Endocrine

Thyroid storm: recognition and CCS-style management

Clinical Overview and When to Suspect Thyroid Storm

— Infection (most common precipitant in hospitalized patients)

— Thyroid or non-thyroid surgery in unprepared patient

— Iodinated contrast load, amiodarone exposure, recent radioactive iodine

— Abrupt antithyroid drug withdrawal, DKA, trauma, MI, parturition, PE

— Fever >38.5°C + tachycardia disproportionate to fever + AMS in a patient with goiter, exophthalmos, or known Graves

— New AF with rapid ventricular response in a younger patient, especially with weight loss or tremor

— "Apathetic" thyrotoxicosis in elderly: weight loss, AF, depression, proximal weakness — fever may be blunted

Board pearl: Thyroid storm is a clinical diagnosis — do NOT wait for TSH/free T4 results to begin treatment. Empirically initiate the multi-drug regimen when BWPS ≥45 in a patient with biochemical or historical thyrotoxicosis.

CCS pearl: On a CCS case, the moment you suspect storm, your first three orders should be: continuous cardiac monitor, IV access × 2, and "thyroid storm protocol" — then sequence propranolol → PTU → iodine → hydrocortisone in the correct order with the clock advancing in 15–30 minute increments.

Definition: Life-threatening decompensation of thyrotoxicosis with multi-organ dysfunction — fever, CNS changes, cardiovascular failure, GI/hepatic dysfunction. Mortality 10–30% even with treatment.

Pathophysiology: Surge in free T4/T3 with increased β-adrenergic receptor sensitivity. Absolute hormone levels do NOT distinguish storm from uncomplicated thyrotoxicosis — clinical syndrome defines it.

Common precipitants (must hunt for trigger):

When to suspect in the ED:

Burch–Wartofsky Point Scale (BWPS): ≥45 highly suggestive, 25–44 impending storm, <25 unlikely. Scores temperature, CNS, GI/hepatic, cardiovascular, AF, CHF, precipitant history. Japanese Thyroid Association (JTA) criteria are an alternative — requires thyrotoxicosis plus CNS or multi-system involvement.

Presentation Patterns and Key History

— Hyperpyrexia: Often 39–41°C, disproportionate to any identified infection. Diaphoresis is profuse.

— CNS dysfunction: Agitation, delirium, psychosis, seizures, or frank coma. Even mild confusion in a thyrotoxic patient earns BWPS points.

— Cardiovascular hyperactivity: Sinus tach >140, AF with RVR, high-output heart failure, hypotension as a late/ominous sign.

— Nausea, vomiting, diarrhea (volume loss compounds hemodynamics)

— Jaundice, transaminitis — hepatic congestion from high-output failure or direct hormone effect; jaundice is a poor prognostic sign

— Abdominal pain mimicking acute abdomen

— Known Graves disease, toxic multinodular goiter, recent thyroidectomy

— Recent CT with contrast, amiodarone start, lithium, immune checkpoint inhibitors (ipilimumab, pembrolizumab)

— Methimazole or PTU nonadherence — common in young women

— Postpartum state (4–12 weeks) — postpartum thyroiditis or Graves flare

— Recent radioactive iodine (storm 1–2 weeks post-RAI from hormone release)

— Weight loss, anorexia, lethargy, depression, isolated AF, proximal myopathy

— Fever/agitation may be absent — easy miss; thyroid storm in a 75-year-old may look like "failure to thrive with AF"

Key distinction: Sepsis vs. thyroid storm — both have fever and tachycardia, but storm has wide pulse pressure, hyperdynamic precordium, tremor, lid lag, and tachycardia out of proportion to fever. Both can coexist; treat empirically for both if uncertain.

Step 3 management: In any young woman with new-onset AF, palpitations, and unexplained weight loss, order TSH before rate-control titration — undiagnosed thyrotoxicosis changes your β-blocker dosing and adds antithyroid therapy. This is a frequent ambulatory miss that boards love to test.

Classic triad to anchor on:

GI/hepatic clues:

Historical red flags to elicit quickly:

Apathetic thyrotoxicosis (elderly):

Physical Exam Findings and Hemodynamic Assessment

— Temp often >38.5°C (BWPS: 37.2–37.7 = 5 pts, ≥40 = 30 pts)

— HR 130–200; pulse pressure widened (e.g., 160/50)

— Tachypnea, hypoxia if pulmonary edema from high-output CHF

— Late: hypotension, narrowed pulse pressure — cardiovascular collapse imminent

— Diffuse goiter with bruit (Graves) — pathognomonic when present

— Lid lag, lid retraction, proptosis, ophthalmoplegia, chemosis (Graves orbitopathy)

— Pretibial myxedema on shins (Graves dermopathy)

— Hyperdynamic apical impulse, loud S1, systolic flow murmur

— Irregularly irregular rhythm if AF (10–35% of storm patients)

— JVD, S3, rales if high-output failure progressing to decompensation

— Fine resting tremor of outstretched hands

— Hyperreflexia with clonus

— Warm, moist, velvety skin; onycholysis (Plummer's nails)

— Proximal muscle weakness — patient cannot rise from chair without arms

— Hyperactive bowel sounds, diffuse tenderness, hepatomegaly with possible RUQ tenderness if congestive hepatopathy

— Hyperdynamic/warm shock: wide pulse pressure, bounding pulses, warm extremities — typical early storm

— Cardiogenic/cold shock: narrow pulse pressure, cool extremities, pulmonary edema — late, ominous; consider thyrotoxic cardiomyopathy

— Mixed (storm + sepsis): very common; cover empirically

Board pearl: A thyroid bruit in a febrile, tachycardic, agitated patient is essentially diagnostic until proven otherwise — begin storm treatment immediately.

