presentation, high index of suspicious, and use of scoring system. These patients can present in shock. Management should be supportive care, use of antithyroid medications, management of shock, antiarrhythmic therapy, and temperature management. Advanced age, neurological dysfunction at presentations, requirement of dialysis, invasive ventilation, and delay in antithyroid therapy will indicate a poor prognosis in thyroid storm.