Thyroid storm is a life-threatening exacerbation of hyperthyroidism that can develop in patients with undiagnosed or untreated hyperthyroidism when stressed. It is characterized by worsening signs and symptoms of thyrotoxicosis including cardiac dysfunction, hyperglycemia, altered mental status, and seizures. Diagnosis is based on clinical features and scoring systems, with a Burch-Wartofsky score of over 45 suggestive of thyroid storm. Treatment involves supportive care, administration of beta blockers, antithyroid medications, iodine, and glucocorticoids to reduce thyroid hormone levels and symptoms.
4. INTRODUCTION
The thyroid gland is one of the largest endocrine glands.
Thyroxine (T4) and triiodothyronine (T3) are under tight control
of thyroid-stimulating hormone (TSH) from the pituitary gland.
Twenty times more T4 is produced by the thyroid gland than T3.
However, T3 is the more active form and produces almost all the
clinical effects.
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5. Introduction
Thyroid hormones :
T3 , T4 and Calcitonin (regulates calcium levels in the plasma).
Thyroid hormones are lipophilic and able to cross the cell membrane to act directly
on cytoplasmic pathways. They are transported in the plasma bound to specific
globulins, albumin, and other plasma proteins and have longer half-lives.
T4 is converted to T3 in the periphery by deiodination ,
where it exerts its effects.
Thyroid increases metabolic rate and heat production, has sympathomimetic effects
and maintain the level of metabolism in the tissues that is optimal for their normal
function.
Thyroid contains 95% of the total Iodine content in the body.
5
6. It is the free thyroid hormones in plasma that
are physiologically active and that feed back to
inhibit pituitary secretion of TSH.
The function of protein-binding appears to be the
maintenance of a large pool of hormone that can
readily be mobilized as needed.
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7. THYROID
STORM
(Known also as Thyrotoxic Crises)
All patients with thyrotoxicosis should be
considered to be at risk of developing
thyroid storm.
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8. THYROID STORM
Thyroid storm is a life-threatening exacerbation of
hyperthyroidism that most commonly develops in the
undiagnosed or untreated hyperthyroid patient because
of the stress of surgery or nonthyroid illness.
It is an acute severe hypermetabolic state induced by excessive
release of thyroid hormones ,
Free T4 level is markedly elevated , (Normally T4 is 99.98%
bound to plasma proteins).
It has a ~30% mortality rate despite of treatment.
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9. THYROID STORM
Thyroid storm is characterized by worsening of the
signs and symptoms of thyrotoxicosis, including :
Cardiac dysfunction
Hyperglycemia
Hypercalcemia,
Hyperbilirubinemia,
Altered mental status
Seizures, and coma
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10. THYROID STORM
The major risk of anesthesia in the poorly
controlled thyrotoxic patient is thyroid storm,
which must be aggressively treated with β-
blockers, iodide, and antithyroid drugs.
it is essential to remove or treat the
precipitating event.
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12. Thyroid Storm triggered in a thyrotoxic patient by any
one of several stresses
Infection (The commonest cause).
Stroke.
Trauma, especially to the Thyroid Gland.
(Delikoukos, S. and F. Mantzos, Thyroid storm induced by blunt thyroid gland trauma.
Am Surg, 2007. 73(12): p. 1247-9.)
Hypoglycemia and Diabetic Ketoacidosis .
Drugs : Pseudoephedrine, Aspirin, Excess Iodine Intake, NSAIDs ,
Iodine Contrast Dye & Amiodarone (Cordarone).
Incorrect Anti-Thyroid Drug Discontinuation .
Surgery under unrecognized or inadequately treated thyrotoxicosis.
Sepsis & Acute illness.
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13. THYROID STORM TRIGERRING STRESSES
Vigorous palpation of an enlarged thyroid
Induction of anesthesia
Radioactive iodine (RAI) therapy
Toxemia of pregnancy and labor in older adolescents; molar pregnancy
Hyperfunctioning thyroid nodule
Hyperfunctioning multinodular goiter
Thyroid-stimulating hormone (TSH)-secreting tumor
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15. THYROID STORM
Thyroid storm is an endocrine emergency that is
characterized by rapid deterioration within days or
hours of presentation and is associated with high mortality.