CCS pearl: Document a focused neuro and cardiac exam on arrival; the case will reward you for recognizing AF and AMS as separate BWPS contributors, each driving 10–20 points toward the storm threshold.

Vitals on arrival:

Head/neck:

Cardiovascular:

Neuro/skin:

GI exam:

Hemodynamic phenotypes to recognize:

Diagnostic Workup — Initial Labs, Imaging, ECG, Biomarkers

— TSH, free T4, free T3, total T3 — TSH suppressed (<0.01), free T4 and T3 elevated. Absolute level does not correlate with severity.

— CBC with diff — leukocytosis common from storm itself, but obtain blood/urine cultures to evaluate precipitating infection

— CMP — hyperglycemia, hypercalcemia (10–20%), transaminitis, hyperbilirubinemia

— Coags — PT may be prolonged from hepatic dysfunction

— Cardiac troponin, BNP — to assess for demand ischemia and high-output CHF

— Lactate, ABG — type B lactic acidosis from increased metabolism

— β-hCG in any female of reproductive age — changes drug selection (PTU in 1st trimester, methimazole 2nd/3rd)

— Cortisol level before steroids if relative adrenal insufficiency is suspected, but do not delay hydrocortisone

— Sinus tachycardia (most common)

— Atrial fibrillation/flutter with rapid ventricular response

— Nonspecific ST-T changes, demand ischemia, occasional STEMI mimickers

— Prolonged QT and rare polymorphic VT

— CXR: pulmonary edema, cardiomegaly, evaluate for pneumonia

— Bedside echo if cardiomyopathy suspected — often shows preserved or hyperdynamic LV early, dilated with reduced EF late

— CT/imaging only as needed for precipitant; avoid iodinated contrast if possible (worsens storm via Jod-Basedow until iodine load is therapeutically harnessed)

Key distinction: Subclinical hyperthyroidism has suppressed TSH with normal free T4/T3 and is NOT a cause of storm. Storm requires overt biochemical thyrotoxicosis (suppressed TSH + elevated free hormones) plus clinical decompensation.

Step 3 management: Order labs and treatment in parallel, not in series. The board-correct sequence is: monitor + IVF + cooling → propranolol → PTU/methimazole → iodine (≥1 hour after antithyroid drug) → hydrocortisone → treat precipitant.

Send simultaneously with initiating treatment — do NOT delay therapy:

ECG findings:

Imaging:

Diagnostic Workup — Advanced or Confirmatory Studies

— TSH receptor antibodies (TRAb) / thyroid-stimulating immunoglobulins (TSI): positive in Graves

— Radioactive iodine uptake (RAIU) and scan: diffuse high uptake in Graves; patchy/nodular in toxic multinodular goiter; single hot nodule in toxic adenoma; low uptake in thyroiditis (subacute, painless, postpartum), factitious thyrotoxicosis, or iodine-induced

— Thyroglobulin: elevated in thyroiditis, low in factitious thyrotoxicosis (exogenous levothyroxine ingestion) — a high-yield distinction

— Thyroid ultrasound with Doppler: increased vascularity ("thyroid inferno") in Graves; nodules in MNG; hypoechoic areas in thyroiditis

— Recent iodinated contrast (wait 4–8 weeks)

— Pregnancy (absolute contraindication) — use ultrasound instead

— Breastfeeding

— Blood/urine cultures, viral panel, chest imaging for infection

— Troponin trend, echo for ACS/cardiomyopathy

— CT-PA only if PE strongly suspected (weigh iodine load)

— Medication reconciliation: amiodarone, lithium, interferon, immune checkpoint inhibitors, recent contrast

— Free T4 q24h to track response; expect decline over 24–48 h with PTU

— LFTs daily — PTU hepatotoxicity vs. storm hepatopathy

— CBC for agranulocytosis (rare but devastating; check baseline WBC before starting thionamides)

Board pearl: Differentiating Graves from thyroiditis is critical because thyroiditis does NOT respond to antithyroid drugs (no ongoing synthesis — hormone is leaking from damaged follicles). In thyroiditis-induced storm, β-blockade and steroids are the mainstays; PTU/methimazole are ineffective.

CCS pearl: After stabilization on the inpatient ward, order TRAb and a thyroid ultrasound while the patient is on antithyroid therapy. Defer RAIU until you can stop iodine and have a contrast-free window — typically arranged at outpatient endocrine follow-up.

