📋 Key Information Summary
- Thyroid storm is a life-threatening endocrine emergency characterised by severe thyrotoxicosis with multi-organ dysfunction — mortality 10–30% even with treatment.
- Precipitants include infection, surgery/anaesthesia, trauma, radioiodine therapy, acute iodine load (CT contrast, amiodarone withdrawal), and abrupt antithyroid drug cessation.
- Diagnosis is clinical; the Burch–Wartofsky Point Scale (BWPS) ≥45 is highly suggestive (25–44 = impending storm).
- Core clinical features: fever ≥38.5°C, tachycardia disproportionate to fever, altered mental status (agitation, delirium, coma), GI dysfunction (diarrhoea, vomiting, jaundice), and heart failure.
- Management follows four pillars — block hormone synthesis (PTU preferred), block hormone release (Lugol's iodine ≥1 h after PTU), block peripheral T4→T3 conversion (dexamethasone, propranolol), and treat the precipitant.
- Propylthiouracil (PTU) 500 mg PO/NG loading then 250 mg every 4 h is first-line over carbimazole in storm because it also blocks peripheral T4→T3 conversion.
- Lugol's iodine (SSKI 5 drops TDS) or potassium iodide solution must be given ≥1 hour after the first dose of PTU to avoid fuelling new hormone synthesis.
- Propranolol 40–80 mg PO every 6 h (or 1–2 mg IV slow bolus) controls tachycardia and reduces peripheral T4→T3 conversion; avoid in severe heart failure or bronchospasm.
- Hydrocortisone 100 mg IV 6–8 hourly (or dexamethasone 2 mg IV 6-hourly) treats relative adrenal insufficiency and inhibits peripheral conversion.
- Active cooling with paracetamol + physical measures; avoid aspirin (displaces T4 from TBG, increasing free T4).
- Cholestyramine 4 g PO QDS reduces enterohepatic recirculation of thyroid hormones as adjunctive therapy.
- ICU admission is mandatory; liaise early with endocrinology and consider plasmapheresis or thyroidectomy as rescue in refractory cases.
- Aboriginal and Torres Strait Islander patients have higher Graves' disease prevalence; culturally safe care, interpreter services, and remote telehealth endocrinology input are essential.
🎧 Audio Brief
Introduction & Australian Epidemiology
Thyroid storm is a life-threatening exacerbation of thyrotoxicosis, representing the extreme end of the hyperthyroid spectrum. It is characterised by severe multi-organ decompensation — cardiovascular collapse, hyperthermia, altered consciousness, and hepatic/gastrointestinal dysfunction — and carries a mortality rate of 10–30% even with prompt, aggressive management.
In Australia, thyroid storm accounts for fewer than 2% of all thyrotoxicosis presentations but is disproportionately fatal. The most common underlying aetiology is Graves' disease, followed by toxic multinodular goitre and, less commonly, thyroiditis. The condition is triggered by an acute physiological stressor superimposed on existing (sometimes unrecognised) thyrotoxicosis.
Population-based data from the Australian Institute of Health and Welfare (AIHW) indicate that thyroid disorders affect approximately 1 in 10 Australians, with hyperthyroidism prevalence of 1.2–1.6%. Aboriginal and Torres Strait Islander populations have a higher burden of autoimmune thyroid disease, and remote-area patients face delayed recognition due to limited specialist access. Paediatric thyroid storm, although rare, has been reported in adolescent Graves' disease and carries a particularly high morbidity.
This guideline provides evidence-based recommendations for the recognition, scoring, investigation, and emergency management of thyroid storm in Australian clinical practice, aligned with Therapeutic Guidelines (eTG), the Australian Commission on Safety and Quality in Health Care (ACSQHC), and Endocrine Society of Australia (ESA) consensus statements.
Pathophysiology & Precipitants
Pathophysiology
Thyroid storm represents a state of extreme thyroid hormone excess combined with a heightened catecholamine response and systemic inflammatory activation. Several mechanisms converge:
- Excessive thyroid hormone: Markedly elevated free T4 (fT4) and free T3 (fT3) saturate nuclear thyroid hormone receptors in virtually every organ, increasing basal metabolic rate by up to 60–100%.
- Catecholamine hypersensitivity: Thyroid hormones upregulate β-adrenergic receptors, amplifying the haemodynamic effects of endogenous catecholamines — tachycardia, systolic hypertension with wide pulse pressure, and high-output cardiac failure.
- Thermogenic crisis: Uncoupled oxidative phosphorylation and increased Na⁺/K⁺-ATPase activity generate excessive heat, leading to hyperthermia that is often refractory to conventional antipyretics.