The diagnosis of thyroid storm is based on clinical features
and no specific laboratory tests are available.
If the patient's clinical picture is consistent with thyroid storm,
do not delay treatment for pending laboratory confirmation of
thyrotoxicosis.
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16. Thyroid Storm Clinical Presentation
Patients may have a known history of thyrotoxicosis.
General symptoms:
Fever (> 38.5 degree Celsius)
Profuse sweating
Poor feeding and weight loss
Respiratory distress
Fatigue (more common in older adolescents)
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17. Thyroid Storm Clinical Presentation
GI symptoms
Nausea and vomiting
Diarrhea
Abdominal pain
Jaundice
(Hasan MK, Tierney WM, Baker MZ. Severe cholestatic jaundice in hyperthyroidism
after treatment with 131-iodine. Am J Med Sci. 2004 Dec. 328(6):348-50).
Neurologic symptoms
Anxiety (more common in older adolescents)
Altered behavior
Seizures, coma
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18. Physical Examination
Fever
Temperature consistently exceeds 38.5°C.
Patients may progress to hyperpyrexia.
Temperature frequently exceeds 41°C.
Excessive sweating.
Cardiovascular signs
o Hypertension with wide pulse pressure.
o Hypotension in later stages with shock.
o Tachycardia disproportionate to fever.
o Signs of high-output heart failure.
o Cardiac arrhythmia (Supraventricular arrhythmias are more common,
[e.g., atrial flutter and fibrillation] , but ventricular tachycardia may also occur.)
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19. Physical Examination
Neurologic signs
o Agitation and confusion
o Hyperreflexia and transient pyramidal signs
o Tremors, seizures
o Coma
Signs of thyrotoxicosis
o Orbital signs
o Goiter
Rhabdomyolysis
Rare cases have been reported following a diagnosis of thyroid storm in adults
(Umezu T, Ashitani K, Toda T, Yanagawa T. A patient who experienced thyroid storm complicated by
rhabdomyolysis, deep vein thrombosis, and a silent pulmonary embolism: a case report.
BMC Res Notes. 2013 May 20. 6(1):198.)
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21. Diagnosis of Thyroid Storm
The distinction between thyrotoxicosis and thyroid storm is a challenge.
Clinical scoring systems can be used as a guide .
One example assigns points for temperature (up to 30), central
nervous system effects (up to 30), gastrointestinal dysfunction (up to 20),
and cardiovascular signs and symptoms (up to 50).
The points are summed and a total of 45 or above is considered suggestive of
thyroid storm , a score between 25 and 44 indicates impending storm and a score
below 25 storm is unlikely.
(Nayak, B. and K. Burman, Thyrotoxicosis and thyroid storm.
Endocrinol Metab Clin North Am, 2006. 35(4): p. 663-86, vii.)
21
22. The Burch-Wartofsky Point Scale for diagnosis of
thyroid storm
Criteria Points
Thermoregulatory dysfunction
Temperature (˚C)
37.2–37.7 5
37.8–38.3 10
38.4–38.8 15
38.9–39.3 20
39.4–39.9 25
≥ 40.0 30
Cardiovascular
Tachycardia (beats per minute)
90–109 5
110–119 10
120–129 15
130–139 20
≥ 140 25
criteria Points
Atrial fibrillation
Absent 0
Present 10
Congestive heart failure
Absent 0
Mild 5
Moderate 10
Severe 15
22
23. Scale for diagnosis of thyroid storm
Criteria Points
Gastrointestinal-hepatic dysfunction
Manifestation
Absent 0
Moderate (diarrhea, abdominal pain,
nausea/vomiting) 10
Severe (jaundice) 20
Central nervous system disturbance
Manifestation
Absent 0
Mild (agitation) 10
Moderate (delirium, psychosis,
extreme lethargy) 20
Severe (seizure, come) 30
Criteria Points
Precipitating event
Status
Absent 0
Present 10
Total score
≥ 45 Thyroid storm
25–44 Impending thyroid storm
< 25 Thyroid Storm is unlikely
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25. The diagnostic criteria for thyroid storm (TS) of the Japan Thyroid
Association
Prerequisite for diagnosis
Presence of thyrotoxicosis with elevated levels of free triiodothyronine (FT3)
or free thyroxine (FT4).
