- Approaching the diagnosis
- Diagnostic criteria
- Refractory thyroid storm
- Questions & discussion
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approaching the diagnosis
Thyroid storm is the most severe form of hyperthyroidism, wherein organ failure begins to occur. If left untreated, this may lead to multi-organ failure and death. Due to the rarity of this condition and its multitude of diverse presentations, diagnosis can be extremely challenging.
when to consider thyroid storm
- Thyroid storm is very rare, so the main challenge is considering it. The possibility should be entertained in the following situations:
- (1) Patient with known hyperthyroidism plus any acute illness/deterioration.
- (2) New-onset atrial fibrillation and/or dilated cardiomyopathy.
- (3) New-onset delirium/psychosis plus abnormal vital signs (fever, tachycardia).
- (4) Hyperthermia (temperature above ~40C).
- (5) Septic-appearing patient without any focus of infection (i.e. distributive shock of unknown origin).
precipitants of thyroid storm
- General stressors
- #1 = Infection
- Surgery or trauma (especially trauma involving the neck, such as strangulation)
- Pulmonary embolism, myocardial infarction, stroke
- Labor, preeclampsia
- Diabetic ketoacidosis, hypoglycemia
- Thyroid surgery, radioiodine therapy
- Noncompliance with anti-thyroid medications
- Overdose of thyroid hormone
- Acute iodine load from contrast dye or amiodarone
- Checkpoint inhibitors, Sorafenib (NEXAVAR, agent used for renal cell carcinoma)
- ~30% of patients have no identifiable precipitant.1
signs & symptoms
- Cardiac (often predominant feature)
- Tachycardia, atrial fibrillation
- High-output, distributive heart failure state
- Systolic heart failure can occur
- Delirium, agitation, psychosis
- Hyperthermia is nearly universal
- May reach 40-41C (104-106F), classically with associated diaphoresis
- Diarrhea, nausea, vomiting
- Abdominal pain
- Jaundice, hepatic failure
- Other features may suggest hyperthyroidism
- Goiter, scar from partial thyroidectomy
- Thyroid labs aren't worse than uncomplicated hyperthyroidism. The differentiation between hyperthyroidism and thyroid storm is based on clinical findings – not how severe the lab abnormality is.
- Key findings: Low TSH & elevated free T4 and free T3
- May also see:
- Low or high WBC
- Abnormal liver function tests
— Dustin Morrow MD (@SonoSerious) December 20, 2015
Burch criteria for thyroid storm
- 37.2-37.7 (99-99.9) = 5 points
- 37.8-38.2 (100-100.9) = 10 points
- 38.3-38.8 (101-101.9) = 15 points
- 38.9-39.4 (102-102.9) = 20 points
- 39.5-39.9 (103-103.9) = 25 points
- 40+ (104+) = 30 points
- 99-109 = 5 points
- 110-119 = 10 points
- 120-129 = 15 points
- 130-139 = 20 points
- >140 = 25 points
- CNS effects
- Mild (e.g. agitation) = 10 points
- Moderate (e.g. delirium, psychosis) = 20 points
- Severe (e.g. seizure, coma) = 30 points
- Diarrhea, n/v, abdominal pain = 10 points
- Unexplained jaundice = 20 points
- Heart failure
- Mild (e.g. edema) = 5 points
- Moderate (e.g. rales) = 10 points
- Severe (e.g. pulmonary edema) = 15 points
- Atrial fibrillation present = 10 points
- Precipitant history present = 10 points
interpretation of Burch criteria
- 45 or more: Highly suggestive of thyroid storm
- 25-44: Supports diagnosis of thyroid storm or impending storm
- <25: Thyroid storm unlikely
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- Thyroid storm is difficult to diagnose because there is a continuum of severity, ranging from severe hyperthyroidism to thyroid storm. Any specific binary cutoff is artificial.
- These diagnostic criteria are helpful because they provide a systematic framework to think about the diagnosis. However, we aren't forced to adhere rigidly to these criteria, for a few reasons:
- 1) The diagnosis of thyroid storm is a partially a diagnosis of exclusion. For example, sepsis with multi-organ failure could easily score >45 points on the above criteria. Therefore, a score >45 doesn't prove a diagnosis of thyroid storm.
