Thyroid Storm

Thyroid storm is a life-threatening, decompensated state of thyrotoxicosis characterized by multiorgan dysfunction due to severe thyroid hormone excess ^[1]B2b[4]C4. It represents the most extreme form of hyperthyroidism, where the normal compensatory mechanisms of the hypothalamic-pituitary-thyroid axis are overwhelmed, leading to systemic failure.

Also Called / Synonyms: Thyrotoxic crisis, thyrotoxic storm, thyroid crisis. Abbreviation: TS.

Classification and Diagnostic Criteria

Two validated classification schemas provide the framework for diagnosing thyroid storm: the Burch-Wartofsky Point Scale (BWPS) and the Japan Thyroid Association (JTA) criteria ^{[2]D5[4]C4[5]D5[11]D5}. The BWPS integrates fever, central nervous system (CNS) effects, gastrointestinal /hepatic dysfunction, cardiovascular signs (tachycardia, heart failure), and the presence of a precipitant into a total point score; higher scores indicate greater likelihood of thyroid storm ^[11]D5. The JTA criteria define two grades of severity based on combinations of required features, with thyrotoxicosis as a prerequisite ^[4]C4[5]D5.

Note: The JTA criteria also include serum bilirubin >3 mg/dL as a marker of hepatic involvement ^[4]C4[5]D5. The BWPS remains widely used in clinical practice, but its threshold for diagnosis (conventionally ≥45 points) is not explicitly stated in the cited abstracts.

Clinical Significance

Thyroid storm is rare but carries a high mortality: approximately 10-11% in Japanese nationwide surveys ^[4]C4[5]D5. In Germany, case fatality is 1.4% in females ≤60 years but rises to 10.9% in older females, and 16.7% in older males ^[6]B2c. US hospital data show mortality from thyroid storm increasing from 0.62% in 2016 to 4.15% in 2020, underscoring the need for rapid recognition ^[3]B2c. The condition is associated with major adverse cardiovascular events, including acute heart failure and sudden cardiac death ^[3]B2c.

Understanding the underlying thyroid axis physiology and the biochemical cascade of thyroid hormone excess is essential for interpreting these diagnostic criteria and managing the storm; this is discussed in the following section.

Pearl: Mortality remains high (~10-11%) and is increasing in US cohorts; early recognition and application of diagnostic criteria are critical.

From the classification of thyrotoxicosis severity, the transition to thyroid storm represents a breakdown of the physiologic barriers that normally limit the systemic effects of thyroid hormone excess ^[27]D5. Understanding this failure requires tracing the normal hypothalamic-pituitary-thyroid (HPT) axis, identifying the precise node where it breaks, and recognizing the paired hormone pattern that fingerprints the crisis.

Normal Hypothalamic-Pituitary-Thyroid Axis

In the undisturbed state, hypothalamic thyrotropin-releasing hormone (TRH) stimulates pituitary thyrotropin (TSH) secretion, which in turn drives thyroid follicular cells to synthesize and release thyroxine (T4) and triiodothyronine (T3). Circulating T4 and T3 exert negative feedback on both the pituitary and hypothalamus, suppressing TRH and TSH output. This tight loop maintains serum T4 and T3 within narrow reference ranges. Biochemical confirmation of hyperthyroidism, as noted in the prior section, relies on a suppressed TSH with elevated free T4 (FT4) or free T3 (FT3) ^[20]D5.

The Pathogenic Break

The break in this axis occurs at the level of the thyroid gland itself. In Graves’ disease, the most common cause of hyperthyroidism, accounting for approximately 70% of cases ^[20]D5, autoantibodies (TRAb) bind to the TSH receptor and constitutively activate it, driving hormone synthesis independent of TSH feedback. In toxic nodular goiter (16% of cases), autonomously functioning nodules secrete T4 and T3 without TSH stimulation ^[20]D5. The resulting thyroid hormone excess, when extreme, overwhelms the body’s metabolic, thermoregulatory, and cardiovascular compensatory mechanisms, culminating in thyroid storm ^[27]D5.

Key mediators of the systemic decompensation include:

• Enhanced catecholamine sensitivity - Thyrotoxicosis increases myocardial and peripheral responsiveness to catecholamines, predisposing to tachycardia, tachyarrhythmias, and Takotsubo cardiomyopathy ^[22]C4.
• Increased metabolic rate and thermogenesis - Unchecked T3-driven mitochondrial uncoupling and Na+/K+-ATPase activity generate excessive heat, contributing to hyperthermia.
• Cardiovascular stress - Atrial fibrillation is the most common arrhythmic manifestation ^[18]D5; cardiorespiratory failure is the leading cause of death ^[30]C4.
• Neuropsychiatric effects - Agitation, delirium, and seizures may progress to thyrotoxic encephalopathy, as seen in patients with Burch-Wartofsky scores of 70 or higher ^[28]C4.

Biochemical Signature

The laboratory hallmark of thyroid storm is a suppressed TSH (<0.01 mIU/L) with markedly elevated FT4 and FT3 ^[20]D5. In Graves’ disease, TRAb titers are typically >6 U/L and correlate with disease activity ^[20]D5. The severity of the crisis is quantified using the Burch-Wartofsky Point Scale (BWPS), which assigns points for temperature, heart rate, neuropsychiatric symptoms, and precipitating factors; a score of ≥45 is highly suggestive of thyroid storm ^[28]C4.

Precipitating Factors

Thyroid storm rarely arises de novo, it is typically triggered by an event that acutely increases thyroid hormone release or peripheral conversion in a patient with preexisting hyperthyroidism. Common precipitants include infection, surgery, iodine load from contrast agents or amiodarone , and nonadherence to antithyroid drugs ^[27]D5. Drug-induced hyperthyroidism, particularly from immune checkpoint inhibitors (anti-PD-1/PD-L1, anti-CTLA-4), can also progress to storm ^[25]D5.

Mechanism Flowchart

Pearl: The laboratory gatekeeper for thyroid storm is a suppressed TSH with grossly elevated FT4 and FT3; the BWPS (≥45) provides a standardized measure of severity and guides the urgency of ICU-level multimodal therapy ^[28]C4.

