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side by side comparison

Thyroid Storm vs Myxedema Coma: The Two Thyroid Emergencies

A delirious patient with a temp of 105°F and a heart rate of 160 needs the exact opposite intervention from an obtunded patient at 94°F with a heart rate of 42. These two thyroid emergencies mirror each other — every vital sign, every symptom, every drug is reversed. Pick the wrong one on the NCLEX and you accelerate the crisis.

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Comparison

Side-by-side2 compared
Focus
Dimension
Thyroid Storm
Myxedema Coma
Pathophysiology & risk
  • Extreme hyperthyroidism
  • Trigger: infection
  • Trigger: surgery or iodine load
  • Trigger: stopping antithyroid drugs
  • Extreme hypothyroidism
  • Trigger: infection
  • Trigger: cold exposure, sedatives
  • Trigger: stopping levothyroxine
Signs & symptoms
  • ★Hyperthermia > 104°F (40°C)
  • Severe tachycardia 140–180
  • AFib common
  • Agitation, delirium, seizures
  • ★Hypothermia < 95°F (35°C)
  • Bradycardia 40–60
  • Heart block risk
  • Lethargy, stupor, coma
  • Hypoventilation
Diagnostics & labs
  • ↑↑ free T3/T4, ↓ TSH
  • Hyperglycemia, ↑ LFTs
  • ↓↓ free T3/T4, ↑ TSH
  • Hyponatremia + hypoglycemia
Nursing priorities
  • ★Aggressive cooling (blankets, ice packs)
  • Avoid aspirin (frees bound T4)
  • Liberal IV fluids (fever losses)
  • Continuous cardiac monitoring
  • ★Passive rewarming; no active warming
  • Support airway/ventilation
  • Cautious IV fluids (overload risk)
  • Continuous cardiac monitoring
Treatment & meds
  • Propranolol (HR control)
  • PTU or methimazole
  • Iodine ≥ 1 hr after PTU
  • IV hydrocortisone
  • IV levothyroxine loading dose
  • IV hydrocortisone
  • IV dextrose for hypoglycemia
Patient teaching
  • Take antithyroid meds
  • Never stop meds abruptly
  • Report fever or racing heart
  • Lifelong levothyroxine
  • Never stop meds abruptly
  • Avoid sedatives/opioids
  • Dress warmly, avoid cold
Red flags — escalate
  • Temp > 106°F (41°C)
  • AFib with RVR
  • Seizures
  • Respiratory failure (CO₂ narcosis)
  • Profound bradycardia / heart block
Complications
  • High-output heart failure
  • Tachyarrhythmias
  • Death if untreated
  • Respiratory failure
  • Refractory hypotension
  • Death if untreated
Pathophysiology & risk

Thyroid Storm

  • Extreme hyperthyroidism
  • Trigger: infection
  • Trigger: surgery or iodine load
  • Trigger: stopping antithyroid drugs

Myxedema Coma

  • Extreme hypothyroidism
  • Trigger: infection
  • Trigger: cold exposure, sedatives
  • Trigger: stopping levothyroxine
Signs & symptoms

Thyroid Storm

  • ★Hyperthermia > 104°F (40°C)
  • Severe tachycardia 140–180
  • AFib common
  • Agitation, delirium, seizures

Myxedema Coma

  • ★Hypothermia < 95°F (35°C)
  • Bradycardia 40–60
  • Heart block risk
  • Lethargy, stupor, coma
  • Hypoventilation
Diagnostics & labs

Thyroid Storm

  • ↑↑ free T3/T4, ↓ TSH
  • Hyperglycemia, ↑ LFTs

Myxedema Coma

  • ↓↓ free T3/T4, ↑ TSH
  • Hyponatremia + hypoglycemia
Nursing priorities

Thyroid Storm

  • ★Aggressive cooling (blankets, ice packs)
  • Avoid aspirin (frees bound T4)
  • Liberal IV fluids (fever losses)
  • Continuous cardiac monitoring

Myxedema Coma

  • ★Passive rewarming; no active warming
  • Support airway/ventilation
  • Cautious IV fluids (overload risk)
  • Continuous cardiac monitoring
Treatment & meds

Thyroid Storm

  • Propranolol (HR control)
  • PTU or methimazole
  • Iodine ≥ 1 hr after PTU
  • IV hydrocortisone

Myxedema Coma

  • IV levothyroxine loading dose
  • IV hydrocortisone
  • IV dextrose for hypoglycemia
Patient teaching

Thyroid Storm

  • Take antithyroid meds
  • Never stop meds abruptly
  • Report fever or racing heart

Myxedema Coma

  • Lifelong levothyroxine
  • Never stop meds abruptly
  • Avoid sedatives/opioids
  • Dress warmly, avoid cold
Red flags — escalate

Thyroid Storm

  • Temp > 106°F (41°C)
  • AFib with RVR
  • Seizures

Myxedema Coma

  • Respiratory failure (CO₂ narcosis)
  • Profound bradycardia / heart block
Complications

Thyroid Storm

  • High-output heart failure
  • Tachyarrhythmias
  • Death if untreated

Myxedema Coma

  • Respiratory failure
  • Refractory hypotension
  • Death if untreated

★ marks the fact that sets a column apart.

Clinical Pearl

Storm = hot, fast, wild — cool down and beta-block. Myxedema = cold, slow, silent — warm up and give IV T4.

Component Topics

HypothyroidismThyroid Storm

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