- 2) Treatment for thyroid storm is reasonable in any patient with severe hyperthyroidism causing organ failure (especially heart failure). Therefore, even if the patient doesn't have a score >45, it may be prudent to initiate therapy for thyroid storm. Patients with borderline storm may improve rapidly and then therapy can be de-escalated.
getting started: evaluation & tx of cause
Evaluation includes securing a diagnosis of thyroid storm and simultaneously looking for any potential trigger of the episode. Consider the list of common precipitants above.
basic studies to order
- Glucose, electrolytes including Ca/Mg/Phos
- Liver function tests
- Coagulation studies (can cause DIC)
- Creatinine kinase (can cause rhabdomyolysis)
if infection is suspected
- Blood cultures & infectious workup as indicated.
- There should generally be a low threshold for initiation of antibiotics (e.g. if the patient has vasodilatory shock, or focal signs of infection). If antibiotics are being started, check procalcitonin.
- Steroid blocks release of T4 from the thyroid and also blocks peripheral activation of T4 into T3.
- The loading dose of hydrocortisone is 300 mg IV.
- The maintenance dose of hydrocortisone 100 mg IV Q8hr.
- If hydrocortisone isn't immediately available, may use methylprednisolone 60 mg.
- Thionamides block thyroid hormone synthesis. This is generally a cornerstone of therapy, although it may be ineffective in rare cases of thyroid storm due to thyroiditis.2
- Methimazole [Medscape monograph]
- The safest thionamide (less hepatotoxic).
- Clinical evidence suggests that it may be equally effective as propylthiouracil.
- May be the preferred agent, especially in patients with hepatitis.
- Methimazole dose is 40 mg loading dose, then 20 mg q4 hours.
- Propylthiouracil [Medscape monograph]
- Theoretically more effective than methimazole, because it reduces peripheral conversion of T4 into T3.
- Propylthiouracil is more hepatotoxic, with an FDA black box warning for causing hepatic failure.
- Might be preferred in more fulminant and definite cases of thyroid storm, or in pregnancy.
- Dose is 200 mg propylthiouracil q4.
- Transition to methimazole once patient is improving clinically.
- Immediately suppresses thyroid hormone release via the Wolff-Chiakoff effect.
- Must be given at least an hour after thionamide (to prevent increasing thyroid hormone synthesis).
- Different hospitals have different formulations:
- Lugol's Solution 8 drops PO q6hr (take with fluid/food to avoid gastritis).
- Saturated solution of KI (SSKI), 5 drops PO q6hr.
- For patients allergic to iodide, lithium may be used instead (300 mg PO q6-8hr, target lithium level of 0.6-1 mEq/L).
- This binds thyroid hormone in the gut and prevents enterohepatic re-absorption.3
- Effective even in patients who haven't taken exogenous thyroid hormone (e.g. Graves disease).
- Extremely safe (available over-the-counter for treatment of diarrhea).
- Dose is 4 grams orally q6hrs.
- Continue until patient is clinically improved.
thyroid storm may cause numerous hemodynamic derangements:
- 1) Hypovolemia (from diaphoresis, vomiting, diarrhea)
- 2) Systolic heart failure, including cardiogenic shock
- 3) Distributive shock (increased tissue oxygenation causes systemic vasodilation)
- 4) Tachycardia (either sinus tachycardia or atrial fibrillation).
- Moderate tachycardia may be a compensatory response to shock, which improves cardiac output.
- Severe tachycardia may be pathological, reducing ventricular filling and thereby exacerbating cardiovascular dysfunction.
Recent onset dyspnoea. This is the ECG. Bedside echo showed EF 30%. The cause- recent onset thyrotoxicosis pic.twitter.com/YFGFLzKZBa
— Victoria Stephen (@EMcardiac) April 2, 2014
- Volume should be repleted based on echocardiography, lung sonography, and history (e.g. history of poor oral intake, fever, and diarrhea suggest volume depletion).
- Vasopressors may be needed to maintain an adequate blood pressure. If the patient is already very tachycardic, phenylephrine might be a reasonable consideration to avoid exacerbating tachycardia.