- Multi-organ dysfunction: Hepatic ischaemia causes conjugated hyperbilirubinaemia (jaundice); cerebral hyperperfusion and catecholamine excess cause delirium or coma; myocardial oxygen demand exceeds supply, precipitating heart failure or arrhythmia.
- Relative adrenal insufficiency: Accelerated cortisol metabolism in severe thyrotoxicosis depletes cortisol reserves, contributing to haemodynamic instability.
Common Precipitants
| Precipitant | Mechanism / Notes |
|---|---|
| Infection / sepsis | Most common trigger; cytokine-mediated increase in thyroid hormone release and peripheral conversion |
| Surgery / anaesthesia | Thyroid or non-thyroid surgery; manipulation of thyroid gland; inadequate pre-operative euthyroidism |
| Abrupt antithyroid drug cessation | Rebound hormone surge in Graves' disease |
| Radioiodine (RAI) therapy | Radiation thyroiditis with acute hormone release; pre-treat with antithyroid drugs if large gland or high fT4 |
| Iodine load | IV contrast for CT, amiodarone (both initiation and withdrawal — Jod-Basedow phenomenon or Wolff–Chaikoff failure) |
| Trauma / DKA / PE | Acute physiological stress; diabetic ketoacidosis is an under-recognised trigger |
| Parturition | Labour and delivery in undiagnosed or poorly controlled Graves' disease |
| Excessive thyroid hormone ingestion | Factitious thyrotoxicosis or intentional self-harm with levothyroxine |
Clinical pearl: Always search for and treat the precipitant concurrently. Failure to identify the trigger (e.g., occult infection, medication non-adherence) is the most common reason for refractory storm.
Clinical Features & Scoring (Burch–Wartofsky)
Cardinal Features
- Hyperthermia: Temperature ≥38.5°C, often 39.5–41°C; diaphoretic, flushed skin.
- Cardiovascular: Tachycardia (HR >140 bpm) disproportionate to fever; systolic hypertension with wide pulse pressure; atrial fibrillation; high-output heart failure; cardiogenic shock.
- Neurological: Agitation, restlessness, anxiety progressing to delirium, psychosis, seizures, stupor, or coma (thyroid encephalopathy).
- Gastrointestinal: Nausea, vomiting, profuse diarrhoea, abdominal pain; hepatic dysfunction with conjugated hyperbilirubinaemia (jaundice).
- Respiratory: Tachypnoea, pulmonary oedema, respiratory failure.
- Miscellaneous: Goitre (may be absent in thyroiditis-induced storm), tremor, proximal myopathy, diaphoresis.
Burch–Wartofsky Point Scale (BWPS)
The BWPS is the most widely used scoring system for thyroid storm. It integrates thermoregulatory, cardiovascular, CNS, GI/hepatic, and precipitant parameters.
| Parameter | Criteria | Points |
|---|---|---|
| Temperature | 37.2–37.7 °C | 5 |
| 37.8–38.2 °C | 10 | |
| 38.3–38.8 °C | 15 | |
| 38.9–39.4 °C / ≥39.5 °C | 20 / 30 | |
| Heart rate | 100–109 / 110–119 bpm | 5 / 10 |
| 120–129 / 130–139 bpm | 15 / 20 | |
| ≥140 bpm | 25 | |
| Atrial fibrillation (add) | +10 | |
| CNS dysfunction | Absent | 0 |
| Mild (agitation) | 10 | |
| Moderate (delirium, psychosis, extreme lethargy) | 20 | |
| Severe (seizure, coma) | 30 | |
| GI / hepatic | Diarrhoea, nausea, vomiting, abdominal pain | 10 |
| Jaundice | 20 | |
| Precipitant history | Identifiable precipitant present | 10 |
| Heart failure | Peripheral oedema / bibasal crackles | 5 / 15 |
Impending
BWPS 25–44
Thyrotoxicosis with early systemic features; no overt organ dysfunction.
Setting: Monitored bed, aggressive antithyroid Rx, search for precipitant
Likely Storm
BWPS 45–69
Moderate multi-organ involvement; fever, tachycardia, CNS disturbance.
Setting: ICU / HDU admission, full four-pillar therapy
Definite Storm
BWPS ≥70
Severe multi-organ failure; coma, shock, jaundice; very high mortality.
Setting: ICU, consider rescue plasmapheresis or emergency thyroidectomy
Do not delay treatment: The BWPS is a diagnostic aid, not a prerequisite for treatment. If clinical suspicion is high, initiate emergency management immediately while scoring is being performed.