Symptoms
1. Central nervous system (CNS) manifestations: Restlessness, delirium, mental
aberration/psychosis, somnolence/lethargy, coma ( ≥1 on the Japan Coma Scale or ≤14 on the
Glasgow Coma Scale).
2. Fever : ≥ 38˚C.
3. Tachycardia : ≥ 130 beats per minute or heart rate ≥ 130 in atrial fibrillation.
4. Congestive heart failure (CHF) : Pulmonary edema, moist rales over more than half of the
lung field, cardiogenic shock, or Class IV by the New York Heart Association (NYHA) .
5. Gastrointestinal (GI)/hepatic manifestations : nausea , vomiting, diarrhea, or
a total bilirubin level ≥ 3.0 mg/dl.
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26. The diagnostic criteria for thyroid storm (TS) of the Japan
Thyroid Association
Grade of TS Combinations of features Requirements for diagnosis :
TS1 First combination Thyrotoxicosis and at least one CNS manifestation and fever,
tachycardia, CHF, or GI/hepatic manifestations
TS1 Alternate combination Thyrotoxicosis and at least three combinations of fever,
tachycardia, CHF, or GI/hepatic manifestations.
TS2 First combination Thyrotoxicosis and a combination of two of the following:
fever, tachycardia, CHF, or GI/hepatic manifestations.
TS2 Alternate combination Patients who met the diagnosis of TS1 except that serum FT3
or FT4 level are not available.
(TS1, “Definite” Thyroid Storm; TS2, “Suspected” Thyroid Storm.)
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27. The diagnostic criteria for thyroid storm (TS) of the Japan Thyroid
Association
Exclusion and provisions
Cases are excluded if other underlying diseases clearly causing any of
the following symptoms: fever (e.g., pneumonia and malignant hyperthermia),
impaired consciousness (e.g., psychiatric disorders and cerebrovascular
disease), heart failure (e.g., acute myocardial infarction), and liver disorders
(e.g., viral hepatitis and acute liver failure).
Therefore, it is difficult to determine whether the symptom is caused by TS
or is simply a manifestation of an underlying disease; the symptom should be
regarded as being due to a TS that is caused by these precipitating factors.
Clinical judgment in this matter is required.
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32. LAB
Results of thyroid studies are usually consistent with hyperthyroidism and
are useful only if the patient has not been previously diagnosed .
Raised T3 & T4.
Decreased TSH.
Hyperglycemia, elevated alkaline phosphatase,
mild hypercalcemia and elevated liver enzymes.
Elevated 24-hour iodine uptake.
Mild leukocytosis.
Hyper-bilirubinemia : patient prognosis is worse when
total bilirubin levels are ≥3.0 mg/dL .
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33. Imaging Studies
CHEST RADIOGRAPHY :
Myocardial hypertrophy.
Pulmonary edema secondary to heart failure.
Evidence of pulmonary infection.
Head CT scanning :
To exclude other neurologic
conditions in suspected cases.
Airway problems
Lateral view of neck X-ray showing the compression of trachea from
a longstanding enlarged goiter .
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34. Other Tests
ECG
Is useful in monitoring for cardiac arrhythmias.
Atrial fibrillation is the most common cardiac
arrhythmia associated with thyroid storm.
Other arrhythmias such as atrial flutter and,
less commonly, ventricular tachycardia may also occur.
