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Thyroid Storm — Thionamides, Iodine Timing, β-Blockade, and Steroids

System: Endocrinology • Reviewed: Sep 2, 2025 • Step 1Step 2Step 3

Synopsis:

Severe thyrotoxicosis with multiorgan dysfunction. Start β-blockade; give PTU 500–1000 mg load then 250 mg q4h (or Methimazole 20 mg q4–6h), followed by iodine (SSKI) 1–2 h later to block release. Add hydrocortisone 100 mg IV q8h and supportive care including cooling and fluids.

Key Points

  • Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
  • Set objective targets and reassess frequently.
  • Plan definitive source control or disease‑specific therapy when indicated; document follow‑up and patient education.

Algorithm

  1. Start β-blocker; administer thionamide; after 1–2 h give iodine; add hydrocortisone.
  2. Treat precipitant; aggressive supportive care (cooling, fluids, nutrition).
  3. Titrate therapy to clinical response; transition to maintenance and plan for definitive therapy.

Clinical Synopsis & Reasoning

Severe thyrotoxicosis with multiorgan dysfunction. Start β-blockade; give PTU 500–1000 mg load then 250 mg q4h (or Methimazole 20 mg q4–6h), followed by iodine (SSKI) 1–2 h later to block release. Add hydrocortisone 100 mg IV q8h and supportive care including cooling and fluids.


Treatment Strategy & Disposition

Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced/procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.


Epidemiology / Risk Factors

  • Risk varies by comorbidity and precipitants; see citations for condition‑specific data.

Investigations

TestRole / RationaleTypical FindingsNotes
Burch–Wartofsky score (or Japanese Thyroid Association)SeverityQuantify likelihood
TSH/free T4/T3 (do not delay)DiagnosisThyrotoxicosis pattern
Infection, MI, PE workupTriggersCommon precipitantsTreat source

High-Risk & Disposition Triggers

TriggerWhy it mattersAction
Atrial fibrillation with instability or heart failureHigh mortalityICU; esmolol infusion
Hyperthermia >40°CMultiorgan failure riskActive cooling
Sepsis or precipitating surgeryWorsening triggerAggressive source control
PregnancyDrug selection nuanceSpecialist input on thionamide choice
Hepatic failurePTU riskPrefer methimazole; monitor LFTs

Pharmacology

Medication/InterventionMechanismOnsetRole in TherapyLimitations
Propranolol 20–80 mg PO q6h (or Esmolol infusion)β-blockadeMinutesSymptom and rate controlWatch for HF/asthma
PTU 500–1000 mg load then 250 mg q4h (or Methimazole 20 mg q4–6h)Block synthesis/5'-deiodinase (PTU)HoursCore therapyHepatotoxicity (PTU)
SSKI 5 drops PO q6h (or Lugol) started 1–2 h after thionamideIodine blockadeHoursInhibits releaseTiming crucial
Hydrocortisone 100 mg IV q8hAdrenal support/T4→T3 blockHoursStress dosing
Cholestyramine 4 g PO QID (adjunct)Peripheral clearanceDaysSevere cases

Prognosis / Complications

  • Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.

Patient Education / Counseling

  • Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.

References

  1. ATA hyperthyroidism/thyroid storm guidance — Link

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