Thyroid storm is a rare but extremely life-threatening endocrine emergency caused by sudden and severe worsening of thyrotoxicosis.It is characterized not simply by very high thyroid hormone levels, but by systemic decompensation — failure of multiple organs due to excessive metabolic stimulation by thyroid hormones.

Mortality remains high (10–30%) even with treatment, therefore early recognition and immediate aggressive management are critical.

Pathophysiology

In thyrotoxicosis, circulating T3 and T4 increase metabolic activity. In thyroid storm, a precipitating stress causes:

• Massive increase in adrenergic activity

• Increased tissue sensitivity to catecholamines

• Hypermetabolism → heat production

• Cardiovascular collapse

• CNS dysfunction

• Hepatic failure

Importantly, hormone levels may be only slightly higher than in uncomplicated hyperthyroidism — the danger is the body’s inability to compensate.

Risk Factors

Patients at highest risk include:

• Untreated or poorly controlled hyperthyroidism (especially Graves’ disease)

• Elderly patients

• Previous thyroid surgery

• Severe systemic illness

• Poor medication adherence

Triggers (Precipitating Factors)

Thyroid storm usually occurs after a stressor in a thyrotoxic patient:

• Acute infections (most common)

• Thyroid or non-thyroid surgery

• Trauma

• Myocardial infarction

• Diabetic ketoacidosis

• Iodinated contrast dye exposure

• External beam radiation therapy

• Childbirth

• Abrupt withdrawal of antithyroid drugs

It should be suspected in any severely ill patient with known thyrotoxicosis and a recent precipitating event.

Signs and Symptoms

Cardiovascular

• Severe tachycardia (>140 bpm)

• Atrial fibrillation or other arrhythmias

• Congestive heart failure

• Hypotension → shock

Temperature

• Hyperpyrexia (often > 39–41°C)

Central Nervous System

• Agitation

• Delirium

• Psychosis

• Confusion

• Seizures

• Stupor or coma

Gastrointestinal / Hepatic

• Nausea and vomiting

• Profuse diarrhoea

• Abdominal pain

• Jaundice

• Acute hepatic failure

Others

• Sweating

• Tremor

• Dehydration

• Weight loss

Diagnostic Criteria

Diagnosis is clinical — do NOT wait for lab confirmation.

Burch-Wartofsky Point Scale (BWPS)

Used to support diagnosis:

Score:

• ≥45 → Thyroid storm highly likely

• 25–44 → Impending storm

• <25 → Unlikely

Investigations

(Do not delay treatment)

Laboratory

• ↓ TSH (suppressed)

• ↑ Free T4 / T3

• Hyperglycaemia

• Hypercalcaemia

• Elevated liver enzymes

• Leukocytosis

Supportive tests

• ECG (arrhythmias)

• ABG (metabolic acidosis)

• Chest X-ray (infection/heart failure)

• Blood cultures if infection suspected

Management

Medical emergency — treat in ICU

Management is simultaneous and multimodal.

Non-Pharmacological Management

1. Airway and oxygen support

2. Aggressive IV fluid resuscitation

3. Cooling measures:

   • Cooling blankets

   • Ice packs

   • Acetaminophen (avoid aspirin — increases free T4)

4. Treat precipitating cause (antibiotics, surgery complications)

5. Cardiac monitoring

6. Mechanical ventilation if needed

Pharmacological Management

Treat in the correct sequence:

1. Beta-adrenergic Blockade (First Step)

Controls adrenergic symptoms

• Propranolol IV or oral (preferred)

• Esmolol infusion if unstable

2. Antithyroid Drugs (Block Hormone Production)

Propylthiouracil (PTU) preferred over carbimazole/methimazoleReason: PTU blocks peripheral T4 → T3 conversion

3. Iodine Therapy (Block Hormone Release)

Give 1 hour AFTER PTU

• Lugol’s iodine

• Potassium iodide

(Prevents release of preformed hormone)

4. Corticosteroids

• Hydrocortisone IV

Benefits:

• Prevent adrenal insufficiency

• Reduce T4 → T3 conversion

5. Additional Therapies

• Cholestyramine (reduces hormone recycling)

• Antipyretics (acetaminophen)

• Treat arrhythmias and heart failure

Treatment Summary Sequence

1. Beta blocker

2. PTU

3. Iodine (after PTU)

4. Steroid

5. Supportive care + treat cause

Monitoring

All patients require ICU care with:

• Continuous cardiac monitoring

• Temperature monitoring

• Electrolytes and glucose

• Liver function tests

• Fluid balance

Prevention

Preventable in most cases.

• Adequate treatment of hyperthyroidism

• Do NOT stop antithyroid drugs abruptly

• Pre-operative preparation before thyroid surgery

• Beta-blocker and thionamide before iodinated contrast

• Early treatment of infections in thyrotoxic patients

• Careful monitoring during pregnancy and postpartum

Key Clinical Pearl

Early recognition and immediate treatment save life.