Confirming the etiology of thyrotoxicosis (after stabilization):

Cannot perform RAIU if:

Workup of precipitant:

Repeat labs:

Risk Stratification and First-Line Management Logic

— ≥45: highly suggestive of storm — treat aggressively

— 25–44: impending storm — treat as storm if clinical gestalt fits

— <25: storm unlikely

— Any patient meeting storm criteria → ICU admission for continuous telemetry, frequent neuro checks, and titratable therapy

— Endocrinology consult immediately; cardiology if AF/CHF

— Block β-receptors (propranolol) — controls adrenergic surge

— Block synthesis (PTU or methimazole) — stops new hormone production

— Block release (iodine — Lugol's or SSKI) — must be given ≥1 hour AFTER thionamide to prevent Jod-Basedow effect (substrate fueling more synthesis)

— Block peripheral conversion (PTU, propranolol, hydrocortisone, iodinated contrast agents like iopanoate)

— Treat precipitant (antibiotics for infection, etc.) + supportive care

— IV crystalloid (D5NS often used — glycogen depleted) — 1–2 L bolus, then titrate to hemodynamics; caution if CHF

— Active cooling: acetaminophen 650–1000 mg PR/PO q6h, cooling blankets, ice packs

— Avoid aspirin/NSAIDs — displace T4 from TBG, raising free T4 and worsening storm

— Treat agitation with benzodiazepines (lorazepam) — also reduces sympathetic tone

— DVT prophylaxis once stabilized

— NPO if AMS; consider NG tube for enteral antithyroid drugs if needed

Step 3 management: The single most tested sequencing error is giving iodine before PTU/methimazole. Always thionamide first, then wait ≥60 minutes, then iodine. Reverse order can transiently worsen thyrotoxicosis.

Board pearl: Acetaminophen, not aspirin, is the antipyretic of choice in thyroid storm.

Burch–Wartofsky Point Scale interpretation:

Disposition decision:

Five pillars of therapy (mnemonic: "Block, Block, Block, Block, Treat"):

Supportive care orders on arrival:

Pharmacotherapy — First-Line Drug Regimen

— Propranolol 60–80 mg PO q4h or 0.5–1 mg IV slow push, repeat q15 min titrated to HR <100

— Non-selective: blocks β1 (HR/contractility) AND inhibits peripheral T4→T3 conversion at high doses

— Alternative: esmolol infusion (50–200 mcg/kg/min) — preferred if reactive airway disease, cardiomyopathy, or need rapid titration

— Caution: Decompensated CHF or asthma — use cautiously; esmolol or short-acting agent first

— PTU 500–1000 mg PO/NG load, then 250 mg q4h (1000 mg/d total)

— PTU blocks synthesis AND peripheral T4→T3 conversion (methimazole does not block conversion) — preferred in acute storm and 1st trimester pregnancy

— Methimazole 20–25 mg PO q4–6h (60–80 mg/d) — preferred for maintenance after acute crisis resolves (longer half-life, less hepatotoxicity)

— Both can cause agranulocytosis (0.3%) and hepatotoxicity (PTU > methimazole — black box for fulminant hepatic failure)

— SSKI 5 drops PO q6h OR Lugol's solution 8 drops q6h

— Blocks hormone release from gland (Wolff–Chaikoff effect)

— If iodine allergy: lithium carbonate 300 mg q6–8h (monitor levels 0.6–1.0)

— Hydrocortisone 100 mg IV load, then 100 mg q8h (or dexamethasone 2 mg q6h)

— Blocks T4→T3 conversion, treats potential relative adrenal insufficiency, may have direct benefit in Graves

— Cholestyramine 4 g PO q6h — interrupts enterohepatic recirculation of thyroid hormone

CCS pearl: Order set sequence on the CCS interface: propranolol IV → PTU NG → wait 1 hour → SSKI PO → hydrocortisone IV. Advance clock in 30-min increments to recheck vitals. Add empiric ceftriaxone if infection suspected.

Board pearl: "PTU in Pregnancy (1st trimester) and Plummeting Patient (storm)"; methimazole everywhere else.

1. β-blocker — propranolol (drug of choice):

2. Thionamide — PTU preferred in storm:

3. Iodine — given ≥1 hour AFTER thionamide:

4. Glucocorticoid:

5. Bile acid sequestrant (adjunct in severe cases):

Refractory Disease and Definitive Therapy

— Therapeutic plasma exchange (plasmapheresis): removes circulating T4/T3 and antibodies; bridge to thyroidectomy in refractory storm or when thionamides contraindicated (severe hepatotoxicity, agranulocytosis)

— Emergency thyroidectomy: rare but life-saving in iodine-induced storm or thionamide-intolerant patients — preceded by plasmapheresis + β-blockade + steroids + iodine for gland preparation

— Cholestyramine + high-dose steroids + iodinated contrast agents (iopanoic acid, ipodate — limited US availability) as additional T4→T3 conversion blockers

— Radioactive iodine (RAI) ablation (I-131):

— First-line definitive therapy for Graves and toxic nodular disease in nonpregnant adults

— Pretreat with methimazole to euthyroid state, then stop 3–5 days before RAI

— Risk: transient worsening of thyrotoxicosis 1–2 weeks post-RAI (release of preformed hormone) — restart antithyroid drugs and β-blocker

— Contraindicated in pregnancy, breastfeeding, severe active orbitopathy (can worsen — pretreat with prednisone)

— Total thyroidectomy: preferred for large goiters with compressive symptoms, suspected malignancy, moderate-severe Graves orbitopathy, pregnancy unresponsive to drugs, or patient preference. Requires euthyroid state preoperatively (β-blocker + thionamide + SSKI for 10–14 days).

