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
Dimension
Thyroid Storm
Myxedema Coma
Pathophysiology & risk
  • Extreme hyperthyroidism (↑↑ T3/T4, ↓ TSH)
  • Trigger: infection, surgery, abrupt drug stop, iodine
  • Extreme hypothyroidism (↓↓ T3/T4, ↑ TSH)
  • Trigger: infection, cold, sedatives, noncompliance
Signs & symptoms
  • ★Hyperthermia > 104°F (40°C)
  • Severe tachycardia 140–180
  • AFib
  • Agitation then delirium then seizures then coma
  • ★Hypothermia < 95°F (35°C)
  • Bradycardia 40–60
  • heart block risk
  • Lethargy then obtundation then coma
  • hypoventilation
Diagnostics & labs
  • ↑↑ free T3/T4, ↓ TSH
  • Hyperglycemia, ↑ LFTs
  • ↓↓ free T3/T4, ↑ TSH
  • Hyponatremia + hypoglycemia
Nursing priorities
  • ★Aggressive cooling (blankets, ice packs)
  • Avoid ASA (displaces T4)
  • IV fluids
  • telemetry
  • ★Passive rewarming only — active then collapse
  • Support airway/ventilation
  • cautious IV fluids
Treatment & meds
  • Propranolol (rate; blocks T4→T3)
  • PTU/methimazole
  • iodine 1 hr after
  • hydrocortisone
  • IV levothyroxine loading dose
  • IV hydrocortisone
  • cautious glucose correction
Patient teaching
  • Take antithyroid meds
  • never stop abruptly
  • Know storm triggers (infection, stress)
  • Lifelong levothyroxine
  • never skip
  • Avoid sedatives/opioids
  • dress warm
Red flags — escalate
  • Temp > 106°F
  • AFib with RVR
  • seizures
  • Respiratory failure (CO₂ narcosis)
  • Profound bradycardia / heart block
Complications
  • High-output heart failure
  • arrhythmia
  • death
  • Respiratory failure
  • refractory hypotension
  • death
Pathophysiology & risk

Thyroid Storm

  • Extreme hyperthyroidism (↑↑ T3/T4, ↓ TSH)
  • Trigger: infection, surgery, abrupt drug stop, iodine

Myxedema Coma

  • Extreme hypothyroidism (↓↓ T3/T4, ↑ TSH)
  • Trigger: infection, cold, sedatives, noncompliance
Signs & symptoms

Thyroid Storm

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

Myxedema Coma

  • ★Hypothermia < 95°F (35°C)
  • Bradycardia 40–60
  • heart block risk
  • Lethargy then obtundation then 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 ASA (displaces T4)
  • IV fluids
  • telemetry

Myxedema Coma

  • ★Passive rewarming only — active then collapse
  • Support airway/ventilation
  • cautious IV fluids
Treatment & meds

Thyroid Storm

  • Propranolol (rate; blocks T4→T3)
  • PTU/methimazole
  • iodine 1 hr after
  • hydrocortisone

Myxedema Coma

  • IV levothyroxine loading dose
  • IV hydrocortisone
  • cautious glucose correction
Patient teaching

Thyroid Storm

  • Take antithyroid meds
  • never stop abruptly
  • Know storm triggers (infection, stress)

Myxedema Coma

  • Lifelong levothyroxine
  • never skip
  • Avoid sedatives/opioids
  • dress warm
Red flags — escalate

Thyroid Storm

  • Temp > 106°F
  • AFib with RVR
  • seizures

Myxedema Coma

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

Thyroid Storm

  • High-output heart failure
  • arrhythmia
  • death

Myxedema Coma

  • Respiratory failure
  • refractory hypotension
  • death

★ 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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