Controversies and Guideline Disagreement

From the pathophysiologic cascade of uncontrolled thyroid hormone excess, the clinical consequence is a rare but life-threatening decompensation whose epidemiology reveals striking disparities in incidence and outcome. Thyroid storm incidence varies by region and population: 0.20 per 100,000 per year in Japan ^[4]C4, 0.57 to 0.76 per 100,000 in the United States from 2004-2013 ^[32]B2b, and 1.4 per 100,000 in females and 0.7 in males in Germany ^[6]B2c. Among hospitalized patients, storm accounts for 4.8 to 6.3 per 100,000 admissions ^{[32]B2b[36]D5} and 16.2% of all thyrotoxicosis discharges ^[32]B2b. Hospitalization rates for thyrotoxicosis declined from 7444 to 5424 between 2016 and 2020 in the US, yet mortality rose significantly ^[3]B2c.

Demographically, 72% of cases occur in females ^[6]B2c; the mean age at presentation is 60 years ^[6]B2c. In patients >60 years, incidence triples compared with younger groups, and case fatality rises dramatically: from 1.4% to 10.9% in females and from 1.0% to 16.7% in males ^[6]B2c. Overall storm-associated mortality ranges from 5% to 25% ^[36]D5; in Japan it was 10.7% in the initial survey ^[5]D5 but fell to 5.5% in a prospective registry where guideline adherence was high ^[33]B2b. Mortality is 12-fold higher than in thyrotoxicosis without storm ^[32]B2b.

Risk Factors

Thyroid storm rarely arises de novo; it is almost always precipitated by a trigger in a patient with pre-existing hyperthyroidism, most often Graves' disease (70% of underlying causes) ^[20]D5. The following factors amplify risk:

Infection is the single most common trigger, identified in up to 67% of cases ^[4]C4[41]C4. Other precipitants include surgery, trauma, abrupt discontinuation of antithyroid drugs, emotional stress, iodine load (from amiodarone, iodinated contrast, or seaweed), and exogenous thyroid hormone excess ^[36]D5[45]C4. COVID-19 has been reported to precipitate autoimmune thyroiditis and, rarely, thyroid storm, particularly in women (80% of cases) ^[43]C4.

Etiologic Categories

• Autoimmune: Graves' disease accounts for the vast majority. Genetic variants in CTLA4, HLA-DRA, TSHR, and other loci predispose to hyperthyroidism and may influence storm risk ^[35]B3b.
• Iatrogenic: Amiodarone, tyrosine kinase inhibitors, immune checkpoint inhibitors, and compounded thyroid extracts can cause or exacerbate thyrotoxicosis ^[20]D5[45]C4.
• Infectious: Suppurative thyroiditis (e.g., tuberculosis) can mimic storm ^[42]C4.
• Genetic: GWAS in Taiwan identified 44 novel risk markers at 10 loci, linking hyperthyroidism with stroke risk ^[35]B3b.

No seasonal variation is formally reported, but infection-driven cases may cluster in winter months. The profile of risk factors, modifiable (infection, medication adherence, socioeconomic barriers) and non-modifiable (age, sex, genetics), directly informs prevention and early recognition, setting the stage for the clinical presentation that follows.

Pearl: Graves' disease underlies the majority of storms, and genetic variants in HLA, CTLA4, and TSHR loci confer susceptibility.

From the epidemiology and risk factors, the transition from compensated thyrotoxicosis to thyroid storm is marked by a predictable constellation of organ-specific decompensations that the clinician must recognize at the bedside before laboratory confirmation. The syndrome reflects a breakdown of thermoregulatory, cardiovascular, and neurological compensatory mechanisms, producing a characteristic, though variable, clinical picture.

Presenting Symptoms

The presentation is dominated by a high-output state with exaggerated adrenergic signs. Fever is the cardinal thermoregulatory feature: approximately two‑thirds of patients have a body temperature ≥38.0 °C ^[5]D5. Tachycardia is nearly universal; in definite Japanese cases, 76.2 % had a heart rate ≥130 bpm ^[5]D5. Gastrointestinal or hepatic manifestations occur in 68.3 % of patients ^[5]D5 and include nausea, vomiting, diarrhea, and abdominal pain, often mimicking an acute surgical abdomen. Central nervous system (CNS) symptoms are present in over half of patients: 53.5 % of definite cases have an abnormal Glasgow Coma Scale ( GCS ) score ^[5]D5. The most common combination of features, seen in 15 % of definite cases, is the simultaneous presence of CNS symptoms, fever, tachycardia, and gastrointestinal/hepatic manifestations ^[5]D5.

Neurological Examination Findings

CNS dysfunction is the feature that most reliably distinguishes thyroid storm from severe compensated thyrotoxicosis. In a retrospective cohort comparing storm with hospitalized thyrotoxic patients, altered mentation was the only clinical feature significantly different between groups (P < 0.001) ^[1]B2b. Examination findings span a spectrum from agitation and confusion to stupor and coma. The Japan Coma Scale is abnormal in 62.6 % of definite cases ^[5]D5. Focal neurological signs are absent; when present, consider a structural cause (e.g., subarachnoid hemorrhage , which can co‑occur ^[54]C4). Cranial nerve function is typically intact unless the patient is deeply comatose. Motor examination may reveal tremor or, in the setting of thyrotoxic periodic paralysis , acute flaccid weakness with hypokalemia ^[18]D5.

Phenotypic Variants

Thyroid storm can present in clinically distinct patterns that may delay recognition. The table below summarizes the major variants.

Red Flags

Certain features demand immediate escalation of care because they are independent predictors of mortality.

• Shock (OR 3.90 for death) ^[5]D5
• Disseminated intravascular coagulation (DIC) (OR 3.91) ^[5]D5
• Multiple organ failure (MOF) (OR 9.85) ^[5]D5
• Serum total bilirubin >3 mg/dL, associated with significantly higher mortality and included as a criterion in the Japanese diagnostic system ^[4]C4[5]D5
• Altered mental status, marks the transition from compensated to decompensated disease ^[1]B2b

Atypical Presentations

Thyroid storm may be masked by a concurrent illness. Apathetic thyrotoxicosis presents with depressed consciousness and hypothermia rather than hyperthermia, often in elderly patients, and can be mistaken for sepsis or meningoencephalitis ^[51]C4. Perioperative storm following nonthyroid surgery may manifest solely as refractory tachycardia and delayed awakening, without fever ^[48]C4. Takotsubo cardiomyopathy can be the presenting feature of Graves’ disease, masquerading as acute coronary syndrome ^[50]C4. Chorea due to acute rheumatic fever has been reported to co‑occur with Graves’ disease and simulate storm ^[53]C4. The clinician must maintain a high index of suspicion whenever unexplained tachycardia, altered mentation, or organ dysfunction arises in a patient with known or suspected hyperthyroidism.

