- It is an exaggerated presentation of thyrotoxicosis.
- It comes with sudden multisystem involvement.
- The mortality associated with thyroid storm is estimated to be 8-25% despite modern advancements in its treatment and supportive measures
Precipitants of Thyroid Storm
- Untreated/Undertreated Disease: Medication non-compliance. Abrupt discontinuation of antithyroid medicine
- Physical Stress: Trauma, surgery (thyroid or non-thyroid), myocardial infarction/ischemia.
- Acute illness: diabetic ketoacidosis, acute myocardial infarction, cardiovascular accident, cardiac failure, drug reaction
- Infections: General infections, diabetic ketoacidosis/hyperosmolar nonketotic coma.
- Iodine Exposure: Iodinated contrast in susceptible patients.
- Ingestion: Excess thyroid hormone.
Pathophysiology
- Hormone Dynamics: T4 is deiodinated to T3 (more active form).
- Protein Binding: >99% of thyroid hormone is protein-bound (inactive); only free hormone is active.
- Metabolic Effects: Affects metabolism in all tissues; increases beta-adrenergic receptor expression and sensitivity.
- Iodine Effects: Wolff-Chaikoff effect (excess iodide inhibits hormone release), Jod-Basedow effect (iodide load induces hyperthyroidism).
Clinical Manifestations
- Classic Presentation:
- Fever
- tachycardia
- altered mental status
- Symptoms and Signs by System:
| Organ System | Symptoms | Signs |
|---|---|---|
| CNS | Anxiety confusion delirium | Hyperreflexia seizures coma |
| psychosis, lethargy | ||
| Cardiovascular | Palpitations chest pain dyspnoea | Sinus tachycardia atrial fibrillation |
| on exertion | widened pulse pressure heart failure | |
| Gastrointestinal | Abdominal pain nausea vomiting | Diarrhea jaundice |
| diarrhea | ||
| Thyroid Gland | Neck fullness | Tenderness diffuse enlargement bruit |
Diagnosis
- Clinical Evaluation: Based on symptoms; serum testing is unreliable in acute states.
- Burch-Wartofsky Scale: Commonly used system for rapid recognition and diagnosis.
- Laboratory Findings: Low TSH, elevated T3/T4, hyperkalemia, hyponatremia, anemia, thrombocytopenia, low serum creatinine, hypercalcemia.
Management Basics
- Initial Stabilization:
- Evaluate airway and breathing
- establish IV access
- cardiac monitoring
- active cooling measures
- empiric fluid administration
- empiric broad-spectrum antibiotics
- Specific Treatments:
- Beta Blockers: Propranolol (0.5-1 mg IV, repeat q5-10 min, titrate to HR < 100), Esmolol as an alternative.
- Thionamides: Propylthiouracil (PTU) (600-1000 mg PO load, 300 mg PO q6h), Methimazole (20-30 mg q6h).
- Corticosteroids: Hydrocortisone (100 mg IV q8h), Dexamethasone (2-4 mg IV q6h).
- Inorganic Iodine: Potassium iodide (SSKI) (5 gtt q6h), Lugol’s solution (4-8 gtt q6h), Lithium (300 mg q6-8h).
- Additional Interventions: Cholestyramine (4 g PO q6h), L-Carnitine (1 g PO q12h).
Disposition
- Admit to ICU: Requires highly monitored care.
Take Home Points
- Clinical Diagnosis: Suspect in patients with fever, altered mental status.
- Rapid Diagnosis: Use Burch-Wartofsky scale for quick initiation of treatment.
- Broad Spectrum Antibiotics: Consider due to frequent concomitant infections.
- Directed Management: Beta blockade followed by corticosteroids, thionamides, and inorganic iodine.