Thyroid Storm
Life-threatening hyperthyroidism with multisystem decompensation; mortality 10-30%.
Also known as: thyroid storm, thyrotoxic crisis, thyrotoxic storm
Overview
Severe, life-threatening exacerbation of thyrotoxicosis characterized by hyperpyrexia, marked tachycardia, CNS dysfunction, and multi-organ decompensation. Clinical diagnosis (Burch-Wartofsky Point Scale) — do not wait for thyroid function tests to act.
Epidemiology
Uncommon (<10% of hospitalized thyrotoxic patients), but mortality 10-30%. Most cases occur in patients with known or unrecognized Graves disease or toxic nodular goiter. Often precipitated by an identifiable trigger.
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Risk factors
- Underlying Graves disease (most common), toxic multinodular goiter, toxic adenoma
- Precipitants: infection, surgery (thyroid or non-thyroid), trauma, MI, stroke, DKA, parturition
- Iodine load (contrast, amiodarone), thionamide non-adherence or discontinuation
- RAI therapy in inadequately blocked patient
- Vigorous palpation of an unprepared thyroid
Pathophysiology
Acute elevation of free thyroid hormone combined with increased tissue responsiveness produces a hypermetabolic crisis. Increased beta-adrenergic receptor sensitivity drives tachycardia, fever, and CNS hyperactivity. Cytokine release from a precipitating stressor compounds systemic decompensation.
Clinical presentation
Symptoms
- Marked agitation, delirium, psychosis, seizure, or coma
- Profuse sweating, drenched bedding
- Severe nausea, vomiting, diarrhea, abdominal pain
- Palpitations, chest pain, dyspnea
- History of recent thyroid surgery, radioiodine, or noncompliance with thionamides
Signs / physical exam
- Hyperpyrexia (often >40°C), drenching diaphoresis
- Sinus tachycardia >140 or atrial fibrillation with rapid response, hypertension followed by hypotension/shock
- Jaundice (poor prognostic sign), hepatomegaly
- Goiter ± thyroid bruit, exophthalmos (Graves)
- Pulmonary edema, signs of high-output heart failure
Classic findings
Burch-Wartofsky Point Scale (BWPS): score ≥45 highly suggestive, 25-44 impending storm, <25 unlikely. Domains: temperature, CNS, GI/hepatic, CV (tachycardia/CHF/AF), precipitating event.
Differential diagnosis
- Sepsis — Fever, tachycardia, AMS overlap; obtain cultures and treat empirically; storm can coexist
- Heat stroke — Hot dry skin, exertional or environmental exposure; treat with cooling
- Neuroleptic malignant syndrome — Antipsychotic exposure, lead-pipe rigidity, elevated CK
- Serotonin syndrome — Serotonergic drug exposure, clonus, hyperreflexia
- Malignant hyperthermia — Anesthetic trigger, masseter rigidity, hypercarbia; treat with dantrolene
- Pheochromocytoma crisis — Episodic hypertension, headache, sweating; metanephrines
- Cocaine/sympathomimetic toxicity — Drug exposure history, mydriasis, hypertension
- Acute alcohol or sedative withdrawal — Tremor, tachycardia, agitation; benzodiazepine response
Diagnostic workup
Diagnostic criteria
Clinical diagnosis using BWPS or Japanese Thyroid Association criteria. Don't wait for hormone levels.
Labs
- TSH (suppressed), free T4, free T3 (markedly elevated) — confirm diagnosis but do not delay treatment
- CBC, CMP (LFTs often elevated, hyperglycemia, hypercalcemia), coagulation studies
- Cardiac troponin, BNP, lactate
- Blood cultures, urinalysis, lipase if abdominal symptoms
- Pregnancy test in reproductive-age women
Imaging
- ECG (sinus tachycardia, AFib, ischemia)
- CXR (heart failure, pneumonia)
- Identify and image precipitant (CT for infection, abdomen, or trauma as indicated)
Diagnostic algorithm
| Step | Agent | Dose | Mechanism |
|---|---|---|---|
| 1 | Propranolol | 60-80 mg PO q4h or 0.5-1 mg IV | Blocks adrenergic effects + T4→T3 conversion |
| 2 | PTU (preferred) or methimazole | PTU 500-1000 mg load then 250 mg q4h | Blocks new hormone synthesis (+ T4→T3 for PTU) |
| 3 (≥1 h after #2) | SSKI / Lugol's iodine | SSKI 5 drops PO q6h | Blocks hormone RELEASE (Wolff-Chaikoff) |
| 4 | Hydrocortisone or dexamethasone | Hydrocort 100 mg IV q8h or dex 2 mg q6h | Blocks T4→T3, treats relative adrenal insufficiency |
| 5 | Supportive | Cooling, IVF, treat trigger | Acetaminophen NOT aspirin; ICU |
Complications
- High-output heart failure, atrial fibrillation, embolic stroke
- Multi-organ failure, hepatic failure (jaundice carries poor prognosis)
- Shock and death (mortality 10-30%)
- Seizure, coma
- Adrenal crisis if cortisol not co-administered
PANCE pearls
- ORDER MATTERS: beta-blocker first, then thionamide, then iodine AT LEAST 1 hour later (iodine before thionamide can fuel synthesis), then steroids.
- PTU > methimazole in storm because PTU blocks peripheral T4→T3 conversion.
- Acetaminophen for fever — never aspirin, which displaces thyroid hormone from binding proteins and worsens the crisis.
- Burch-Wartofsky ≥45 = highly likely storm. Don't wait for TFTs to start treatment.
- Look for the precipitant — infection is the most common trigger and must be identified and treated.
References
- ATA 2016 — 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism — Thyroid Storm section (Ross et al., Thyroid 2016)
- Burch & Wartofsky 1993 — Life-Threatening Thyrotoxicosis: Thyroid Storm (Burch & Wartofsky, Endocrinol Metab Clin North Am 1993)
- JTA 2016 — Japan Thyroid Association Guidelines for the Management of Thyroid Storm (Satoh et al., Endocr J 2016)
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