Pearl: The absence of fever does not exclude thyroid storm; altered mental status with tachycardia should prompt immediate scoring with the Burch‑Wartofsky scale or Japanese diagnostic criteria, regardless of temperature.

The transition from severe thyrotoxicosis to thyroid storm is a clinical diagnosis, not a biochemical one ^[36]D5. Although the preceding section detailed the protean manifestations, it is the constellation of hyperthermia, tachycardia, and central nervous system dysfunction that should trigger immediate consideration of this diagnosis. No single laboratory threshold defines the transition; the decision to treat aggressively must be made at the bedside before confirmatory tests return.

History and Physical

Key features that should raise suspicion include:

• Central nervous system dysfunction - agitation, confusion, delirium, or coma (the single feature most reliably distinguishing storm from compensated thyrotoxicosis) ^[1]B2b
• Hyperthermia - fever >100.4°F (38°C) ^[1]B2b
• Tachycardia - heart rate >100 beats/min, often >140 beats/min, with atrial fibrillation in up to 50% of cases ^[1]B2b
• Gastrointestinal symptoms - vomiting, diarrhea, abdominal pain, jaundice
• Presence of a precipitating event - infection, surgery, trauma, amiodarone exposure, discontinuation of antithyroid drugs, or recent iodine load ^[36]D5
• Cardiovascular compromise - heart failure, hypotension, pulmonary edema; Takotsubo cardiomyopathy may be a presenting manifestation ^[50]C4
• Profuse sweating and heat intolerance

Diagnostic delay is common. In a 12-year cohort study, median time from symptom onset to diagnosis was 5 days (interquartile range 3.5-7). Older age (1.08 days per 10-year increase; P <.001), initial onset of hyperthyroidism (4.10 days; P <.001), and admission to a non-emergency department (2.76 days; P =.004) were independently associated with longer delays ^[67]B2b. Delayed recognition was linked to increased need for intensive care and organ support ^[67]B2b.

Gold Standard: Clinical Diagnosis with Scoring Systems

No single test confirms thyroid storm. The Burch-Wartofsky Point Scale (BWPS) and the Japanese Thyroid Association (JTA) 2012 criteria are the two most widely used diagnostic tools ^[2]D5. Both are clinical scoring systems designed to standardize the diagnosis and guide treatment urgency.

The BWPS assigns points for:

Higher scores indicate greater probability of storm. A score of 45 or higher is considered highly suggestive of definite storm, 25-44 indicates impending storm, and <25 makes storm unlikely ^[1]B2b. The JTA criteria use a similar approach but define major and minor manifestations with a required combination for diagnosis ^[2]D5.

Important caveat: The BWPS may overdiagnose thyroid storm in patients who lack CNS dysfunction. In the original validation cohort, altered mentation was the only feature that distinguished clinically diagnosed storm from patients who met BWPS criteria but were not treated as storm ^[1]B2b. Therefore, clinical judgment remains paramount; a patient with fever, tachycardia, and a precipitant but a clear sensorium may have severe thyrotoxicosis without storm.

Laboratory Studies

Once thyroid storm is suspected, the following tests should be obtained urgently:

• Thyroid-stimulating hormone (TSH) - suppressed (<0.01 mIU/L) ^[20]D5
• Free thyroxine (FT4) and free triiodothyronine (FT3) - both elevated, often markedly ^[20]D5. The degree of elevation does not correlate with storm severity; patients with minimally elevated hormones can be in storm, and those with very high levels may remain compensated ^[36]D5.
• Complete blood count - to identify infection and assess for agranulocytosis (especially if future antithyroid drug use is planned)
• Electrolytes, liver enzymes, and bilirubin - hepatic dysfunction is common and may be severe ^[61]C4
• Lactate and coagulation profile - evidence of lactic acidosis or disseminated intravascular coagulation indicates multiorgan failure ^[61]C4
• B-type natriuretic peptide (BNP) or NT-proBNP - if heart failure is suspected
• Thyroid peroxidase antibodies, TSH-receptor antibodies - to confirm autoimmune etiology (Graves’ disease) ^[20]D5

Pitfall: Thyroid function tests should not delay treatment. If the clinical picture is convincing, initiate therapy while awaiting results.

Imaging

Imaging is not required for the diagnosis of thyroid storm itself but is essential to identify the underlying cause once the patient is stabilized:

• Thyroid ultrasound - to assess gland size, echogenicity, and nodularity; Graves’ disease shows diffuse hypoechogenicity with increased vascularity ^[20]D5
• Scintigraphy - radioactive iodine uptake scan (e.g., 24-hour uptake) helps distinguish Graves’ disease (high uptake) from destructive thyroiditis (low uptake) ^[20]D5. However, iodine administration is contraindicated in the acute phase if storm is suspected; scintigraphy is reserved for after resolution.
• Cardiac echocardiography - to evaluate left ventricular function, wall motion abnormalities, and valvular disease; Takotsubo cardiomyopathy may be present ^[50]C4

In atypical presentations (e.g., inappropriately normal or high TSH with elevated FT4/FT3), consider a TSH-secreting pituitary adenoma and proceed with pituitary MRI and dynamic testing ^[9]C4.

Diagnostic Algorithm

Step 1: At the bedside, apply the BWPS or JTA criteria. If the score is high or Criterion A is met (e.g., altered mentation with fever >38°C and tachycardia >130 bpm), diagnose thyroid storm and proceed to treatment immediately. Do not wait for lab results.

Step 2: Simultaneously obtain blood for thyroid function tests and other labs. The degree of TSH suppression and FT4/FT3 elevation supports the diagnosis but does not override the clinical assessment.

Step 3: Search for a precipitating event (infection, medication nonadherence, iodine exposure, surgery) and begin treatment of the underlying cause.

Step 4: If the clinical picture is equivocal (e.g., fever and tachycardia from sepsis alone), treat the suspected precipitant first and re-evaluate. If the diagnosis remains uncertain but storm is still a possibility, it is safer to treat for storm than to miss it, given the high mortality of untreated disease ^[36]D5.

Step 5: Once the patient is stabilized, complete the etiologic workup with thyroid ultrasound, antibody testing, and, if indicated, scintigraphy or pituitary imaging.

Pearl: The single most reliable feature distinguishing thyroid storm from compensated thyrotoxicosis is central nervous system dysfunction (altered mentation) ^[1]B2b.

Once the diagnosis of thyroid storm is confirmed, the clinician must immediately grade its severity to guide treatment intensity and predict outcomes. The condition is not binary, it spans a spectrum from suspected to definite storm, and within that, from compensated to decompensated multiorgan failure.