— Long-term antithyroid drugs (methimazole 12–18 months): option for mild Graves with small goiter and low TRAb — ~50% remission rate

— Rate control with propranolol; cardioversion often unsuccessful until euthyroid

— Anticoagulation: controversial; consider in patients with CHA2DS2-VASc risk factors, LA enlargement, or CHF — heparin bridge to warfarin/DOAC

Step 3 management: The post-storm outpatient plan boards love: methimazole maintenance → endocrine clinic in 1–2 weeks → repeat TFTs in 4–6 weeks → definitive therapy (RAI or surgery) discussion once euthyroid. Document shared decision-making.

Escalation when standard regimen fails (no improvement in 24–48 h):

Definitive therapy after storm resolution (outpatient endocrine planning):

Management of AF in storm:

Special Populations — Elderly and Renal/Hepatic Impairment

— Often present with apathetic thyrotoxicosis — AF, weight loss, depression, CHF; fever and tremor may be absent

— Higher risk of demand ischemia, stroke from new AF, and decompensated heart failure

— β-blocker dosing: start lower (propranolol 10–20 mg q6h) and titrate; favor esmolol if CHF

— Higher mortality (up to 30%); lower threshold for ICU admission

— Drug interactions: warfarin clearance increases in thyrotoxicosis — INR may drop; will rise again as patient becomes euthyroid, requiring dose reduction

— Methimazole and PTU primarily hepatically metabolized — minimal dose adjustment needed for CKD

— Propranolol: dose adjustment usually unnecessary but monitor for bradycardia

— Lithium (if iodine alternative needed): dose-reduce in CKD, monitor levels closely (target 0.6–1.0 mEq/L) — narrow therapeutic window

— Avoid contrast if possible — both CIN risk and Jod-Basedow risk

— Fluid management trickier — diuretics may be needed if CHF coexists; avoid overaggressive crystalloid

— Methimazole preferred over PTU in pre-existing liver disease — PTU has black-box warning for fulminant hepatic failure

— Exception: 1st trimester pregnancy and acute storm — PTU still preferred for those windows; switch to methimazole as soon as feasible

— Monitor LFTs at baseline, weekly × 4, then monthly

— Stop thionamide if ALT >3× ULN that does not resolve or rises further

— Storm itself causes hepatic dysfunction — distinguishing storm hepatopathy from drug-induced injury requires trending LFTs against clinical improvement

Key distinction: In an elderly patient with new AF and CHF, always check TSH before assuming primary cardiac disease — thyrotoxic cardiomyopathy is reversible with definitive thyroid treatment, while standard rate control alone will fail.

Board pearl: A 70-year-old with weight loss, AF, and depression has apathetic hyperthyroidism until TSH proves otherwise — boards repeatedly test this stem.

Elderly:

Renal impairment:

Hepatic impairment:

Special Populations — Pregnancy, Pediatrics, and Postpartum

— Most common cause of thyrotoxicosis in pregnancy: Graves disease; also gestational transient thyrotoxicosis (hCG-mediated, 1st trimester, resolves by 14–18 weeks, no treatment)

— PTU in 1st trimester (methimazole teratogenic — aplasia cutis, choanal/esophageal atresia, "methimazole embryopathy")

— Switch to methimazole at 16 weeks (2nd trimester) — PTU carries fulminant hepatic failure risk

— Target: maternal free T4 in upper third of normal range using lowest effective dose — both drugs cross placenta and can cause fetal hypothyroidism/goiter

— β-blockers: propranolol short-term acceptable; avoid prolonged use (IUGR, neonatal hypoglycemia, bradycardia)

— Iodine: brief use (<7–10 days) acceptable in storm; prolonged use causes fetal goiter

— RAI contraindicated; thyroidectomy reserved for 2nd trimester if drug-intolerant

— Storm in pregnancy: delivery does not treat storm — stabilize mother first

— Postpartum thyroiditis: 5–10% of women; transient hyperthyroid phase 1–6 months postpartum, often followed by hypothyroid phase

— Low RAIU distinguishes from postpartum Graves flare

— Treat symptomatically with β-blockers; antithyroid drugs ineffective (no synthesis)

— Breastfeeding: methimazole ≤20 mg/d and PTU ≤450 mg/d compatible with nursing

— Rare; usually Graves

— Methimazole preferred (PTU has FDA pediatric black box for hepatic failure)

— Weight-based propranolol (1–2 mg/kg/day divided q6–8h)

— Definitive therapy: surgery preferred over RAI in young children due to long-term radiation concerns; RAI acceptable >5 years old

Step 3 management: Pregnant patient with palpitations, weight loss, tachycardia at 8 weeks gestation — check TSH, free T4, TRAb, and hCG. Distinguish Graves (positive TRAb, persistent) from gestational thyrotoxicosis (negative TRAb, resolves spontaneously, hyperemesis often present). Treatment differs entirely.

Board pearl: "PTU before 16, methimazole after" is the pregnancy switch boards love.

