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side by side comparison

Hypothyroidism vs Hyperthyroidism: Everything Slow vs Everything Fast

The NCLEX hands you a set of vitals and a symptom cluster — bradycardia with constipation or tachycardia with diarrhea — and expects you to pick the correct thyroid disorder in seconds. Reversing even one finding (like temperature intolerance) leads you to the wrong diagnosis and the wrong intervention.

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Comparison

Side-by-side2 compared
Focus
Dimension
Hypothyroidism
Hyperthyroidism
Pathophysiology & risk
  • ↓ Thyroid hormone, slowed metabolism
  • Hashimoto's, post-RAI/thyroidectomy
  • ↑ Thyroid hormone, fast metabolism
  • Graves' autoimmune (TSI antibodies)
Signs & symptoms
  • Bradycardia, cold intolerance
  • Weight gain, constipation
  • Lethargy, depression
  • Dry coarse skin, periorbital edema
  • ★Exophthalmos (Graves')
  • Tachycardia/AFib, heat intolerance
  • Weight loss, diarrhea
  • Anxiety, tremor, insomnia
Diagnostics & labs
  • ★↑ TSH (primary)
  • ↓ T3, ↓ T4
  • ★↓ TSH (suppressed)
  • ↑ T3, ↑ T4
Nursing priorities
  • Provide warmth
  • Monitor for bradycardia, hypotension
  • Prevent constipation
  • Cool, low-stimulation environment
  • Cardiac monitoring (AFib)
  • Eye protection (lubricate eyes)
Treatment & meds
  • Levothyroxine daily, empty stomach
  • Lifelong replacement
  • Methimazole or PTU
  • Beta-blocker for symptoms
  • Radioactive iodine or thyroidectomy
Patient teaching
  • Same time daily, 30–60 min before food
  • Lifelong therapy, never stop
  • Report palpitations (dose too high)
  • ★Report sore throat or fever
  • RAI radiation precautions
  • Wear sunglasses, protect eyes
Red flags — escalate
  • Myxedema coma: hypothermia, ↓ LOC
  • Passive rewarming (blankets)
  • IV levothyroxine
  • Thyroid storm: high fever, tachycardia
  • Cooling, beta-blocker, PTU, iodine
Complications
  • Myxedema coma
  • Pericardial effusion
  • Atrial fibrillation
  • High-output heart failure
  • Osteoporosis
Pathophysiology & risk

Hypothyroidism

  • ↓ Thyroid hormone, slowed metabolism
  • Hashimoto's, post-RAI/thyroidectomy

Hyperthyroidism

  • ↑ Thyroid hormone, fast metabolism
  • Graves' autoimmune (TSI antibodies)
Signs & symptoms

Hypothyroidism

  • Bradycardia, cold intolerance
  • Weight gain, constipation
  • Lethargy, depression
  • Dry coarse skin, periorbital edema

Hyperthyroidism

  • ★Exophthalmos (Graves')
  • Tachycardia/AFib, heat intolerance
  • Weight loss, diarrhea
  • Anxiety, tremor, insomnia
Diagnostics & labs

Hypothyroidism

  • ★↑ TSH (primary)
  • ↓ T3, ↓ T4

Hyperthyroidism

  • ★↓ TSH (suppressed)
  • ↑ T3, ↑ T4
Nursing priorities

Hypothyroidism

  • Provide warmth
  • Monitor for bradycardia, hypotension
  • Prevent constipation

Hyperthyroidism

  • Cool, low-stimulation environment
  • Cardiac monitoring (AFib)
  • Eye protection (lubricate eyes)
Treatment & meds

Hypothyroidism

  • Levothyroxine daily, empty stomach
  • Lifelong replacement

Hyperthyroidism

  • Methimazole or PTU
  • Beta-blocker for symptoms
  • Radioactive iodine or thyroidectomy
Patient teaching

Hypothyroidism

  • Same time daily, 30–60 min before food
  • Lifelong therapy, never stop
  • Report palpitations (dose too high)

Hyperthyroidism

  • ★Report sore throat or fever
  • RAI radiation precautions
  • Wear sunglasses, protect eyes
Red flags — escalate

Hypothyroidism

  • Myxedema coma: hypothermia, ↓ LOC
  • Passive rewarming (blankets)
  • IV levothyroxine

Hyperthyroidism

  • Thyroid storm: high fever, tachycardia
  • Cooling, beta-blocker, PTU, iodine
Complications

Hypothyroidism

  • Myxedema coma
  • Pericardial effusion

Hyperthyroidism

  • Atrial fibrillation
  • High-output heart failure
  • Osteoporosis

★ marks the fact that sets a column apart.

Clinical Pearl

Hypo = cold, slow, heavy, constipated. Hyper = hot, fast, thin, diarrhea — opposites across every system.

Component Topics

Hyperthyroidism & Graves' DiseaseHypothyroidism

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