What are the symptoms and treatment of thyroid storm in a patient with a history of untreated or undertreated hyperthyroidism?

Symptoms of Thyroid Storm

Thyroid storm is a life-threatening medical emergency characterized by severe acute exacerbation of all hyperthyroidism symptoms, particularly marked fever, extreme tachycardia, and altered mental status ranging from agitation to coma. 1, 2

Cardinal Clinical Features

Cardiovascular manifestations:

• Severe tachycardia (heart rate typically >140 bpm) 1, 2
• Hypertension or hypotension depending on severity 1
• Atrial fibrillation and other arrhythmias 1, 3
• Congestive heart failure and cardiogenic shock in severe cases 2, 3

Thermoregulatory dysfunction:

• Marked hyperpyrexia (fever often >104°F/40°C) 2, 3
• Profuse sweating and heat intolerance 1, 4

Neuropsychiatric symptoms:

• Altered mental status is a defining feature 2, 3
• Agitation, confusion, delirium 4, 3
• Seizures or coma in severe cases 3
• Extreme nervousness and tremors 1

Gastrointestinal manifestations:

• Nausea, vomiting, abdominal pain 3
• Diarrhea 2
• Fulminant hepatic failure (rare but life-threatening complication) 3

Exaggerated Hyperthyroid Symptoms

All baseline hyperthyroidism symptoms become dramatically worse 1, 2:

• Insomnia progressing to severe sleep deprivation 1
• Tremors becoming uncontrollable 1
• Weight loss despite increased appetite 2
• Muscle weakness 2

Physical Examination Findings

Thyroid gland:

• Goiter (enlarged thyroid) 1
• Thyroid bruit may be present 2

Ophthalmologic signs (if Graves' disease):

• Eyelid lag or retraction 1
• Exophthalmos 1

Dermatologic findings:

• Warm, moist skin from excessive sweating 4
• Pretibial myxedema (in Graves' disease) 1

Critical Pitfalls in Recognition

Do not wait for laboratory confirmation to initiate treatment—thyroid storm is a clinical diagnosis and mortality rises significantly with treatment delays. 2 The diagnosis must be made based on clinical presentation in patients with known or suspected hyperthyroidism who develop the characteristic triad of hyperpyrexia, extreme tachycardia, and altered mental status 2.

Common precipitating factors to identify:

• Infection (most common) 2, 5
• Surgery or trauma (including direct thyroid injury) 5, 6
• Acute medical illness 1
• Medication non-adherence in known hyperthyroid patients 2
• Pregnancy/labor/delivery 1, 4
• Rapid sequence intubation or anesthesia 6
• Viral infections including Epstein-Barr virus 3

In pregnant women specifically:

• Thyroid storm affects less than 1% of pregnant women with hyperthyroidism but carries extremely high maternal and fetal mortality 1, 2
• Suspect in any pregnant patient with resting heart rate >100 bpm and weight gain inconsistent with gestational age 4

Multiorgan Dysfunction

Thyroid storm represents multiorgan system decompensation 2, 3:

• Cardiovascular collapse requiring vasopressor support 2
• Respiratory failure requiring mechanical ventilation 4
• Hepatic failure with elevated transaminases 3
• Renal insufficiency 2
• Coagulopathy 7

The mortality rate reaches 75% if treatment is delayed, and 30% even with appropriate treatment. 2, 6, 3 Recognition requires high clinical suspicion in any patient with known or undiagnosed hyperthyroidism who develops acute decompensation with the characteristic symptom constellation.