Severity Classification

The Japan Thyroid Association (JTA) criteria define two tiers of severity based on clinical features ^[4]C4. TS1 (definite storm) requires thyrotoxicosis plus at least one combination of CNS manifestations, fever, tachycardia, congestive heart failure, or gastrointestinal /hepatic disturbances. TS2 (suspected storm) uses a less stringent combination of features. In the Japanese nationwide survey, mortality was 11.0% for TS1 and 9.5% for TS2 ^[4]C4. The Burch-Wartofsky Point Scale (BWPS) assigns a weighted score from 0 to 140; a score ≥45 suggests impending storm and ≥25 suggests storm is unlikely ^[5]D5. However, the BWPS has not been prospectively validated, and its correlation with JTA criteria is modest (r² = 0.277) ^[5]D5. Both systems are useful for initial triage, but neither alone captures the full severity of organ failure.

Prognostic Scoring Systems

Beyond diagnostic classification, general critical illness scores stratify risk. The Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment ( SOFA ) scores have been applied to thyroid storm cohorts. In the Japanese survey, mean APACHE II was 10.97 ± 0.35 and SOFA was 2.67 ± 0.47; non-survivors had significantly higher scores (APACHE II 15.00 vs 10.48, p < 0.0001; SOFA 3.12 vs 2.38, p < 0.0001) ^[5]D5. A more recent prospective registry (n = 110) found a median APACHE II of 13, yet mortality fell to 5.5% when the 2016 JTA guidelines were followed, compared with 10.7% historically ^[33]B2b. Among patients with APACHE II ≥12, mortality was 50% when guidelines were not followed vs 4.7% when they were ^[33]B2b.

A dedicated thyroid storm prognostic risk score has been developed from a Thai cohort (n = 115, 30-day mortality 13%) ^[68]B2b. The score incorporates four independently associated variables: male sex (OR 4.34), hypertension (OR 2.54), SOFA ≥2 (OR 9.93), and GCS ≤10 (OR 1.95). Weighted from 0 to 8 points, the score yielded an apparent AUC of 0.81 (bootstrap-validated 0.79) ^[68]B2b. This tool facilitates early identification of patients who may benefit from intensive care unit admission and aggressive therapy.

Risk Factors for Mortality

Multiple studies have identified consistent predictors of death in thyroid storm. The most robust independent factors are shock (OR 3.90), disseminated intravascular coagulation (OR 3.91), and multiple organ failure (OR 9.85) ^[5]D5. Early cardiogenic shock within 48 hours of ICU admission carries an even higher risk (OR 9.43) ^[12]B2b. Age >60 years markedly increases case fatality: in a German claims analysis, mortality was 16.7% in men >60 years and 10.9% in women >60 years, compared with <2% in younger patients ^[6]B2c. US data show an uptrend in mortality from thyroid storm, rising from 0.62% in 2016 to 4.15% in 2020, along with increased rates of major adverse cardiovascular events ^[3]B2c.

Other factors that worsen prognosis include lower body mass index, absence of fever ≥38°C (suggesting blunted response), higher GCS (oddly protective), elevated BUN, and left ventricular dilatation with high BNP ^{[33]B2b[5]D5[70]C4}. Diagnostic delay, especially in older patients with initial-onset hyperthyroidism, is associated with greater need for organ support ^[67]B2b.

Pearl: The JTA two-tier system (TS1/TS2) and the Burch-Wartofsky scale are complementary for diagnosis, but the strongest predictors of mortality are shock, DIC, and MOF, use the APACHE II or the new prognostic risk score to guide ICU triage and treatment intensity, as adherence to the 2016 JTA guidelines reduces mortality from 50% to 4.7% in high-risk patients ^[33]B2b.

Once the diagnosis of thyroid storm is confirmed by validated scoring tools, management shifts from identification to simultaneous, time-critical intervention. The core principle is to block thyroid hormone synthesis, inhibit hormone release, counteract peripheral adrenergic effects, and provide supportive care, all within the first hours of recognition ^{[1]B2b[2]D5[36]D5}.

Step 1: Immediate Resuscitation and Precipitant Identification

Secure the airway, optimize oxygenation, and establish intravenous access. Continuous cardiac monitoring is essential, as tachyarrhythmia and heart failure are common. Fever >100.4 °F requires active cooling (acetaminophen, cooling blankets); avoid aspirin , which displaces thyroid hormone from binding proteins. Concurrently, identify the precipitating event, most often infection, surgery, trauma, iodine exposure, or medication nonadherence, and treat it directly ^[1]B2b[36]D5.

Step 2: Beta-Blockade

Beta-blockers are the first pharmacologic priority to control heart rate and reduce myocardial oxygen demand. They also partially suppress peripheral T4-to-T3 conversion. All but one patient in a six-year cohort received beta-blockade within 24 hours of diagnosis ^[1]B2b. The choice of agent is guided by availability and tolerability; propranolol has been used traditionally, but esmolol or metoprolol are alternatives when heart rate remains elevated ^[36]D5[40]D5.

Step 3: Thionamides

Antithyroid drugs block new hormone synthesis. Methimazole is the preferred agent because of its once-daily dosing and lower hepatotoxicity risk compared with propylthiouracil . The 2024 registry-based study by Duntas and Zarkovic reported that most patients received methimazole, and timely administration was linked to lower fatality rates ^[2]D5. A loading dose is given, followed by a maintenance dose; exact dosing is per institutional protocol and should be continued until hormone levels normalize ^[2]D5[36]D5.

Step 4: Corticosteroids

Hydrocortisone or dexamethasone reduces peripheral conversion of T4 to T3, supports adrenal function (which may be compromised in critical illness), and has anti-inflammatory effects. The combination of glucocorticoids with thionamides and beta-blockade was administered to all but one patient within 24 hours in the Angell et al. cohort ^[1]B2b.

Step 5: Iodine Administration

Iodine ( potassium iodide or Lugol's solution ) inhibits the release of preformed thyroid hormone via the Wolff-Chaikoff effect. Crucially, iodine must be given at least one hour after the first dose of thionamide to avoid providing substrate for new hormone synthesis. In a large Japanese database study, potassium iodide use within 2 days of admission was associated with lower in-hospital mortality in patients with Graves' disease (OR 0.46; 95% CI 0.25-0.88) ^[63]B2b. The 2024 registry study also noted that timely administration of methimazole plus potassium iodide correlated with improved outcomes ^[2]D5.