Pregnancy:

Postpartum:

Pediatric storm:

Complications and Adverse Outcomes

— Atrial fibrillation: 10–35% — increases stroke risk; rate control often refractory until euthyroid

— High-output heart failure progressing to dilated cardiomyopathy

— Demand ischemia/MI in patients with underlying CAD

— Cardiovascular collapse and shock — late, ominous, high mortality

— Thromboembolism — AF + hypercoagulable state of thyrotoxicosis

— Seizures, status epilepticus

— Coma

— Cerebrovascular accident (often embolic from AF)

— Long-term: persistent cognitive impairment in survivors

— Congestive hepatopathy from high-output failure

— Hyperbilirubinemia — independent predictor of mortality

— PTU-induced fulminant hepatic failure (rare but devastating)

— Agranulocytosis from thionamides (0.3%) — present with fever, sore throat; check CBC, stop drug immediately, do NOT switch to the other thionamide (cross-reactivity)

— Thrombocytopenia, vasculitis (ANCA-positive with PTU)

— Hypercalcemia, hyperglycemia

— Type B lactic acidosis from accelerated metabolism

— Hypokalemic periodic paralysis (especially Asian males — striking presentation with flaccid paralysis and low K)

— Hypothyroidism post-RAI or thyroidectomy — lifelong levothyroxine

— Worsening Graves orbitopathy post-RAI (pretreat with prednisone if moderate-severe eye disease)

— Adrenal crisis if undiagnosed concomitant adrenal insufficiency

— Older age, jaundice, CNS dysfunction, CHF, shock on presentation, DIC, multi-organ failure

— Overall mortality 10–30% despite optimal therapy

Key distinction: Sudden fever and sore throat in a patient on methimazole or PTU — assume agranulocytosis until CBC proves otherwise. Hold drug, draw labs, start broad-spectrum antibiotics if febrile and neutropenic.

CCS pearl: If WBC count returns <1500 with ANC <500, the case rewards "discontinue thionamide, do not substitute, start G-CSF if severe, plan definitive therapy (surgery after plasmapheresis or RAI)."

Cardiovascular:

Neurologic:

Hepatic:

Hematologic:

Metabolic:

Endocrine sequelae:

Mortality predictors:

When to Escalate Care — ICU, Consults, and Inpatient Triage

— Any patient meeting BWPS ≥45

— Hemodynamic instability, requiring vasopressors or inotropes

— Altered mental status, seizures, or coma

— Atrial fibrillation with RVR not controlled in ED

— Respiratory failure, pulmonary edema, or need for intubation

— Severe hyperthermia (>40°C) requiring active cooling

— Endocrinology — urgent bedside; guides thionamide dosing, plans definitive therapy

— Cardiology — if AF, CHF, demand ischemia, or cardiomyopathy

— Critical care — ICU co-management

— Surgery — if emergency thyroidectomy contemplated or precipitant requires surgery

— Infectious disease — if complex infection precipitant

— OB/MFM — if pregnant

— Apheresis — if plasmapheresis considered for refractory cases

— Hour 0: ED resuscitation, BWPS scoring, lab draws, initiate pharmacotherapy

— Hour 1–2: re-vital, ensure iodine given after thionamide, hydrocortisone on board, cooling effective

— Hour 4–6: ICU transfer, endocrine evaluation, source control of precipitant

— Hour 12–24: trend free T4/T3, LFTs, CBC; titrate β-blocker; expect HR and temperature to begin improving

— Day 2–4: clinical improvement, transition to oral regimen, taper steroids if stable

— Day 5–7: transfer to ward, plan outpatient endocrine follow-up and definitive therapy discussion

— Facility without ICU capability, endocrinology, or apheresis → transfer to tertiary center after stabilization

— Pregnant patients with storm → transfer to center with MFM and NICU

Step 3 management: Discharge from the ED is never appropriate for confirmed or impending storm. Even BWPS 25–44 with stable vitals warrants admission, telemetry, and inpatient endocrinology evaluation.

CCS pearl: On a CCS case, "transfer to ICU" should be ordered within the first 30 minutes of recognition — delayed ICU transfer is a frequent scoring deduction.

Automatic ICU admission criteria for thyroid storm:

Consultations to initiate from the ED:

Stepwise care escalation timeline:

Transfer indications:

Key Differentials — Other Causes of Thyrotoxicosis

— TRAb/TSI positive, diffuse goiter with bruit, orbitopathy, dermopathy

— Diffusely increased RAIU

— Most common cause of thyroid storm

— Older patients, longstanding nontoxic goiter that develops autonomy

— RAIU shows patchy uptake; multiple "hot" nodules

— No orbitopathy; common in iodine-deficient regions

— Storm often precipitated by iodine load (contrast, amiodarone)

— Single hyperfunctioning nodule; suppresses surrounding gland

— RAIU shows single hot nodule with suppressed background

— Post-viral, painful tender goiter, fever, elevated ESR/CRP

— Low RAIU (key finding)

— Self-limited; treat with NSAIDs (but avoid aspirin in storm) and β-blockers; steroids if severe

— Triphasic course: thyrotoxic → hypothyroid → euthyroid

— Autoimmune, often postpartum; nontender goiter

— Low RAIU; positive TPO antibodies

— 5–10% of women within 12 months postpartum; transient

— Amiodarone (AIT type 1: iodine load → hyperthyroidism in autonomous gland; AIT type 2: destructive thyroiditis) — distinguish with color-flow Doppler (increased in type 1, absent in type 2)

— Lithium, interferon-α, immune checkpoint inhibitors (ipilimumab, pembrolizumab, nivolumab)

— Iodinated contrast (Jod-Basedow phenomenon)

— Exogenous levothyroxine; suppressed thyroglobulin, low RAIU

— Rare ovarian teratoma with thyroid tissue; low neck RAIU, pelvic uptake

— Inappropriately normal/elevated TSH with elevated free T4/T3 — rare

Key distinction: Tender goiter + fever + elevated ESR + low RAIU → subacute thyroiditis, NOT Graves. Treatment is supportive; thionamides are useless.

