Thyroid Storm

OVERVIEW

• life threatening exacerbation of hyperthyroid state with 1 or more organ dysfunction
• clinical diagnosis, very elevated thyroid markers not enough

ETIOLOGY

Hyperthyroidism due to:

• Graves Disease – most common
• Toxic Nodule or Toxic Multinodular Goitre
• Thyroiditis (infective or auto-immune)

Triggers for thyroid storm:

• Surgery (thyroid and non-thyroid) –> can occur 6 – 24 hours post op
• Discontinuation of anti-thyroid medication
• Trauma
• Burns
• Hyperemesis Gravidarum
• Parturition
• Acute illness
  • Infective
  • Non-infective: DKA, MI, CVA, TBI
• Iodine Use (iodinated contrast or radioiodine therapy)
• Medication Reactions (amiodarone, anaesthetics, salicylates)

CLINICAL FEATURES

General

• Fever
• Diaphoresis

Cardiovascular

• Tachycardia (sinus tachycardia is most common)/Tachyarrhythmia (AF with RVR most common tachyarrhythmia)
• Signs of cardiac failure (peripheral/pulmonary oedema)

Neurological

• CNS dysfunction of varying severity (agitation –> psychosis –> seizure –> coma)

Gastrointestinal

• diarrhoea/nausea/vomiting
• unexplained jaundice

DIAGNOSTIC SCORES

• Quantitative diagnostic scoring systems are used as adjunct to clinical assessment
  • e.g elderly patients may present with “apathetic” thyroitoxicosis with atypical symptoms
• May help differentiate uncomplicated thyrotoxicosis from thyroid storm

Burch-Wartofsky Point Scale (introduced in 1993)

• Use in adults with biochemical evidence of thyrotoxicosis
• Interpretation:
  • A score of 45 or more is highly suggestive of thyroid storm.
  • A score of 25 – 44 suggests “impending” thyroid storm

Japanese Thyroid Association (JTA)/Japanese Endocrine Society (JES) Score

• Pre-requisite: Biochemical thyrotoxicosis (elevated FT3 and/or FT4)

• Interpretation:
  • TS1 (Definite Thyroid Storm):
    • Thyrotoxicosis + CNS manifestations + ≥1 of: fever, tachycardia, CHF, or Gl/hepatic manifestations
      OR
      Thyrotoxicosis + any 3 of: fever, tachycardia, CHF, or Gl/hepatic manifestations
  • TS2 (Suspected Thyroid Storm):
    • Thyrotoxicosis + any 2 of: fever, tachycardia, CHF, or Gl/hepatic manifestations

MANAGEMENT

Supportive

• IVF (glucose)
• cooling cares
• paracetamol (no NSAIDs or aspirin -> displaces thyroxine from proteins)
• propanolol increments (1mg IV) or esmolol boluses -> infusion (50-100mcg/kg/min)

Specific

• hydrocortisone 200mg IV QID (adrenal insufficiency + decreases T4 release and conversion)
• propylthiouracil (1g load PO -> 250mg QID to inhibit thyroid hormone release and decrease peripheral conversion from T4-T3)
• after blockade by propylthiouracil give sodium iodide or potassium iodide or Lugol’s iodine

References and Links

Journal articles

• Bello G, Ceaichisciuc I, Silva S, Antonelli M. The role of thyroid dysfunction in the critically ill: a review of the literature. Minerva Anestesiol. 2010 Nov;76(11):919-28. PMID: 20935602.
• Carroll R, Matfin G. Endocrine and metabolic emergencies: thyroid storm. Ther Adv Endocrinol Metab. 2010 Jun;1(3):139-45. PMC3475282.
• Muller C, Perrin P, Faller B, Richter S, Chantrel F. Role of plasma exchange in the thyroid storm. Ther Apher Dial. 2011 Dec;15(6):522-31. PMID: 22107688.

FOAM and web resources

• ALIEM — Diagnosing hyperthyroidism: Answers to 7 common questions  (2013)
• ALIEM — Thyroid Storm: Treatment Strategies (2013)