Step 6: Refractory Cases and Therapeutic Plasma Exchange

When standard therapy fails or rapid preoperative normalization is needed, therapeutic plasma exchange (TPE) can rapidly lower circulating thyroid hormone levels. A case series of six patients with severe thyrotoxicosis or thyroid storm reported a mean fT4 reduction of 51.7% (95% CI 1.1-4.5 ng/dL; P =.01) after a mean of 5.5 TPE sessions, with a preoperative fT4 target of 2.5-3.3 ng/dL suggested as a bridge to thyroidectomy ^[60]C4. Iopanoic acid , an oral iodinated contrast agent, has also been used in refractory cases; a retrospective study demonstrated a mean 55% decrease in free T3 levels with normalization achieved in all 12 patients prior to uneventful thyroidectomy ^[72]C4.

Step 7: Transition to Definitive Therapy

Once the patient stabilizes and thyroid hormone levels begin to normalize, the clinician should plan definitive therapy for the underlying hyperthyroidism, radioactive iodine, thyroidectomy, or long-term antithyroid drugs. The choice depends on patient preference, goiter size, presence of ophthalmopathy, and surgical risk. The transition to definitive therapy is covered in the next section.

Pearl: Simultaneous administration of a thionamide, beta-blocker, corticosteroid, and iodine (after thionamide) is the cornerstone of initial management; adherence to published guidelines reduces mortality, and TPE should be considered early for refractory cases or as a bridge to surgery ^{[1]B2b[2]D5[60]C4[63]B2b}.

Once the acute hypermetabolic state is controlled and the patient is hemodynamically stable, the clinician must select a definitive long-term strategy to prevent recurrence of thyroid storm and maintain sustained euthyroidism. The choice among continued antithyroid drugs (ATDs), radioactive iodine (RAI) ablation, thyroidectomy , and emerging therapies such as radiofrequency ablation ( RFA ) is guided by the underlying etiology, patient preference, comorbidities, and access to high-volume surgical centers ^{[5]D5[20]D5[40]D5}.

Step 1: Selecting the Long-term Strategy

For Graves' disease, the most common cause of thyroid storm, long-term ATD therapy (12-18 months initially) remains first-line in many regions, but recurrence after discontinuation occurs in approximately 50% of patients ^[20]D5. The ATA 2016 guideline (referenced in ^[5]D5) and the JTA 2016 guideline (referenced in ^[5]D5) both recommend definitive therapy with RAI or surgery for patients who fail ATD, have contraindications, or develop thyroid storm. The JTA nationwide survey found that 78% of patients with thyroid storm received methimazole (MMI) during the acute phase, but definitive therapy was pursued in most survivors ^[5]D5.

Step 2: Antithyroid Drugs as Long-term Therapy

For patients who prefer medical management or are poor surgical candidates, long-term ATD therapy (e.g., MMI 5-15 mg daily) is feasible and associated with fewer recurrences when continued for 5-10 years (15% recurrence vs. 50% after 12-18 months) ^[20]D5. The JTA guidelines recommend MMI as the first-choice ATD for compensated Graves' disease, citing a randomized prospective study showing MMI 30 mg/day normalized thyroid hormones more rapidly than PTU 300 mg/day, with a lower incidence of adverse effects ^[5]D5. For patients with thyroid storm, both MMI and PTU are acceptable; the nationwide survey found no significant difference in mortality or severity between the two ^[5]D5. PTU may be preferred when elevated T3 is the dominant feature due to its inhibition of type I deiodinase at doses ≥400 mg/day ^[5]D5.

Step 3: Radioactive Iodine Ablation

RAI is a definitive therapy for Graves' disease and toxic nodular goiter. It is contraindicated in pregnancy and lactation, and in patients with moderate-to-severe Graves' ophthalmopathy ^[20]D5. Before RAI in patients with a history of thyroid storm, achieving euthyroidism with ATDs is recommended to minimize the risk of radiation-induced thyroiditis and storm recurrence. A retrospective cohort study found that lithium carbonate bridging (target serum 0.6-1.0 mmol/L) from ATD withdrawal until 7 days post-RAI was associated with a higher euthyroidism rate at 6 months (30.4% vs. 13.0%, P = 0.009) and a lower hypothyroidism rate (54.3% vs. 77.0%, P = 0.005) compared to standard care, with no cases of thyroid storm in the lithium group vs. 3.0% in controls ^[76]B2b. The same study reported that pre-RAI FT3 was a key modifiable risk factor for treatment failure (adjusted OR 1.55 per 5 pmol/L increase, 95% CI 1.15-2.09, P = 0.004) ^[76]B2b.

Step 4: Thyroidectomy, Timing and Safety

Total thyroidectomy provides rapid and definitive control of hyperthyroidism. The 2016 ATA guidelines recommended that patients be euthyroid before surgery, but this recommendation was based on low-quality evidence ^[64]B2b. A retrospective cohort study of 275 patients (51.3% uncontrolled at surgery) found that uncontrolled patients had higher rates of temporary hypocalcemia (13.4% vs. 4.7%, P = 0.013) and longer operative times, but no patient in either group developed thyroid storm ^[64]B2b. A separate study of 242 patients (23.1% hyperthyroid at surgery) reported that hyperthyroid patients had higher intraoperative heart rates and greater need for antihypertensives, but no difference in adverse outcomes ^[73]B2b. These data suggest that thyroidectomy can be performed safely in actively thyrotoxic patients when high-volume endocrine surgeons are available, without requiring biochemical euthyroidism ^{[64]B2b[73]B2b}.

Step 5: Emerging and Bridging Therapies

Radiofrequency Ablation (RFA): In a prospective study of 30 patients with relapsed Graves' disease and small thyroid glands (median volume 23 mL), single-session RFA achieved disease remission in 60.0% at 12 months and 56.7% at 24 months ^[74]C4. Total thyroid volume <20 mL was associated with 100% remission (vs. 35% for ≥20 mL, P = 0.007), and no case of thyroid storm occurred ^[74]C4. RFA may be considered for selected patients who decline surgery or RAI.

Iopanoic Acid (IOPA): For patients with refractory thyrotoxicosis, IOPA (an oral iodinated contrast agent) can rapidly lower FT3 levels (mean 55% decrease, SEM 4.5%) without significant changes in FT4, allowing safe transition to thyroidectomy ^[72]C4. In a case series of 12 patients, 11 proceeded to uneventful surgery with no attributable side effects ^[72]C4.

