• Early recognition essential in initiating disease-specific life-saving treatments for this high mortality condition
• Thyroid storm can mimic other conditions (ex. psychosis, meningitis, hyperthermia, sepsis, cardiogenic shock) and should be considered in all patients with fever, altered mental status and signs of sympathetic over-activity.
• A low threshold to draw thyroid labs is essential in early diagnosis and treatment initiation.

• Thyroid storm is a rare, life-threatening condition characterized by severe/life-threatening manifestations of thyrotoxicosis
  • Often inappropriately applied to un/undertreated hyperthyroidism but clinically differentiated by severity of symptoms/life threat
• Usually precipitated by acute event, though can result from longstanding untreated hyperthyroidism.
  • General stressors: infection, surgery, trauma, PE/MI/Stroke, labor, preeclampsia, DKA, hypoglycemia
  • Thyroid-related: thyroid surgery, radioiodine therapy, irregular use or discontinuation of thyroid or antithyroid drugs, acute iodine load (amiodarone, contrast dye), checkpoint inhibitors, ASA intoxication
  • 30% have no identifiable precipitant.
• Mortality is high – up to 10-50% with treatment and up to 100% without treatment.
• Treatment must be specifically targeted at the condition as general supportive resuscitation does not provide definitive management.

Diagnosis based upon presence of severe and life-threatening symptoms (fever, cardiovascular dysfunction, altered mentation) in a patient with biochemical evidence of hyperthyroidism.

• Uncontrolled hyperthyroidism and thyroid storm exist on a continuum. Clinical judgement of severity required to make the thyroid storm diagnosis.

Diagnostic decision tools:

• Burch-wartofsky point scale
  • In patients with biochemical toxicosis, predicts likelihood of thyroid storm
  • Highly sensitive but poor specificity.
    • mildly uncontrolled hyperthyroid patient could screen positive in context of uncomplicated viral infection.

Symptoms and signs

• Patients tend to look very ill with prominent tremor, diaphoresis, mental status changes
  • Vitals: Tachycardia, hyperpyrexia
  • CVS: Sepsis mimic – fever + vasodilatory shock, CHF and associated symptoms, atrial fibrillation

CNS: Confusion, agitation, anxiety, delirium, psychosis, stupor, coma

• GI: Diarrhea, nausea, vomiting, abdominal pain, jaundice, hepatic failure
• Other features of hyperthyroidism (diaphoresis, tremor, goiter, exophthalmos, lid lag)

Labs:

• High T4 + T3, with low TSH
  • Absolute values not typically more profound than standard untreated hyperthyroidism.
• Evaluation of cause/precipitants + consequences
  • Glucose, electrolytes including Ca/Mg/Phos, LFTs, CBC, INR/PTT (to assess for DIC), CK (to assess for rhabdo), ECG
  • If infection suspected, blood cultures and infectious workup as indicated

• Thionamide: Blocks new hormone synthesis; either of:
  • Methimazole 20mg po q4-6h
    • Preferred (less hepatotoxic), although does have risk of agranulocytosis
  • Propylthiouracil (PTU) 200-250mg po q4h
• Iodine solution: Blocks the release of thyroid hormone
  • SSKI or Potassium Iodide and iodine (Lugol’s solution) one hour after first dose of thionamide (to prevent iodine usage as substate for thyroid hormone synthesis)
    • SSKI – 5 drops (50mg iodide/drop) po q6h
    • Lugol’s solution 10 drops (6.25mg iodide/iodine/drop) po q8h
  • Glucocorticoids: Reduces peripheral T4-to-T3 conversion, promotes vasomotor stability, possibly treats any associated adrenal insufficiency
    • Hydrocortisone 300mg IV loading dose, then 100mg IVq8h
  • Beta-Blocker: Carefully consider initiating a beta blocker to control the symptoms and signs
    • Propranolol 60-80mg po q4-6h or 0.5-1mg IV over 10 minutes followed by 1-2mg over 10 minutes q2-3h is preferred as it also blocks peripheral activation of T4 to T3
    • *beta-blocker may worsen cardiogenic or distributive shock*
      • Extreme caution is required, as beta blockers are contraindicated in patients with shock, or cardiogenic pulmonary edema
    • Bile acid sequestrants: May be of benefit in severe cases to decrease enterohepatic recycling of thyroid hormones
      • Cholestyramine 4g po q6h

Presentation specific treatments:

• Infection: reasonable to initiate empiric antibiotics in all febrile/hemodynamically unstable patients after blood cultures drawn before definitive diagnosis of thyroid storm made
• Hyperthermia: initiate acetaminophen 650-1000mg q6h scheduled. Consider cooling blankets, if tolerated without shivering (aggressive overcooling can lead to vasoconstriction)
• Agitation: can worsen hyperthermia or impeded ability to provide care. Consider olanzapine or midazolam PRN
• Atrial fibrillation: General supportive measures such as volume repletion, vasoactive agents as required.
  • Aggressive rate control may precipitate cardiogenic shock in patients with compensatory tachycardia.
• Find and treat precipitants

Other treatment considerations:

• Avoid NSAIDs and salicylates as they can increase levels of free T4 and T3.
• Careful discontinuation from treatments can take place in ICU setting when defervescence and resolution of cardiovascular/CNS manifestations.

Any patient with diagnosed thyroid storm should be admitted to an ICU, given life-threatening symptoms are necessary to make the diagnosis.

Patients with thyroid storm should be transferred to a facility with intensive care available. Transport should take place after initial treatments as described have been initiated.

1. Internet book of critical care: https://emcrit.org/ibcc/tstorm/#getting_started:_evaluation_&_tx_of_cause

    

   
   

1. Thiessen, M. (2018). Thyroid and Adrenal Disorders in Rosen’s emergency medicine: Concepts and clinical practice (9th ed.). Philadelphia, PA: Elsevier/Saunders.

   
   

2. Farkas, J. 2021. Thyroid Storm. Internet Book of Critical Care. Accessed from: http://emcrit.org/podcasts/thyroid-storm/

   
   

3. Chiha M. et al Thyroid storm: an updated review. J Intensive Care Med. 2015 Mar;30(3):131-40.

   
   

4. Ross,  D. 2022. UpToDate. UpToDate. Available from  https://www.uptodate.com/contents/thyroid-storm