Graves disease (60–80% of thyrotoxicosis):

Toxic multinodular goiter (Plummer disease):

Toxic adenoma:

Subacute (de Quervain) thyroiditis:

Painless (silent/lymphocytic) thyroiditis:

Postpartum thyroiditis:

Drug-induced thyrotoxicosis:

Factitious thyrotoxicosis:

Struma ovarii:

TSH-secreting pituitary adenoma:

Key Differentials — Mimics of Thyroid Storm

— Shared: fever, tachycardia, AMS, hypotension

— Distinguishing: no goiter/orbitopathy, normal or low TSH only if sick euthyroid (low T3, normal/low T4, normal/low TSH)

— Both can coexist — sepsis is the most common precipitant; treat empirically for both

— Environmental exposure or exertion; core temp often >40°C; anhidrosis in classic heat stroke

— Normal TFTs

— Treatment: rapid cooling, no role for thionamides

— Mydriasis, hypertension, hyperthermia, agitation

— Tox screen positive; no goiter; recent exposure history

— "Hot as a hare, dry as a bone, red as a beet, mad as a hatter" — but dry skin distinguishes from storm's diaphoresis

— Recent serotonergic drug; clonus, hyperreflexia prominent in lower extremities

— Antipsychotic exposure; "lead-pipe" rigidity, elevated CK, hyperthermia, autonomic instability

— Volatile anesthetic or succinylcholine exposure; muscle rigidity, hypercarbia, rhabdomyolysis

— Treatment: dantrolene

— Paroxysmal hypertension, headache, diaphoresis, palpitations

— Elevated plasma metanephrines/urine catecholamines

— Critical: α-blockade before β-blockade to prevent unopposed α

— Tremor, tachycardia, agitation; history of dependence; responds to benzodiazepines

— Tachycardia, hypoxia, hemodynamic instability; D-dimer, CT-PA

— May coexist with or be precipitated by storm

Key distinction: Storm mimics share fever + tachycardia + AMS, but only thyroid storm has tremor, lid lag, goiter, and biochemical thyrotoxicosis as a unifying explanation. When in doubt, send TSH/free T4 early — results return same shift in most hospitals.

Board pearl: Hypertensive crisis + headache + diaphoresis without thyroid signs → think pheochromocytoma; giving propranolol alone can cause hypertensive emergency from unopposed α.

Sepsis/septic shock:

Heat stroke:

Sympathomimetic toxidrome (cocaine, methamphetamine, MDMA, bath salts):

Anticholinergic toxidrome:

Serotonin syndrome:

Neuroleptic malignant syndrome:

Malignant hyperthermia:

Pheochromocytoma crisis:

Alcohol/benzodiazepine withdrawal:

Pulmonary embolism:

Decompensated CHF or ACS:

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Methimazole 10–20 mg PO daily (transitioned from PTU after acute storm resolves and pregnancy excluded)

— Propranolol 20–40 mg PO q6h (or atenolol/metoprolol for compliance), taper as HR normalizes over 2–4 weeks

— Stop iodine, steroids tapered over days as clinical improvement sustained

— Calcium/vitamin D if planning thyroidectomy (postop hypocalcemia risk)

— Medication adherence is critical — abrupt discontinuation precipitated original storm in many patients

— Report immediately: fever, sore throat, mouth ulcers (agranulocytosis) — stop drug, go to ED, get CBC

— Report: jaundice, dark urine, RUQ pain, nausea (hepatotoxicity)

— Report: rash, joint pain (vasculitis, especially PTU)

— Avoid iodine excess: kelp, seaweed, iodinated contrast, amiodarone — alert all providers

— Smoking cessation — strongly worsens Graves orbitopathy

— Shared decision-making among three options:

— RAI ablation — outpatient, effective, but causes permanent hypothyroidism; contraindicated in pregnancy/severe orbitopathy

— Total thyroidectomy — definitive, rapid; risks: hypocalcemia, recurrent laryngeal nerve injury, requires surgical expertise

— Long-term methimazole — 12–18 months; ~50% remission for Graves

— Discuss in context of patient age, comorbidities, pregnancy plans, goiter size, orbitopathy

— Levothyroxine replacement lifelong post-thyroidectomy/RAI; target TSH 0.5–2.5; adjust q6 weeks after dose changes

— Annual TSH monitoring once stable

Step 3 management: A patient discharged after thyroid storm should leave with: (1) methimazole prescription, (2) β-blocker, (3) endocrinology appointment within 1–2 weeks, (4) lab order for TSH/free T4/CBC/LFTs in 2–4 weeks, (5) written warning sign instructions. Missing any of these is a frequent transition-of-care error tested on Step 3.