Therapeutic Plasma Exchange (TPE): In patients with severe thyrotoxicosis or thyroid storm refractory to medical therapy, TPE can be used as a bridge to thyroidectomy. A case series reported a mean FT4 reduction of 51.7% (95% CI 1.1-4.5 ng/dL) after 5.5 treatments, with a preoperative FT4 goal of 2.5-3.3 ng/dL proposed ^[60]C4.

Step 6: Treat-to-Target Monitoring

After definitive therapy, the goal is sustained euthyroidism. For RAI, thyroid function tests (TSH, FT4, FT3) should be monitored every 4-6 weeks until stable, then annually. For thyroidectomy, levothyroxine replacement is initiated postoperatively, with dose titration to a target TSH 0.5-2.5 mIU/L. For ATD therapy, the dose is adjusted to maintain TSH in the normal range while minimizing adverse effects. The JTA guidelines emphasize that serum FT3 may be disproportionately low in severe illness, so FT4 and TSH should guide therapy ^[5]D5.

Controversies and Guideline Disagreement

Pearl: For patients with a history of thyroid storm, definitive therapy (thyroidectomy or RAI) should be strongly considered once the acute crisis resolves; if surgery is chosen, delaying the procedure for euthyroidism is not mandatory in experienced hands, and lithium or iopanoic acid bridging can optimize outcomes before RAI or surgery.

The long-term management of hyperthyroidism, whether by medication, radioiodine, or surgery, was forged through decades of experience with the acute crisis of thyroid storm. Before the introduction of specific antithyroid therapy, mortality approached 100% in frank thyroid storm. The modern era of treatment began in the 1940s with the thionamides, which block thyroid peroxidase and inhibit hormone synthesis. Propylthiouracil and methimazole remain the backbone of acute therapy, though their history is marked by rare but serious adverse effects: methimazole can cause agranulocytosis and, as documented in case reports, parotitis, a phenomenon that resolves with dose reduction ^[56]C4.

Beta-Blockade and the Advent of Multimodal Therapy

In the 1960s, the recognition that many manifestations of thyrotoxicosis are mediated by adrenergic overactivity led to the introduction of beta-blockers. Propranolol, in particular, became standard both for symptom control and for its ability to inhibit peripheral T4-to-T3 conversion. The landmark addition of iodine (Lugol's solution, introduced as early as the 1920s but now reserved for post-thionamide administration) exploits the Wolff-Chaikoff effect to acutely block hormone release. Glucocorticoids were added in the 1970s to reduce peripheral T4 conversion and to treat relative adrenal insufficiency. However, contemporary evidence questions the routine use of glucocorticoids: studies have found that routine use does not improve survival in thyroid storm patients, suggesting that clinicians should individualize therapy, weighing the risk of infection and hyperglycemia ^[82]C4.

The Paradigm Shift in Surgical Timing

For decades, guidelines mandated that patients be rendered euthyroid before thyroidectomy , based on the fear that surgery would precipitate storm. The 2016 American Thyroid Association guidelines reinforced this recommendation, albeit on low-quality evidence. A landmark retrospective cohort study of 275 patients, the largest to date, directly challenged this dogma: uncontrolled hyperthyroid patients (51.3% of the cohort) underwent thyroidectomy with no cases of perioperative thyroid storm, and complication rates were similar to controlled patients except for a higher rate of temporary hypocalcemia (13.4% vs. 4.7%, p = 0.013) ^[64]B2b. This evidence has shifted practice toward earlier, safer surgical intervention in actively thyrotoxic patients.

Rescue Therapies: Plasmapheresis and ECMO

When medical therapy fails, plasma exchange rapidly removes circulating thyroid hormone. In a case of exogenous thyroid storm from compounded thyroid extract, plasmapheresis for two consecutive days resulted in dramatic clinical improvement and normalization of thyroid function ^[45]C4. For patients with refractory cardiogenic shock or respiratory failure, extracorporeal membrane oxygenation (ECMO) has emerged as a life-saving bridge. In case series, ECMO survival in thyroid storm is reported at 85.2% ^[49]C4. Both venoarterial (VA) and venovenous (VV) ECMO have been used successfully; the choice depends on the predominant organ failure. A recent report describes thyroidectomy performed under general anesthesia while on VV ECMO support, demonstrating that even complex surgical rescue is feasible with appropriate anesthetic management ^[49]C4.

Emerging Definitive Treatment: Radiofrequency Ablation

Radiofrequency ablation ( RFA ) of the thyroid gland is a novel, minimally invasive definitive treatment for persistent or relapsed Graves' disease. In a prospective study of 30 selected patients, single-session RFA achieved disease remission (euthyroid or hypothyroid without antithyroid drugs) in 56.7% at 24 months, with no vocal cord palsy, skin burn, hematoma, or thyroid storm ^[74]C4. Smaller total thyroid volume (<20 mL) was a favorable predictor, with 100% remission in that subgroup ^[74]C4. A pilot study confirmed similar safety and efficacy, with remission rates of 79% at 6 months and 73.3% at 12 months ^[77]C4. RFA offers an alternative to surgery or radioiodine for patients who decline or cannot undergo conventional definitive therapy.

Pearl: The evolution of thyroid storm treatment has been a shift from a single-agent approach to a coordinated, multi-drug, multi-modality strategy, and the most recent evidence now permits safe thyroidectomy even in uncontrolled hyperthyroidism, overturning a decades-old contraindication ^[64]B2b.

Controversies and Guideline Disagreement

The preceding section documented the evolution of treatment from antithyroid drugs to multimodal ICU care. Yet thyroid storm does not occur in an endocrine vacuum - it can herald underlying multiglandular disease or perturb adjacent endocrine axes, requiring syndromic screening and cross-axis surveillance.

Genetic Syndromes and Pituitary Causes

Rare causes of hyperthyroidism that can precipitate storm include TSH-secreting pituitary adenoma s (TSHomas). In a cohort of 12 patients with TSHomas, the mean diagnostic delay was 42.5 months, and longer delay correlated with larger tumors (17.9±3.6 mm vs 9.8±1.0 mm; p=0.004) ^[9]C4. No patient in that series experienced thyroid storm, but the hyperthyroidism can be severe. The key biochemical clue: inappropriately normal or elevated TSH in the presence of elevated free T3 and T4. Refer endocrinology before thyroid ablation - surgery is first-line for TSHomas ^[9]C4. Other genetic syndromes (e.g., McCune-Albright syndrome, familial non-autoimmune hyperthyroidism) are theoretical triggers but lack published storm series.

