Signs and Symptoms of Thyroid Storm
Thyroid storm presents with multisystem decompensation characterized by cardiovascular manifestations (tachycardia, arrhythmias, congestive heart failure, hypotension), thermoregulatory dysfunction (hyperpyrexia), neuropsychiatric symptoms (agitation, delirium, psychosis, stupor, coma), and gastrointestinal disturbances (nausea, vomiting, diarrhea, hepatic failure). 1
Cardiovascular Manifestations
The cardiovascular system is prominently affected in thyroid storm:
- Tachycardia - often severe and out of proportion to fever
- Cardiac arrhythmias - including atrial fibrillation
- Congestive heart failure - from high-output cardiac state
- Hypotension - indicating cardiovascular collapse and poor prognosis
These cardiac manifestations can progress to multiorgan failure requiring mechanical support, including ECMO in severe cases 2, 3.
Thermoregulatory Dysfunction
Hyperpyrexia (high fever) is a hallmark feature, often exceeding 40°C (104°F). This distinguishes thyroid storm from uncomplicated thyrotoxicosis and reflects the hypermetabolic crisis 1.
Neuropsychiatric Symptoms
Central nervous system dysfunction manifests along a spectrum:
- Agitation and restlessness - early signs
- Delirium and psychosis - intermediate severity
- Stupor and coma - indicating severe decompensation and poor prognosis
The presence of altered consciousness should raise immediate concern for life-threatening thyroid storm 1, 4.
Gastrointestinal and Hepatic Manifestations
- Nausea and vomiting
- Diarrhea
- Acute liver failure - can develop rapidly and contraindicate standard antithyroid drug therapy
Critical pitfall: Thyroid storm may present predominantly with gastrointestinal symptoms and minimal classical features, leading to diagnostic anchoring on other conditions. 5 reported a fatal case where persistent gastrointestinal symptoms were initially attributed to superior mesenteric artery syndrome, delaying recognition of thyroid storm. Early thyroid function testing should be considered in patients with unexplained persistent gastrointestinal symptoms accompanied by systemic deterioration 5.
Respiratory Manifestations
Acute respiratory failure requiring mechanical ventilation can occur, particularly when multiorgan failure develops 2.
Clinical Context and Precipitants
Maintain high suspicion for thyroid storm in patients with known or suspected thyrotoxicosis who develop systemic decompensation. Common precipitants include:
- Abrupt cessation of antithyroid drugs
- Surgery (thyroid or nonthyroidal) in inadequately treated patients
- Acute illnesses unrelated to thyroid disease
- Iodine exposure from contrast agents 1, 6
- COVID-19 infection 7
- Rarely, radioactive iodine therapy 1
Diagnostic Considerations
Diagnosis is primarily clinical, supported by validated scoring systems (Burch-Wartofsky Point Scale, Japanese Thyroid Association criteria) that also predict outcomes 4, 7, 3. The key is recognizing thyrotoxicosis with evidence of systemic decompensation across multiple organ systems 1.
Important caveat: Thyroid storm can occur in patients without prior thyroid disease history, particularly postpartum women. Consider thyroid storm in patients presenting with unexplained tachycardia, fever, diarrhea, sweating, and altered consciousness, even without known thyroid disease 4. Diagnostic delay is associated with increased need for intensive care and organ support, with longer delays occurring in older patients, those with initial onset (versus recurrence), and those admitted to non-emergency departments 8.