Discharge medication regimen (typical):

Patient education at discharge:

Definitive therapy planning (within 3–6 months):

After definitive therapy:

Follow-Up, Monitoring Parameters, and Counseling

— Endocrinology within 1–2 weeks post-discharge

— Labs at 2 weeks, then q4–6 weeks until euthyroid: TSH, free T4, free T3, CBC, LFTs

— Once euthyroid and stable: q3 months on maintenance methimazole

— After RAI or surgery: TSH q6 weeks until on stable levothyroxine dose, then annually

— CBC: baseline, then with any febrile illness — agranulocytosis monitoring (not routine scheduled CBCs per ATA — symptom-driven)

— LFTs: baseline, then q4–6 weeks for first 6 months, then periodically

— Discontinue if ALT >3× ULN persistently, ANC <1000, or vasculitis/rash

— As HR normalizes (typically 2–6 weeks), taper propranolol; stop once euthyroid and asymptomatic

— Adherence: stress lifelong implications of skipping doses

— Pregnancy planning: defer pregnancy until euthyroid; switch to PTU pre-conception or in 1st trimester

— Smoking cessation: tobacco doubles risk and severity of Graves orbitopathy; refer to cessation program, offer pharmacotherapy

— Diet: avoid iodine excess (kelp, seaweed, kosher salt fortified products in some regions); no need for iodine restriction otherwise

— Vaccinations: ensure influenza and pneumococcal up to date — infection is leading precipitant

— Cardiovascular risk reduction: long-term AF stroke risk persists; reassess CHA2DS2-VASc after euthyroid

— Refer to ophthalmology if proptosis, diplopia, decreased acuity, or color vision changes

— Pretreat with prednisone before RAI if moderate-severe orbitopathy

— Selenium 200 mcg/day for mild orbitopathy (some evidence)

— Long-standing thyrotoxicosis causes osteoporosis — DXA at baseline and follow-up, especially in postmenopausal women

Board pearl: The two most important post-storm counseling points: never stop methimazole abruptly and report fever/sore throat immediately — agranulocytosis is the silent killer of thionamide therapy.

Follow-up cadence after storm:

Monitoring on methimazole/PTU:

β-blocker tapering:

Counseling priorities:

Orbitopathy monitoring:

Bone health:

Ethical, Legal, and Patient Safety Considerations

— Patients with storm often have delirium/AMS — lack capacity for definitive therapy decisions (RAI vs. surgery)

— Acute lifesaving treatment proceeds under emergency exception (implied consent)

— Defer elective definitive therapy decisions until capacity restored; document clearly

— Surrogate decision-maker if prolonged incapacity; respect prior advance directives

— RAI is absolutely contraindicated; even inadvertent administration to a pregnant patient is a sentinel event — always document negative β-hCG before any RAI

— Joint counseling with patient and partner on teratogenicity of methimazole (1st trimester) and need for medication switching

— Discharge without endocrinology follow-up scheduled is a high-risk handoff — relapse and re-storm common

— Medication reconciliation must include: stopping iodine, transitioning PTU→methimazole, tapering steroids, β-blocker plan

— Communicate with PCP via discharge summary within 48 hours; include warning signs and lab plan

— Patients with limited health literacy or insurance access need social work involvement for medication affordability

— Giving iodine before thionamide — system-level error; build order set safeguards

— Aspirin or salicylates in storm — pharmacy alerts should flag

— Missing β-hCG before RAI in reproductive-age female — checklist mandatory

— Failure to recheck CBC in symptomatic patient on thionamide — agranulocytosis fatality

— Patients in AF post-storm may need driving restrictions per state law if syncope occurred

— Occupational considerations for pilots, commercial drivers — fitness-for-duty evaluation

— Methimazole is generic and affordable; ensure patient can access pharmacy

— Definitive therapy access (surgery, RAI) varies by insurance — early social work referral for uninsured patients

— Competent patients may refuse RAI/surgery; respect autonomy after documenting risks (recurrent storm, mortality)

Step 3 management: Document capacity assessment at each major decision point; for the post-storm patient choosing definitive therapy, capacity must be reassessed once delirium resolves before consent.

Informed consent in altered mental status:

Pregnancy considerations:

Transition-of-care risks (Step 3 favorite):

Patient safety / "never events":

Mandatory reporting and disability:

Health equity:

Ethics of definitive therapy refusal:

High-Yield Associations and Rapid-Fire Clinical Facts

Board pearl: "Block, Block, Block, Block, Treat" — adrenergic blockade, synthesis blockade, release blockade, peripheral conversion blockade, and treat precipitant. Master this mnemonic and you have 80% of storm management.

Graves triad: diffuse goiter, ophthalmopathy, dermopathy (pretibial myxedema)

Most common precipitant of storm: infection

Most common cause of thyrotoxicosis: Graves disease

First drug given: β-blocker (propranolol — also blocks T4→T3 conversion)

Iodine timing rule: ≥1 hour AFTER thionamide (prevents Jod-Basedow)

Hepatic injury risk: PTU > methimazole (PTU has black box for fulminant hepatic failure)

Teratogenicity: methimazole in 1st trimester (aplasia cutis, choanal atresia) — use PTU

Switch back: PTU → methimazole at 16 weeks gestation

Avoid: aspirin/NSAIDs (displace T4 from TBG, worsen storm)

Apathetic thyrotoxicosis: elderly with AF, weight loss, depression — classic boards stem

Hypokalemic periodic paralysis: young Asian male, sudden flaccid paralysis with thyrotoxicosis

Subacute thyroiditis: tender goiter, post-viral, low RAIU, elevated ESR; treat with NSAIDs + β-blockers

Thyrotoxicosis + low RAIU differential: thyroiditis (subacute, painless, postpartum), factitious, struma ovarii, iodine-induced

