Hyperthyroidism / Thyroid storm
Considerations
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Potential difficult airway if goitre present (airway compression, anterior mediastinal mass)
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End organ effects of chronic hyperthyroidism:
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Hypermetabolic state (↑ VO2, VCO2)
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Cardiovascular: hypertension, tachycardia, myocardial ischemia, cardiomyopathy, arrhythmias
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CNS: anxiety, psychiatric disorders
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Muscle weakness
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Risk of thyroid storm
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Interactions with anesthetics:
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↑ anesthetic requirements to control BP & HR. MAC requirement is NOT increased
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Avoid sympathetic stimulants (ketamine, cocaine, epinephrine, etc)
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Thyroidectomy:
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Shared airway
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Airway obstruction (tracheomalacia, recurrent laryngeal nerve injury, neck hematoma, hypocalcemia)
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Optimization
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Optimize thyroid function & limit end organ effects: heart rate <90, normal TSH
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Identify difficult airway or anterior mediastinal mass
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Identify & manage thyroid storm
Conflicts
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Difficult airway/hemodynamic instability & sympathetic stimulants (cocaine, epinephrine, glycopyrrolate)
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Hemodynamic instability & RSI
Thyroid storm
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Emergency situation (mortality= 20%), consider endocrinology consult
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IV fluids
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Cool (blankets, IV solution, acetaminophen)
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Control hemodynamics:
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Esmolol 0.25-0.5 mg/kg bolus or 50-200 mcg/kg/min infusion
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Propranolol 10-40 mg PO or up to 1 mg/min IV
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Stop conversion of T4 to T3:
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PTU 200-400 mg PO/NG/PR q6h
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Hydrocortisone 100-200 mg IV q8h
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Stop synthesis & release of new hormone:
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Potassium iodide 5 gtts PO/NG q6h or sodium iodide 0.25 g IV q6h (1 hr after PTU)
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Look for & treat complications:
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CVA, loss of consciousness
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Myocardial infarction, atrial fibrillation (avoid amiodarone because of iodide content; use digoxin instead) or congestive heart failure
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Hypoventilation & hypercarbia
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Electrolyte abnormalities
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Consider differential diagnosis for hypermetabolic state
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Consider last ditch treatments: plasmapheresis, dantrolene, lithium, neuraxial blockade to T4