- Magnesium repletion is a good first step for patients with atrial fibrillation and rapid ventricular rate. Hyperthyroidism itself may cause hypomagnesemia.
be careful about beta-blockers
- Widely recommended for thyroid storm, but be very careful: beta-blockade may exacerbate shock (especially in patients with systolic heart failure). A moderate degree of compensatory tachycardia (e.g. heart rate 110-130 b/m) may be necessary to maintain adequate perfusion in some patients.
- Tachycardia is not the primary problem here. Aggressive beta-blockade may cause more harm than benefit.
- The literature contains numerous reports of patients who crash within 6 hours of initiation of therapy for thyroid storm. In many of these cases, beta-blockade may be the cause of deterioration.4
- Don't blindly give beta-blockers without first performing a complete hemodynamic evaluation (echocardiogram plus lung ultrasonography to look for evidence of cardiogenic pulmonary edema).
- More on hemodynamic evaluation in heart failure here.
- Contraindications to beta-blockade:
- Shock (especially cardiogenic shock with severely reduced ejection fraction)
- Cardiogenic pulmonary edema
- Esmolol infusion is probably the safest initial agent [Medscape monograph on esmolol]
- Up-titrate to ensure that the patient can tolerate beta-blockade.
- Japanese guidelines recommend esmolol, due to increased mortality in patients with heart failure treated with propranolol.5
- Propranolol [Medscape monograph on propranolol]
- Ideal beta-blocker, because it blocks peripheral activation of T4 to T3.
- Starting dose is 20-40 mg PO q6hr. If tolerated, may up-titrate to a dose of 80 mg q6.
— Scott K Aberegg MD MPH (@medevidenceblog) February 8, 2019
management of hyperthermia & agitation
- General principles:
- Hyperthermia is harmful because it increases cardiac workload and can also cause organ damage (e.g. rhabdomyolysis, delirium).
- However, induction of shivering is potentially dangerous, as this also increases myocardial workload. Fortunately, hyperthermia is due to increased heat generation by the tissues (rather than a change in hypothalamic set point), so shivering may not be a problem in these patients.
- Acetaminophen 650-1000 mg q6hr scheduled.
- Use of cooling blankets is recommended for high fever, if tolerated without shivering.1,5
- Avoid salicylates or NSAIDs, since these may increase free thyroid hormone levels.
- Agitation may worsen hyperthermia and impede ability to provide care.
- Olanzapine might be a good choice, either by PO, IM, or IV routes.5
- Case studies exist suggesting that haloperidol may precipitate thyroid storm. Although this is dubious, it might be a reason to prefer olanzapine over haloperidol.5
refractory thyroid storm
- Clinical improvement should ideally be seen reasonably soon (e.g. ~24-48 hours).
- Some patients will fail to respond to optimal medical management.
- Treatment options for refractory thyroid storm include plasmapheresis or thyroidectomy.
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questions & discussion
To keep this page small and fast, questions & discussion about this post can be found on another page here.
- Maintain a high index of suspicion for thyroid storm, as this will commonly mimic other conditions (e.g. psychosis, meningitis, hyperthermia, sepsis, cardiogenic shock).
- Avoid salicylates or NSAIDs, as these may bind to thyroid-binding globulin, causing increased levels of free thyroid hormone levels.
- Be cautious with beta-blockers, because some patients have thyrotoxicosis-induced cardiomyopathy and distributive shock. Aggressive beta-blockade may cause hemodynamic collapse in this situation, because the tachycardia is a compensatory response.
5-minute video to review everything (by Anna Pickens)
- Thyroid storm (EMCrit podcast 149)
- Thyroid storm (Nadia Award, ALIEM)
- Thyroid storm (Justin Morgenstern, First 10 in EM)
- Thyroid storm (Anand Swaminathan, CoreEM)
- Thyroid storm (Chris Nickson, LITFL)
- Thyroid storm (WikEM)
- Methimazole vs PTU (Jeff Hall & David Slattery, Vegas EM)
- 2016 Japan guidelines for thyroid storm (Satoh et al).
- Thyroid ultrasonography in Graves disease