Thyroid storm

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Background

  • Mortality
    • Without treatment: 80-100%
    • With treatment: 15-50%

Precipitants

  • Infection
  • Trauma
  • Recent thyroid manipulation (physical or surgical)
  • Burns
  • Surgery
  • DKA
  • Withdrawal of thyroid medication
  • Iodine administration
  • MI
  • CVA
  • PE
  • Interferon treatment
  • Molar Pregnancy
  • Hypoglycemia
  • Withdrawl of antithyroid treatment
  • Exposure to iodine (or iodinated contrast)

Clinical Presentation

Classic Triad

Differential Diagnosis

Diagnosis

Work-Up

  • Chemistry (Cr may be low or High Ca)
  • CBC (may have Thrombocytopenia)
  • TSH/Free T3/T4
  • Cortisol level (rule-out concurrent adrenal insufficiency)
  • ECG
  • Rule-out infection:

Burch & Wartofsky Diagnostic Criteria

Category Points
Thermoregulatory dysfunction (°F)
Tmax= 99-99.9 5
Tmax= 100-100.9 10
Tmax= 101-101.9 15
Tmax= 102-102.9 20
Tmax= 103-103.9 25
Tmax= 104 30
Central nervous system effects
Mild (Agitation) 10
Moderate (delirium, psychosis, extreme lethargy) 20
Severe (seizure, coma) 30
Gastrointestinal-hepatic dysfunction
Moderate (diarrhea, n/v, abd pain) 10
Severe (unexplained jaundice) 20
Cardiovascular dysfunction (tachycardia)
HR= 99-109 5
HR= 110-119 10
HR= 120-129 15
HR= 130-139 20
HR= 140 25
Congestive Heart Failure
Mild (pedal edema) 5
Moderate (bibasilar rales) 10
Severe (pulm edema, A. fib) 15
Precipitant history
Negative 0
Positive 10

Scoring[1]

  • >45 = Highly suggestive of thyroid storm
  • 25-44 = Suggestive of impending storm
  • <25 = Unlikely to represent storm

Treatment[2]

Identify precipitant (i.e. med noncompliance, DKA, infection)

Supportive care

  1. Fever
    • Cooling measures (ice packs & cooling blankets)
    • Acetaminophen (avoid aspirin or NSAIDS because they displace thyroid hormone from TBG)
  2. Dehydration/hypoglycemia
    • D5NS (most pts have depleted glycogen stores)
  3. Cardiac decompensation (CHF, A-fib)
    • Rate control, inotropes, diuretics as needed (short acting always better)
  4. Agitation
    • Benzodiazepines are the preferred agent

Decrease Peripheral Hormone Conversion

can use PO or IV Propranolol

  1. Propranolol PO 60-80 q4hr (if pt can tolerate PO)
  2. Propranolol IV 1-2mg over 10 min; if tolerates then 1-2mg boluses q15 minutes until HR <100
    • followed by drip at dose required for heart rate control (3-5mg/hr)
    • Relative contraindications are same as for other medical conditions (e.g. CHF, Reactive Airway Disease, see alternative therapies)
    • In addition to decreasing peripheral conversion there are propranolol will improve tremor, hyperpyrexia, and agitation

Block New Hormone Synthesis

Thionamides are the main class of medications which prevent new hormone synthesis by inhibiting the iodination of tyrosine residues by thyroid peroxidase (TPO) enzymes. Propylthiouracil (PTU) is prefered over methimazole because it will also bock T4->T3 conversion

  1. PTU 600-1000 mg PO or PR followed by 200-250mg q4hr
    • Note black box warning of hepatotoxicity so check LFTs prior
    • Avoid in patients with significant liver disease; use methimazole instead
  2. Methimazole 20-25mg q4hr
    • Longer acting than PTU
    • Should be avoided in pregnancy by classic teaching (Freely crosses placenta, birth defects)
  3. Potassium iodide (SSKI)
    • Give 1hr after PTU to prevent increased hormone production (Jod-Basedow effect)[3]
    • Block hormone release: (Wolff-Chaikoff effect) only after hormone synthesis is inhibited. Iodine concentration leads to transient decrease of T3/T4
    • 5 drops (0.25 mL or 250 mg) orally every 6 hours
    • Avoid potassium iodide if patient is on amiodarone
    • Can substitute radiocontrast dyes (Iopanoic acid, ipodate and iopanoate) or oral lugol solution
  4. Lithium carbonate[4]
    • 300mg q6hr
    • Consider if iodine allergic
    • Lithium carbonate 300mg PO q8hr
    • Lithium inhibits thyroid hormone release from the gland and reduces iodination of tyrosine residues, but its use is complicated by the toxicity that can ensue.
  5. Lugol’s Solution 8 drops PO q 6 (alternative iodine source)
  6. Sodium Iodide 0.5 mg IV Q 12 hours (alternative iodine source)

Other Therapies

  1. Esmolol 250-500mcg/kg loading dose, then 50-100mcg/kg/min
    • B1 selective so can be used in pt with active CHF, asthma, etc. but it does not perform any of the other benefits of propranolol.
  2. Treatment of sympathetic Surge
    • Propranolol
  3. Hyperthermia
    • Aggressive cooling should be avoided due to the possibility of worsening vasoconstriction [3]

Adrenal Insufficiency Treatment

Often there may be associated adrenal insufficiency (also blocks T4>T3)

Disposition

  • Admission to ICU

See Also

Sources

  1. ↑ Burch HB, Wartofsky L. Life-threatening thyrotoxicosis. Thyroid storm. Endocrinol Metab Clin North Am. 1993 Jun;22(2):263-77
  2. ↑ American Thyroid Association Treatment Recomendations http://www.thyroid.org/thyroid-guidelines/hyperthyroidism/resultsh/
  3. ↑ 3.0 3.1 Chiha M. et al Thyroid storm: an updated review. J Intensive Care Med. 2015 Mar;30(3):131-40.
  4. ↑ Carroll R, Matfin G. Endocrine and metabolic emergencies: thyroid storm. Ther Adv Endocrinol Metab. 2010 Jun; 1(3): 139–145. Full Text
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