Investigations
Baseline Urgent Bloods
Essential
Thyroid function — fT4, fT3, TSH
MBS Item 66716. Expect markedly elevated fT4 and fT3 with suppressed TSH. T3 disproportionately elevated in T3 thyrotoxicosis. Results available within 2–4 h at most Australian laboratories.
Essential
Full blood count (FBC)
MBS Item 65070. Leucocytosis with left shift may indicate infection or stress response; thrombocytopaenia in severe cases.
Essential
Electrolytes, urea, creatinine (EUC)
MBS Item 66500. Dehydration, hypokalaemia (from GI losses), hyponatraemia, elevated creatinine in pre-renal AKI.
Essential
Liver function tests (LFT)
MBS Item 66515. Hepatic dysfunction common — elevated bilirubin (conjugated), transaminases, LDH. Differentiate from hepatic necrosis.
Essential
Coagulation — INR, APTT, fibrinogen
MBS Item 66530. DIC screening; coagulopathy may complicate emergency surgery.
Essential
Blood cultures × 2 sets
Infection is the most common precipitant; obtain before antibiotics.
Available
Arterial blood gas (ABG)
Lactate (tissue hypoperfusion), metabolic acidosis, A-a gradient (if respiratory compromise).
Available
Cortisol (random)
Relative adrenal insufficiency is common; do not delay hydrocortisone while waiting for result.
Available
Troponin
Demand ischaemia from extreme tachycardia; troponin elevation common without ACS.
Available
CK, LDH
Thyrotoxic myopathy / rhabdomyolysis screening.
Imaging & Other Investigations
Essential
12-lead ECG
Atrial fibrillation (most common arrhythmia), sinus tachycardia, ST changes, prolonged QT.
Essential
Chest X-ray
Pulmonary oedema, cardiomegaly, pneumonia (precipitant).
Available
Echocardiography (bedside / POCUS)
LV function, high-output state, pericardial effusion.
Referral
Thyroid uptake scan (Tc-99m or I-123)
Not acutely; helps differentiate Graves' (diffuse uptake) from thyroiditis (low uptake) post-recovery. Available at major metropolitan nuclear medicine centres.
Do NOT withhold treatment for test results: Thyroid function results take 2–4 hours. Initiate emergency management based on clinical scoring (BWPS). Serial TFTs should be performed every 12–24 h to monitor response.
Emergency Management
Management of thyroid storm follows four concurrent pillars. All interventions should be initiated simultaneously in the emergency department and continued in ICU/HDU.
The Four Pillars of Thyroid Storm Management
1
Block New Hormone Synthesis
Antithyroid drugs (thionamides) inhibit thyroid peroxidase, preventing new T4/T3 synthesis.
2
Block Hormone Release
Inorganic iodine (Lugol's / SSKI) acutely inhibits thyroid hormone secretion via the Wolff–Chaikoff effect. Must be given ≥1 h after PTU.
3
Block Peripheral Conversion & Adrenergic Effects
Beta-blockers and corticosteroids reduce T4→T3 conversion and counteract catecholamine excess.
4
Treat the Precipitant & Supportive Care
Source control for infection, fluid resuscitation, active cooling, ICU-level monitoring.
Pillar 1 — Antithyroid Drugs (Block Synthesis)
Propylthiouracil (PTU)
PTU · Thionamide · PREFERRED in storm
Mechanism
Blocks TPO (synthesis) AND 5'-deiodinase (peripheral T4→T3 conversion)
Adult dose
500 mg PO/NG loading → 250 mg PO/NG every 4 h
Paediatric dose
5–7 mg/kg/day divided Q6H; loading dose 5–10 mg/kg
Route
Oral or nasogastric (crush tablet); IV not available in Australia
Renal adjustment
No dose adjustment; dialysed — give supplemental dose post-HD
Key caution
Agranulocytosis (0.1–0.5%); FBC at baseline and if fever/sore throat
PBS status
✔ PBS General Benefit
Carbimazole
Neo-Mercazole® · Thionamide · Alternative
Mechanism
Blocks TPO only (does NOT block peripheral conversion)
Adult dose
20–40 mg PO loading → 20 mg every 6–8 h; max 120 mg/day
Paediatric dose
0.5–1 mg/kg/day divided BD–TDS
Note
Second-line in storm (no peripheral conversion block); preferred for non-storm Graves' disease in Australia
PBS status
✔ PBS General Benefit
PTU is first-line in thyroid storm (not carbimazole) because it blocks peripheral T4→T3 conversion in addition to synthesis. Reserve carbimazole for non-storm Graves' disease management.