Factitious thyrotoxicosis marker: low thyroglobulin (only exogenous source)

Amiodarone-induced thyrotoxicosis type 1: iodine load on autonomous gland — treat with thionamide

AIT type 2: destructive thyroiditis — treat with steroids, no thionamide needed

Distinguishing AIT 1 vs 2: color-flow Doppler — increased in type 1, absent in type 2

Agranulocytosis warning signs: fever, sore throat — STOP drug, do not switch to other thionamide

RAI contraindications: pregnancy, breastfeeding, severe active orbitopathy (pretreat with prednisone)

Post-RAI hypothyroidism: lifelong levothyroxine

Burch–Wartofsky ≥45: highly suggestive of storm

Thyroid storm mortality: 10–30%

Thyroid bruit: virtually pathognomonic for Graves in correct context

Storm + AF + new CHF in elderly: consider thyrotoxic cardiomyopathy — reversible

Cholestyramine: interrupts enterohepatic recirculation of thyroid hormone

Board Question Stem Patterns

A 32-year-old woman with known Graves disease who stopped methimazole 2 weeks ago presents with fever 39.8°C, HR 156 AF, agitation, and a thyroid bruit. Answer: Propranolol IV → PTU PO/NG → 1 hour later SSKI → hydrocortisone → cooling + cultures. Trap: Iodine first (wrong order).

A patient undergoes appendectomy and develops fever, AF, AMS hours postop. History notes weight loss and palpitations. Answer: Thyroid storm (precipitated by surgery in unrecognized hyperthyroidism). Lesson: Preoperative TSH should be checked in symptomatic patients.

A 75-year-old with unexplained weight loss, new AF, depression, and proximal weakness. TSH undetectable. Answer: Apathetic hyperthyroidism — start methimazole and β-blocker.

A 28-year-old at 9 weeks gestation with tachycardia, weight loss, goiter, positive TRAb. Answer: PTU (not methimazole, which is teratogenic). Switch to methimazole at 16 weeks.

A patient on methimazole for 6 weeks presents with fever 39°C and sore throat. Answer: CBC stat, stop methimazole, broad-spectrum antibiotics if neutropenic. Trap: Switch to PTU (wrong — cross-reactivity).

Patient on amiodarone for AF develops thyrotoxicosis. Doppler shows absent vascularity. Answer: Type 2 AIT (destructive) — steroids, not thionamide.

Tender goiter, fever, post-viral, low RAIU. Answer: De Quervain thyroiditis — NSAIDs + propranolol; thionamides ineffective.

Young Asian man with sudden flaccid paralysis, K+ 2.1, suppressed TSH. Answer: Thyrotoxic periodic paralysis — cautious K replacement + propranolol + treat thyrotoxicosis.

Graves patient with moderate active orbitopathy. Answer: Pretreat with prednisone before RAI, or choose surgery.

Patient in storm asks why propranolol is given before PTU. Answer: Adrenergic surge causes most acute morbidity; propranolol controls HR and inhibits T4→T3 conversion immediately.

Board pearl: When the stem highlights medication non-adherence + fever + AF in a known Graves patient — the answer is always thyroid storm.

Stem 1 — Classic Graves storm:

Stem 2 — Post-surgical storm:

Stem 3 — Apathetic thyrotoxicosis:

Stem 4 — Pregnancy 1st trimester:

Stem 5 — Agranulocytosis:

Stem 6 — Amiodarone-induced thyrotoxicosis:

Stem 7 — Subacute thyroiditis mimic:

Stem 8 — Hypokalemic periodic paralysis:

Stem 9 — RAI and orbitopathy:

Stem 10 — Drug selection in storm:

One-Line Recap

Thyroid storm is a clinical diagnosis of decompensated thyrotoxicosis requiring immediate, parallel multi-drug therapy — β-blocker, thionamide, iodine (1 hour after thionamide), and steroid — alongside supportive care and treatment of the precipitant, with ICU admission and definitive therapy planning to follow.

Board pearl: If you remember only one thing — thionamide first, iodine second, separated by ≥1 hour. Reversing this order can precipitate worsening of the very crisis you are treating. Master this and the BWPS criteria and you will recognize and manage every thyroid storm stem the boards throw at you.

Recognition: Fever + tachycardia/AF + AMS + GI/hepatic dysfunction in a thyrotoxic patient. Use BWPS ≥45 as decision threshold but don't wait for it — treat empirically when clinical gestalt fits. Apathetic presentation in the elderly (weight loss, AF, depression) is a common board trap.

Treatment order (memorize this exact sequence): Propranolol → PTU (or methimazole) → wait ≥1 hour → iodine (SSKI/Lugol's) → hydrocortisone → treat precipitant + active cooling with acetaminophen, never aspirin.

Drug selection nuances: PTU in acute storm and 1st trimester pregnancy; methimazole for maintenance and 2nd/3rd trimester. Watch for agranulocytosis (fever, sore throat — stop drug, don't switch) and hepatotoxicity (PTU > methimazole).

Disposition and long-term: ICU admission, endocrine consult, transition to oral regimen as patient improves, discharge with endocrine follow-up in 1–2 weeks, definitive therapy (RAI, thyroidectomy, or prolonged methimazole) within 3–6 months. Counsel on adherence, agranulocytosis warning signs, smoking cessation (orbitopathy), and pregnancy planning.