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37. Supportive Measures
1. Rest
2. Mild sedation
3. Fluid and electrolyte replacement
4. Nutritional support and vitamins as needed
5. Oxygen therapy
6. Nonspecific therapy as indicated
7. Antibiotics
8. Cardio-support as indicated
9. Cooling, aided by cooling blankets and acetaminophen
37
38. Specific therapy
1. Propranolol (20 to 200 mg orally every 6 hours, or 1 to 3 mg intravenously every 4 to 6 hours), Start with
low doses
2. Antithyroid drugs (PTU 500 –1000mg load, then 250mg every 4 hours
or Methimazole 60-80mg/day), then taper as condition improves
3. Potassium iodide (one hour after first dose of antithyroid drugs): 250mg orally every 6 hours
4. Dexamethasone 2 mg every 6 hours or hydrocortisone 300mg intravenous load, then 100mg every 8 hours.
38
39. Second Line Therapy
1. Sodium ipodate (ORAgrafin) or other iodinated contrast agents
2. Plasmapheresis
3. Oral T4 and T3 binding resins (Bile Acid Sequestrants) - colestipol or cholestyramine
4. Dialysis
5. Lithium in patients who cannot take iodine
6. Thyroid surgery
39
40. DRUGS USED IN THE TREATMENT OF THROID STORM
DRUG DOSING COMMENT
Propylthiouracil 500 – 1000 mg load then 250 mg
Every four hours
Blocks hormone synthesis.
Blocks T4 – to – T3 conversion
Methimazole
(Tapazole 5mg tab.)
Alternate drug : Carbimazole.
12 tabs po (Initial: 0.5-0.7 mg/kg/day
PO per day or divided /8hr ,
then 0.2-0.5 mg/kg/day PO ;
after Euthyroidism is achieved).
Blocks new hormone synthesis
Propranolol (Inderal)
60 – 80 mg po every four hours
(can be taken intravenously ,
3 mg every 4 hours) titrate with HR.
Consider invasive monitoring in congestive
heart failure patients.
Blocks T4 – to – T3 conversion in high doses.
Alternate drug : Esmolol (Brevibloc) infusion.
Iodine
(Saturated solution of potassium
iodide)
5 drops (250 mg) orally or through
NGT every 6 hours.
Lugol’s Iodine (10 mg iodine/drop):
25 drops PO/NGT every 6 hr.
Don’t start until one hour after antithyroid
drugs.
Blocks hormone synthesis and release.
Hydrocortisone
300 mg intravenous load then
100 mg every 8 hours
May Block T4 – to – T3 conversion.
Prophylaxis against relative adrenal insufficiency.
Alternate drug : Dexamethasone
0.1-0.2 mg/kg per day divided every 6-8 hours
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41. PTU NOTE by FDA
PTU is associated with the risk for severe fatal liver injury
and acute liver failure
PTU should be reserved for use in those who cannot tolerate other
treatments such as methimazole, radioactive iodine, or surgery.
PTU is now considered as a second-line drug therapy for treatment
of hyperthyroidism in general (though not thyroid storm) , except in
patients who are allergic or intolerant to methimazole, or women
who are in the first trimester of pregnancy.
US Food and Drug Administration. FDA MedWatch Safety Alerts for Human Medical Products.
Propylthiouracil (PTU). Available at http://bit.ly/s0sNi.Accessed: June 3, 2009.
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42. Bile acid sequestarnts
Prevent reabsorption of free THs in the gut (released from conjugated TH
metabolites secreted into bile through the enterohepatic circulation).
A recommended dose is 4 g of cholestyramine every 6 hours
via a nasogastric tube. Another option is 20-30 g/day of Colestipol-HCl.
De Groot LJ, Bartalena L, De Groot LJ, Chrousos G, Dungan K, Feingold KR, et al. Thyroid Storm. In: De
Groot LJ, Beck-Peccoz P, Chrousos G, Dungan K, Grossman A, Hershman JM, Koch C, McLachlan R, New M,
Rebar R, Singer F, Vinik A, Weickert MO, editors. SourceEndotext [Internet]. South Dartmouth (MA):
MDText.com, Inc. 2000.
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43. Management of thyroid storm
IV Fluids (Volume resuscitation) : Dextrose solutions are the preferred intravenous fluids
to cope with continuously high metabolic demand.