Pillar 2 — Inorganic Iodine (Block Hormone Release)
Lugol's Iodine / SSKI
Strong iodine solution · Aqueous iodine
Adult dose
5–10 drops (0.25–0.5 mL SSKI) PO TDS in water or milk; or Lugol's 4–8 drops TDS
Timing
MUST be given ≥1 hour AFTER the first PTU dose — otherwise iodine fuels new hormone synthesis
Mechanism
Wolff–Chaikoff effect: high iodide transiently inhibits organification and hormone release
Paediatric
1–5 drops SSKI PO TDS (age/weight-adjusted); discuss with endocrinology
PBS status
⚠ Not PBS-listed (hospital supply)
Timing is critical: Never give iodine before or without prior PTU administration. The iodine load can paradoxically worsen storm by providing substrate for unchecked hormone synthesis (Jod-Basedow effect) in the absence of thionamide blockade.
Pillar 3 — Beta-Blockers & Corticosteroids
Beta-Blockers
Propranolol
Inderal® · Non-selective β-blocker · PREFERRED
Mechanism
β-blockade reduces HR/BP + inhibits 5'-deiodinase (peripheral T4→T3 conversion)
Adult dose — oral
40–80 mg PO every 6 h; titrate to HR <100 bpm
Adult dose — IV
1 mg slow IV over 1 min; repeat every 5 min up to 5 mg; then infusion 1–10 mg/h
Paediatric
0.5–1 mg/kg/day divided Q6–8H PO; IV 0.01–0.15 mg/kg slow bolus
Caution
Avoid in decompensated heart failure (low EF), severe bronchospasm, cocaine-induced thyrotoxicosis
PBS status
✔ PBS General Benefit
Esmolol
Brevibloc® · Ultra-short-acting β1-selective
Use
If propranolol contraindicated or haemodynamic instability; easier to titrate
Adult dose
500 μg/kg IV loading over 1 min → 50–200 μg/kg/min infusion
PBS status
⚠ Hospital authority
Corticosteroids
Hydrocortisone
Solu-Cortef® · Glucocorticoid · PREFERRED
Adult dose
100 mg IV bolus then 100 mg IV every 6–8 h
Mechanism
Treats relative adrenal insufficiency + inhibits peripheral T4→T3 conversion
Paediatric
1–2 mg/kg IV every 6–8 h (max 100 mg/dose)
PBS status
✔ PBS General Benefit
Dexamethasone
Dexamethasone · Alternative corticosteroid
Adult dose
2 mg IV every 6 h
Advantage
Interferes less with serum cortisol assay (useful if adrenal axis assessment planned)
PBS status
✔ PBS General Benefit
Pillar 4 — Supportive Care & Treat Precipitant
| Intervention | Details |
|---|---|
| ICU / HDU admission | All patients with definite or likely storm (BWPS ≥45); continuous telemetry, invasive BP if shocked |
| IV fluid resuscitation | Isotonic crystalloid (0.9% NaCl or Hartmann's) 1–2 L bolus then 100–200 mL/h; monitor for fluid overload (high-output HF) |
| Active cooling | Paracetamol 1 g PO/IV QID (avoid aspirin — displaces T4 from TBG); ice packs, cooling blankets, evaporative cooling. Avoid dantrolene (unproven) |
| Infection source control | Broad-spectrum antibiotics if sepsis suspected (per eTG Antibiotic); blood cultures before first dose |
| Cholestyramine | 4 g PO QDS — reduces enterohepatic recycling of thyroid hormones; adjunctive, not a substitute for thionamides |
| VTE prophylaxis | Enoxaparin 40 mg SC OD (or 20 mg if CrCl <30); hyperthyroidism is prothrombotic |
| Avoid | Aspirin (↑ free T4), excessive sedation (respiratory depression), iodinated contrast (fuels hormone synthesis unless PTU on board) |
Adjunctive & Rescue Therapies
| Therapy | Indication | Notes |
|---|---|---|
| Plasmapheresis / plasma exchange | Refractory storm; severe organ failure unresponsive to 24–48 h of standard Rx | Rapidly reduces circulating T4/T3; available at major tertiary centres (e.g., RPA, Royal Melbourne, RBWH); discuss with nephrology/haematology |
| Emergency thyroidectomy | Last resort; refractory to medical Rx or contraindications to all medical options | Near-total thyroidectomy; requires experienced endocrine surgeon; pre-optimise with PTU + β-blocker + iodine for ≥1 h; high surgical risk |
| Potassium iodide (KI) via IV | If unable to take PO/NG and SSKI unavailable | Not routinely available in Australian hospitals; sodium iodide 500 mg IV over 24 h is an alternative (sourced through Special Access Scheme) |
| Bile-acid sequestrants | Adjunct to reduce enterohepatic recycling | Cholestyramine 4 g PO QDS or colestipol; separate from other medications by 1–2 h |
Treatment Timeline
T = 0 min
IV access, bloods (TFT, FBC, EUC, LFT, coag, cultures), ECG, CXR. Begin continuous monitoring. PTU 500 mg PO/NG stat. Propranolol 1 mg IV slow bolus. Hydrocortisone 100 mg IV stat.
