Thyroid Storm

Aka: Thyroid Storm, Thyroid Crisis

1. See Also
   1. Hyperthyroidism
2. Definitions
   1. Thyroid Storm
      1. Severe Thyrotoxicosis
3. Causes
   1. Uncontrolled Hyperthyroidism (esp. Graves Disease) with concurrent acute stress
      1. Pulmonary Infection (most common cause)
      2. Myocardial Infarction
      3. Trauma
   2. Other, uncommon causes
      1. Graves Disease following Radioactive Iodine therapy
4. Precautions
   1. Elderly may present with minimal signs of Thyrotoxicosis (apathetic Thyroid Storm) with CHF, stupor to coma
5. Symptoms
   1. See Hyperthyroidism
6. Signs
   1. Fever >39 C (102 F)
   2. Sinus Tachycardia
   3. Profuse sweating
   4. High output cardiac failure
   5. Tachyarrhythmias (esp. Atrial Fibrillation)
   6. Altered Level of Consciousness (Delirium or Psychosis)
7. Differential Diagnosis
   1. Sepsis
   2. Sympathomimetic Toxicity (Stimulant Overdose)
   3. Alcohol Withdrawal
   4. Malignant Hyperthermia
   5. Neuroleptic Malignant Syndrome
   6. Heat Related Illness
8. Associated Conditions
   1. New onset Atrial Fibrillation
   2. New onset, unexplained Congestive Heart Failure
9. Labs
   1. Broad based lab evaluation to cover differential diagnosis
   2. Thyroid Stimulating Hormone (TSH)
      1. Suppressed in most cases
      2. Increased in TRH-Secreting Tumors (10-15% of Thyroid Storm cases)
   3. Free T4
      1. Increased
10. Diagnosis
    1. See Thryoid Storm Diagnosis (Burch Wartofsky Score)
11. Management
    1. General Measures
       1. Manage Airway
       2. Supplemental Oxygen
       3. Intravenous Fluids
       4. Cooling blanket and other external cooling
          1. Avoid active cooling due to worsening the Vasoconstriction already present with Thyroid Storm
       5. Use Acetaminophen for fever
       6. Avoid Salicylates and NSAIDS due to their increase of T4 and T3
          1. NSAIDS and Salicylates dislodge T4 from protein binding and allow for conversion to the more active T3
       7. Treat concurrent infection (often inciting event)
    2. Step 1: Heart Rate control (Beta Blockers are preferred)
       1. Beta Blockers (preferred)
          1. Beta Blockers slow rate AND decrease peripheral conversion from T4 to the more active T3
          2. Propranolol 10-20 mg IV every 4 hours (or 60 to 80 mg every 4 hours)
          3. Metoprolol 5-10 mg IV every 2-4 hours (or Metoprolol Tartrate 50 mg every 6 hours)
          4. Esmolol 50-100 mcg/kg/min IV
       2. Diltiazem (if Beta Blockers are contraindicated)
          1. Calcium Channel Blockers do not decrease peripheral conversion from T4 to the more active T3
          2. Diltiazem 0.25 mg/kg IV bolus over 2 min, then 10 mg/h IV (or 60-90 mg orally every 6-8 hours)
    3. Step 2: T4 and T3 Synthesis suppression with Thionamides
       1. Methimazole 20-40 mg every 8 hours IV, PO, PR, per NG
          1. Methimazole is preferred in second and third trimesters of pregnancy
       2. Propylthiouracil (PTU) 200-400 mg every 8 hours PO, PR, per NG
          1. Propylthiouracil is preferred in first trimester of pregnancy
    4. Step 3: T4 and T3 Release suppression
       1. Do NOT give before synthesis suppression (see step 2)
          1. May otherwise promote new Thyroid hormone synthesis
       2. Saturated Solution Potassium iodide (SSKI)
          1. Dose: 5 drops mixed in fluid or food every 6 hours for at least 2 days
          2. Initiate at least one hour after antithyroid medication
    5. Step 4: T4 to T3 conversion suppression with Glucocorticoids
       1. Hydrocortisone 100 mg IV every 8 hours
          1. Also counters autoimmune process in Graves
          2. Manages concurrent Adrenal Insufficiency
12. Complications
    1. Atrial Fibrillation
    2. Congestive Heart Failure
       1. Critical to distinguish between high output Heart Failure and low output Heart Failure
       2. Bedside Ultrasound
          1. Hyperdynamic heart activity is more consistent with high output Heart Failure
13. References
    1. Swaminathan and Willis in Herbert (2019) EM:Rap 19(10): 13-5
    2. Carroll (2010) Ther Adv Endocrinol Metab 1(3): 139–145 [PubMed]
       1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3475282/
    3. Kravets (2016) Am Fam Physician 93(5): 363-70 [PubMed]
    4. Nayak (2006) Endocrinol Metab Clin North Am 35(4): 663-6 [PubMed]