Co-Axis Effects: Diabetes and Pancreas

Thyroid storm frequently co-occurs with diabetic ketoacidosis (DKA). A case of simultaneous DKA and storm in a 20-year-old male with T1DM and hyperthyroidism illustrates the diagnostic challenge: overlapping symptoms of hyperglycemia, vomiting, and altered mental status ^[86]C4. Conversely, methimazole therapy can induce insulin autoimmune syndrome (IAS) with hypoglycemic coma; one patient developed thyroid storm during IAS treatment ^[89]C4. Clinicians should check glucose, ketones, and insulin autoantibodies in storm patients with unexplained hypoglycemia or hyperglycemia.

Cardiovascular Axis: Takotsubo and ACS

Thyrotoxicosis is a recognized trigger of Takotsubo cardiomyopathy (stress-induced cardiomyopathy). In a case series, 12 cases of Takotsubo associated with thyrotoxicosis were reported, with one presenting as thyroid storm ^[50]C4. Chronic high-altitude hypoxia may further potentiate sympathetic activity and catecholamine responsiveness, as seen in a case of Takotsubo with apical thrombosis ^[22]C4. Additionally, acute coronary syndrome (ACS) can be precipitated by thyrotoxicosis: in 35 cases, 60% presented with STEMI, and thyroid storm was associated with malignant ventricular arrhythmias or sudden cardiac death in ~20% ^[38]B2a. Obtain ECG, troponin, and echocardiography in all storm patients with chest pain or dyspnea.

Immune Activation and Other Axes

Thyroid storm is associated with a marked inflammatory response. A case of storm with multiple organ failure and DIC showed a markedly elevated soluble interleukin-2 receptor level (7,416 U/mL, reference range 135-483), reflecting generalized immune activation ^[92]C4. COVID-19 infection can trigger storm, with cases of thyrotoxic crisis requiring ICU ^[43]C4[85]C4. This suggests that any severe infection in a patient with underlying hyperthyroidism can precipitate storm and cause multi-organ dysfunction.

Syndromic Screening

When thyroid storm is refractory or recurrent, consider screening for underlying genetic syndromes. Unexplained hypercalcemia , pituitary tumor, or family history of endocrine tumors should prompt evaluation for MEN1 . Café-au-lait spots or fibrous dysplasia suggest McCune-Albright syndrome . However, evidence for routine screening is limited; clinical judgment is required.

Pearl: In any patient with thyroid storm and a non-suppressed TSH, suspect a TSH-secreting pituitary adenoma and obtain pituitary imaging before considering thyroid ablation.

The preceding section detailed the genetic and syndromic contexts of hyperthyroidism; once thyroid storm has declared itself, multisystem organ damage determines both short- and long-term outcomes. In-hospital mortality remains substantial, ranging from 5.5% at 30 days in a prospective Japanese registry ^[33]B2b to 10.7-11% in earlier nationwide surveys ^[5]D5[4]C4, and up to 25% in retrospective series ^[36]D5. The 12-fold higher mortality compared with thyrotoxicosis without storm (1.2-3.6% vs 0.1-0.4%) underscores the urgency of aggressive intervention ^[32]B2b.

Acute Complications

Multiple organ failure (MOF) is the most common cause of death, followed by congestive heart failure, respiratory failure, arrhythmia, disseminated intravascular coagulation, gastrointestinal perforation, hypoxic brain syndrome, and sepsis ^[5]D5[4]C4. Among survivors, prolonged ICU stays and ventilator dependence are frequent ^[1]B2b.

Cardiovascular. Atrial fibrillation is the most common cardiovascular manifestation of thyrotoxicosis and may persist after euthyroidism is restored ^[18]D5. Takotsubo (stress-induced) cardiomyopathy can present as the initial manifestation of thyroid storm, mimicking acute coronary syndrome ^[50]C4. Lower left ventricular ejection fraction and shock at presentation are independently associated with 30-day mortality ^[33]B2b.

Respiratory and Neurologic. Respiratory failure necessitating mechanical ventilation occurred in a significant proportion of storm patients ^[1]B2b. Central nervous system dysfunction, including agitation, confusion, delirium, and seizures, is a hallmark of storm and, when present, should prompt immediate escalation of therapy ^[1]B2b[28]C4. Hypoxic brain injury is a recognized long-term sequela ^[4]C4.

Hepatic, GI, and Hematologic. Jaundice (serum bilirubin >3 mg/dL) is a criterion for storm diagnosis and reflects hepatic congestion and dysfunction ^[4]C4. DIC, GI perforation, and sepsis contribute to late mortality ^[4]C4.

Long-term Sequelae

Survivors of thyroid storm carry an increased long-term mortality risk, likely driven by persistent cardiovascular damage and complications of underlying hyperthyroidism ^[20]D5. Delayed diagnosis (median time to diagnosis 5 days) is associated with greater need for intensive care and organ support, emphasizing the importance of early recognition ^[67]B2b.

Prevention and Surveillance

Adherence to the 2016 Japanese Thyroid Association guidelines reduced 30-day mortality when followed (4.7% vs 50% in patients with APACHE II ≥12 when guidelines were not followed) ^[33]B2b. Prompt administration of potassium iodide within 2 days of admission was associated with lower in-hospital mortality in patients with Graves’ disease (OR 0.46, 95% CI 0.25-0.88) ^[63]B2b.

Pearl: The most common cause of death in thyroid storm is multiple organ failure, not arrhythmia, so the clinician must focus on rapid normalization of thyroid hormone levels and comprehensive organ support, not just rate control.

The high mortality of thyroid storm, 11% in the Japanese nationwide survey and 17% in ICU cohorts, underscores the urgency of prevention through early detection and definitive treatment of hyperthyroidism ^[4]C4[12]B2b. Without prompt recognition and aggressive therapy, the natural history is rapid decompensation: multiple organ failure, cardiogenic shock , and death within days. With modern management , outcomes have improved but remain sobering.

Prognosis and Predictors of Mortality

The prospective multicenter registry from Japan reported a 30-day mortality of 5.5%, approximately half the 10.7% rate from the earlier nationwide survey, despite higher disease severity (median APACHE II score 13 vs 10) ^[33]B2b. Adherence to the 2016 Japanese guidelines was associated with significantly lower mortality: among patients with APACHE II ≥12, mortality was 4.7% when guidelines were followed versus 50% when they were not ^[33]B2b. In the French ICU cohort, in-ICU mortality was 17% and 6-month mortality 22%; independent predictors were early cardiogenic shock (OR 9.43, 95% CI 1.77-50.12) and higher SOFA score ^[12]B2b. Coma complicating thyroid storm carries a 38% overall mortality, though this fell from 70% (1935-1977) to 11% (1978-2019) with modern intensive care ^[102]D5.