T = 60 min
Lugol's iodine 5–10 drops PO TDS (must be ≥1 h after PTU). Continue propranolol titration. IV crystalloid bolus if hypotensive. Paracetamol 1 g IV/PO. Active cooling measures.
T = 2–4 h
ICU transfer. Cholestyramine 4 g PO QDS. Antibiotics if sepsis suspected. Discuss with endocrinology on-call. VTE prophylaxis.
T = 12 h
Repeat TFTs (fT4, fT3, TSH). Assess clinical response — HR, temperature, GCS. Adjust PTU to 250 mg Q4H. Ongoing ICU monitoring.
T = 24–48 h
Expect improvement in HR, temperature, and consciousness. If no improvement — consider refractory storm: escalate to plasmapheresis or discuss emergency thyroidectomy. Serial TFTs Q12–24 h.
T = 48–72 h
Transition from PTU to carbimazole 20 mg TDS (if ongoing thionamide Rx planned). Commence weaning of iodine (stop after 7–10 days). Wean β-blocker and corticosteroid over days.
Discharge planning: Once stabilised, arrange outpatient endocrinology follow-up within 1–2 weeks. Plan definitive treatment (RAI, surgery, or long-term thionamide). Ensure GP correspondence and patient education regarding medication adherence, signs of recurrence, and agranulocytosis precautions.
Special Populations
Pregnancy
PTU is preferred in the first trimester (carbimazole associated with aplasia cutis).
Switch to carbimazole after first trimester if continued thionamide needed (lower hepatotoxicity risk). Fetal thyrotoxicosis can occur — monitor fetal HR. Avoid radioactive iodine absolutely. Propranolol acceptable short-term; avoid atenolol (IUGR). Liaise with obstetric medicine / maternal-fetal medicine.
Paediatrics
Thyroid storm in children is rare but high-mortality; usually in adolescent Graves' disease.
PTU 5–10 mg/kg loading then 5–7 mg/kg/day divided Q6H. Propranolol 0.5–1 mg/kg/day PO or 0.01–0.15 mg/kg IV. Hydrocortisone 1–2 mg/kg IV Q6–8H. Lugol's dose: 1–5 drops SSKI TDS (weight-adjusted). ICU admission mandatory. Discuss with paediatric endocrinology at tertiary centre (e.g., Children's Hospital at Westmead, RCH Melbourne).
Elderly
Higher risk of AF, heart failure, and thyrotoxic periodic paralysis.
Amiodarone-induced thyrotoxicosis (AIT) is a common precipitant in the elderly. Type 1 AIT (excess synthesis) — add PTU; Type 2 AIT (destructive thyroiditis) — corticosteroids alone. Many patients are on anticoagulants — assess bleeding risk. Renal impairment common — adjust enoxaparin dose. β-blocker caution in bradycardia / heart block.
Renal Impairment
PTU — no dose adjustment required; supplemental dose after haemodialysis.
Avoid NSAIDs for fever (nephrotoxic). Enoxaparin dose reduction for CrCl <30 mL/min. IV fluid resuscitation — avoid overload, monitor daily weights and urine output. Cholestyramine may worsen electrolyte disturbance. Consider nephrology input if AKI requiring RRT.
Hepatic Impairment
Hepatic dysfunction is a feature of storm itself (cholestatic pattern).
PTU hepatotoxicity risk — monitor LFTs every 12–24 h; differentiate storm-related cholestasis from drug-induced liver injury. Carbimazole also hepatotoxic (cholestatic). Corticosteroids may be beneficial for storm-associated hepatitis. Avoid hepatotoxic medications. MELD score if liver transplant considered.
Immunocompromised
Infection trigger more likely and may be occult.
Lower threshold for broad-spectrum antibiotics (include fungal cover if risk factors). PTU-associated agranulocytosis risk compounded by baseline cytopenias — monitor FBC closely. Consider immunodeficiency-related thyroiditis as a cause of thyrotoxicosis. Post-allogeneic HSCT patients may have concurrent GVHD of the thyroid.
Aboriginal and Torres Strait Islander Health Considerations
Aboriginal and Torres Strait Islander Health
📚 References
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