Use Digoxin for heart failure especially in the presence of
atrial fibrillation with rapid ventricular response.
Aggressive management of high fever with Paracetamol and Cooling blankets ,
ice packs and Pethidine 25 – 50 mg iv/6 hours to prevent/treat shivering.
Multi - organ supportive measures.
Treatment of the underlying condition and accompanying infection.
Monitoring in ICU.
43
44. Adequate therapy should resolve the crisis within a week.
$$ The following factors were associated with increased
mortality risk in thyroid storm :
1.Age 60 years or older
2.Central nervous system (CNS) dysfunction at admission
3.Lack of antithyroid drug and beta-blockade use
4.Need for mechanical ventilation and plasma exchange
along with hemodialysis
Ono Y, Ono S, Yasunaga H, Matsui H, Fushimi K, Tanaka Y. Factors Associated
With Mortality of Thyroid Storm: Analysis Using a National Inpatient Database in
Japan. Medicine (Baltimore). 2016 Feb. 95 (7):e2848
44
46. Conclusion
Thyroid storm is a severe form of hyperthyroidism with high mortality and
serious sequelae.
This condition is characterized by multiple organ failure, decompensation
and death. Therefore, although it is rare, thyroid storm requires prompt
diagnosis and multidisciplinary intensive medical care.
ICU admission should be recommended for all thyroid storm patients; patients
with potentially fatal conditions such as shock, disseminated intravascular
coagulation (DIC) and multiple organ failure should immediately be admitted
to the ICU .
46
47. Conclusion
Treatment of thyroid storm includes beta adrenergic blockers
and corticosteroids. The traditional beta blocker is propranolol
(Inderal) selected because it blocks peripheral conversion of
T4 to T3 and has protective cardiovascular effects.
Dosages : up to120mg po or 3mg IV every 4 hours.
Other beta blockers have been used.
Corticosteroids are recommended to treat the relative
adrenal insufficiency that results from accelerated metabolism and
improve vasomotor symptoms.
47
48. Conclusion
Antithyroid treatment should be continued until Euthyroidism
is achieved, when a decision
regarding definitive treatment of the hyperthyroidism
with antithyroid drugs, surgery or 131-I therapy
can be made.
Rarely urgent thyroidectomy is performed with
antithyroid drugs, iodide and beta blocker preparation.
48
49. Conclusion
Glucocorticoids should be weaned and stopped and
Beta-blockers may be discontinued once thyroid
function normalizes.
If the patient is given PTU during treatment of
thyroid storm, this should be switched to
methimazole at the time of discharge.
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52. Levothyroxine(Eltroxin)picksandtricks
Patients be started and maintained on either brand-name
or generic levothyroxine preparations, and not switched back
and forth between the two.
Patients who do switch products should undergo repeat TSH
and free T4 testing in six weeks to ensure normal range levels.
Thyroid hormone is generally taken in the morning, 30 minutes
before eating. Calcium , iron supplements and Soya should not be taken
within four hours of taking levothyroxine, because these supplements may
decrease thyroid hormone absorption.
The starting dosage of levothyroxine in young, healthy adults for
complete replacement is 1.6 mcg per kg per day.
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53. References
Endocrine emergencies in anesthesia.
Claudia Fernandez-Robles, Zyad J. Carr, and Adriana D. Oprea
Current opinion in anesthesiology, Volume 34 , Number 3 , June 2021.
ENDOCRINE EMERGENCIES
WILLIAM R. FURMAN, M.D.
The ASA Refresher Courses in Anesthesiology, vol.37 , chapter 5, 2009.
Anesthesia and the Patient with Thyroid, Parathyroid, or Adrenal Disease
William R. Furman, M.D.
Anesthesiology refresher course lectures 2011, 434.
ANAESTHESIA FOR THYROID SURGERY.
ANAESTHESIA TUTORIAL OF THE WEEK 162, 30TH NOVEMBER 2009
Lucy Adams & Sarah Davies.
Medscape : Thyroid Storm practice essentials, pathophysiology,
etiology …… (Updated: Mar 16, 2020).
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