Natural History Under Treatment

With timely administration of antithyroid drugs (methimazole), potassium iodide, β-blockers, and corticosteroids, thyroid hormone levels begin to fall within 24-48 hours, and clinical improvement typically follows over 3-7 days ^[2]D5[33]B2b. The Japanese registry found that timely administration of methimazole and potassium iodide was linked to lower fatality rates ^[2]D5. However, even with optimal therapy, 38% of ICU patients developed cardiogenic shock within 48 hours, and 22% died within 6 months ^[12]B2b. For patients who survive the acute episode, definitive treatment of the underlying hyperthyroidism (radioiodine, thyroidectomy , or long-term ATD) is essential to prevent recurrence.

Prevention Strategies

Early diagnosis and treatment of hyperthyroidism is the cornerstone. Graves' disease, the most common cause, recurs in approximately 50% of patients after a 12-18 month course of ATD; long-term ATD (5-10 years) reduces recurrence to 15% ^[20]D5. Definitive therapy with radioiodine or thyroidectomy eliminates the risk of storm from the underlying disease. Radiofrequency ablation is emerging as a safe alternative for selected patients with relapsed Graves' disease, achieving 56.7% remission at 24 months ^[74]C4.

Preoperative optimization is mandatory. Elective surgery should be postponed until the patient is euthyroid ^[93]B2a. For urgent surgery or ATD intolerance, second-line pharmacotherapy (corticosteroids, Lugol's iodine, cholestyramine, lithium) and/or therapeutic plasma exchange (TPE) effectively reduce thyroid hormone levels; in a systematic review, no perioperative thyroid storm occurred despite incomplete normalization of hormones ^[93]B2a.

Avoidance of triggers includes prompt treatment of infection, avoidance of iodine-containing agents ( amiodarone , contrast) in susceptible patients, and ensuring medication adherence. Immune checkpoint inhibitors can precipitate thyroid storm; baseline and periodic thyroid function monitoring is recommended during therapy ^[98]D5. COVID-19 infection has been reported to trigger both new-onset Graves' disease and thyroid storm; clinicians should maintain a low threshold for thyroid testing in hyperthyroid patients with SARS-CoV-2 ^[43]C4[99]C4.

Screening for hyperthyroidism in asymptomatic populations is not routinely recommended. In pregnancy, universal screening increases diagnosis and treatment of hypothyroidism but does not clearly improve maternal or infant outcomes ^[65]A1a. For first-degree relatives of patients with Graves' disease, measurement of TSH and TPO antibodies may identify subclinical disease, though evidence for improved outcomes is lacking ^[20]D5.

Pearl: The single most effective prevention is achieving and maintaining euthyroidism in all patients with hyperthyroidism, whether by ATD, radioiodine, or surgery, before the cascade of organ failure begins.

While prognosis and prevention strategies apply broadly, several populations require tailored approaches due to physiologic differences that alter presentation, diagnosis, and management .

Pediatrics

Thyroid storm in children, though rare, presents distinct challenges. In a systematic review of 45 pediatric cases (mean age 11.25 years), the most common features were sinus tachycardia (86.7%) and fever (64%), followed by altered mental status (46%) and diarrhea (31%) ^[41]C4. Graves' disease was the most common etiology, and infection the most frequent trigger ^[41]C4. Seizures occur in approximately 19% of pediatric thyroid storm cases, substantially higher than the 4% in adults, with infants and children affected more often than adolescents ^[16]C4. Importantly, seizures do not necessarily predict poor prognosis; 15 of 16 patients with seizures recovered without persistent neurological complications ^[16]C4. However, the Burch-Wartofsky Point Scale may overestimate severity in children because it assigns 30 points for seizures, and a child's higher baseline heart rate inflates the score ^[16]C4. No pediatric-specific diagnostic criteria exist; management follows adult protocols with weight-based dosing of antithyroid drugs, beta-blockers, and corticosteroids. One case series reported a death in a 13-year-old girl presenting with loss of consciousness and shock ^[109]C4, emphasizing the need for prompt ICU care.

Pregnancy

Pregnancy complicates the diagnosis and management of thyroid storm. The hyperdynamic state can mask thyrotoxicosis, and thyroid storm in pregnancy carries a higher rate of heart failure ^[104]D5. When superimposed on gestational hypertension , diagnosis is particularly challenging due to overlapping symptoms ^[107]C4. A unique cause is hCG-mediated hyperthyroidism from gestational trophoblastic disease, including partial hydatidiform mole ^[106]C4 and choriocarcinoma ^[105]C4; thyroid function normalizes after treatment of the trophoblastic tissue ^{[106]C4[105]C4}.

Universal screening for thyroid dysfunction in pregnancy increases diagnosis of hyperthyroidism (RR 4.50, 95% CI 0.97 to 20.82) but does not clearly improve maternal or infant outcomes ^[65]A1a; case finding based on risk factors remains standard. Management of thyroid storm in pregnancy uses antithyroid drugs (propylthiouracil preferred in first trimester, methimazole thereafter), beta-blockers, and corticosteroids. If medical therapy fails, thyroidectomy can be performed safely even before euthyroidism is achieved, with no increase in thyroid storm risk ^[64]B2b. For refractory cases, therapeutic plasma exchange or iopanoic acid may be used ^{[93]B2a[72]C4}. Delivery planning requires a multidisciplinary team; emergency caesarean section may be necessary ^[107]C4. Antithyroid medications are compatible with breastfeeding .

Elderly

Older adults often present with "apathetic" thyrotoxicosis, lethargy, weakness, and depression rather than hyperadrenergic features, delaying diagnosis. Comorbidities such as atrial fibrillation and heart failure are common and may be exacerbated. Beta-blockers should be started at lower doses (e.g., propranolol 10-20 mg every 6 hours) and titrated cautiously. Antithyroid drug dosing is similar to younger adults but requires close monitoring for adverse effects.

Immunocompromised

Immunocompromised patients are at increased risk for infections, a common thyroid storm trigger. Atypical presentations may occur due to blunted inflammatory responses. Management follows standard protocols with emphasis on infection source control and review of drug interactions.

Pearl: In pediatric thyroid storm, seizures are common and do not necessarily portend poor outcome, but the Burch-Wartofsky scale may overestimate severity; in pregnancy, consider hCG-mediated hyperthyroidism from gestational trophoblastic disease as a reversible cause.